Aerovox ACD23 2 Decade Capacitance Box - .01Mf to 1Mf in 100 Steps bap8guy 2023-02-08 | This is a companion box to the ACD13, that continues into 2 more decades of selectable capacitance. This unit provides switch selectable capacitances, covering .01Mf to 1Mf in 100 steps, of .01Mf each. It was likely made in the later 1960's to the mid 1970's. It is in good condition. This is the introduction and test video for the unit.
Aerovox ACD13 A 2 Decade Capacitance Substitution device bap8guy 2023-02-08 | This Aerovox ACD13 is a handy 2 decade capacitance substitution device that will provide switch selectable capacitance of any value from .0001Mf to .01Mf in 100, .0001Mf steps. Further, it is usable up to 600v DC, or 220v AC. It was made (probably) in the late 1960's to the mid 1970's. It contains silver mica capacitors made by Aerovox Corporation.
ESI DV411 intro and testing (unit 5) bap8guy 2023-02-01 | This is a precision made Kelvin Varley voltage divider made by Electro Scientific Industries, probably in the 1960's. It has 100k ohms of impedance (resistance), 4 rotating dials (3 are stepped and 1 is a continuously variable pot), and can divide voltages up to about 750v. In my test video, I provide a 9.9999v reference voltage into the unit from a very stable Fluke 343A and feed it into the divider input. I have a very high input impedance voltmeter attached to the output (an HP34401A set to 10Gig ohm of input impedance). After allowing several hours of stabilization on both the Fluke and the HP in a temperature controlled environment, I proceed to measure and step the divider down each of it's dial steps, until I hit zero. The results are recorded and entered into a spreadsheet and the error of output reading to expected divider setting is made. The unit's maximum error in 4 decimal places was .0033 % (3.3 thousandths of a percent)!!!It was a relatively expensive device when new. To give an understanding of this, I submit that Tegram still sells a similar device for about $5,000. If anyone has information on the original price, I would appreciate that you share the information.Devices like this are useful for calibration, or calibration checks of voltmeters (I use a HP34401A in the video), or can provide a reference voltage (for extremely high input impedance inputs) that could be used in power supplies etc. It can also translate voltages, dividing them down to some usable level (for example, I have a high input impedance 1V meter, but want to measure 10v or 100v).This unit was purchased, tested, taken apart, internally and externally cleaned, painted, rebuilt and tested on video (for you to view). It is an extraordinary device, even after all these years!
Gen Rad 1419M - For Sale on Ebay bap8guy 2023-01-12 | This unit is in excellent condition. It has been cleaned, tested and brought up to spec. The test results are recorded on the video and summarized at the end.It is a solid 3 decade capacitance substitution unit, capable of covering from .001mf to 1mf in 1000 switch select-able steps. The voltage rating is up to 500v dc.
keithley 414S bap8guy 2022-07-24 | This Keithley 414S Picoammeter was built in the late 60's/early 70's and was in production until the early 80's. It can measure 10mA FS, to .1nA FS in 17 ranges. The .1nA range is also 100 picoamp range and the meter is divided into 100 little steps, each a picoamp (a millionth of a millionth of an Amp!).When it arrived, I saw the cord was cut off of the unit, but could find nothing else that was obviously defective. I replaced the cord, plugged it in and turned it on, only to blow my GFI. I reset the GFI and tried again, with the same response. There was only the primary side of the transformer and a fuse/power switch on the electrical inlet. I checked for shorts, even high resistance ones, but found nothing. I looked at the schematic and saw that the transformer had a shield wire on the primary and figured it was possible that enough current collected there to set off the GFI. I know, with some experience, that some of the older equipment has been known to trigger GFIs. I connected the unit to my isolation transformer and turned it on, and everything worked fine. No blown fuse, no problems noticeable anywhere. So, I started looking for a small isolation transformer, found one and ordered it.When the isolation transformer arrived, I decided how to best hook it up into the circuit. I kept the fuse and power switch on the primary input side of the isolation transformer and hooked the secondary to the existing transformer input. That all worked fine! Now to test it’s operation and ranges.Pulling out my Keithley 225 current source and connecting it to the input, I began to check the zero and span on each of the ranges. I found that the 414S switches were a bit erratic, so I shut everything down and gave them a good cleaning. I went back to checking the ranges. I found about half were out of spec (+/-) 2 to 4%, placing the span on the range either low, or high, by 2 to 4 least significant digits on the meter. Altogether, there were 7 range resistors that were out of tolerance. I determined which of the resistors I had on hand, and then replaced the range resistors in the unit with them, each time finding the results to be satisfactory. I then ordered the remainder of the resistors, except for the lowest two ranges, which required a 1% 10Gig ohm resistor (these cost about $100 each). It was at this point I realized that I had no satisfactory means to measure the 10G ohm resistor on my bench. Something I needed to remedy! (See “Extreme Resistance Instrument”.) When the resistors showed up to the house, I installed them in place of the defective resistors (on the appropriate ranges) and again saw good, satisfactory results. Finally I got down the .1na range ( 100 picoamps). I did not want to spend over $100 on a new 10G, 1% resistor. I noted that the reading was low about 3% of the meter span. I calculated that 3% of 10G would be about 300M ohm. But, am I 300M ohm low, or high in resistance on the 10G ohm? I looked at the schematic and saw that there was a “op amp” circuit that fed off the voltage drop across the input resistors R123 and R124. In the 10G (.1na) it was only R124. R123, R124 and R125 all measured good. In order to “push” a tiny bit more current through R124 and get the 3% greater reading, I would need to increase the resistance of R122 (10G) by 300M ohm. I found a suitable 300M ohm resistor on Ebay for about $8 shipped and I ordered it.Getting to R122 is difficult, unless you remove the suppression range switch assembly. That assembly is held in by a wire, an aluminum wire rod, and a hex nut under the knob. With those removed, the suppression assembly slid right out and I had (mostly) unobstructed access to R122. I cut one end of R122, and pulled it outward somewhat. I decided to first put a shrink tubing around R122, to act as an additional insulator to the 300M resistor I was installing in series with it. Then I made little wire extensions to the 300M ohm resistor leads, which I coated with shrink tubing as well, leaving both ends protruding from out of one end of the resistor. Then I slid a large tube shrink tubing around R122 and the 300M resistor, leaving the cut end of R122 and both ends of the 300M resistor protruding. I connected one lead of the 300M resistor to the open end of R122, and pulled the connection to the side, getting it away from the other 300M lead. Then I connected the remaining 300M lead to the switch wafer-connector that the R122 used to connect to. I heated the shrink tubing and it was done. Finally, I reinstalled the suppression switch unit and buttoned up the case.I plugged the unit in, fed a .1nA signal into it, and dialed the range switch down to the last two range settings of .3nA and .1nA. The meter dial responded satisfactorily now! At this most sensitive level, I did notice that the unit is very sensitive to any movement of my body nearby, as I took the readings.
Eco Amel 731- Integrator/Coulomb Counter bap8guy 2022-06-23 | This early '80s instrument performs integration of current streams to obtain the total Coulombs of charge moved during a measurement period. This is most often used for determining battery charge states, or in electro-chemistry (like plating and others). However, I show in this video how it could be used to determine the capacitance of relatively large capacitors (which is difficult to do with most LCR meters). We give a quick tour of the unit, inspect the interior, determine the inputs and operational controls. We then integrate current from a standard to see if the resultant coulomb value is as expected, then we use it to measure capacitance of capacitors (some very large ie- 20,000Mfd).
UTC DI 2 Decade Inductor - .1H per step to 1H bap8guy 2022-06-18 | A decade inductor made by United Transformer Corporation, that covers .1H to 1H in .1H steps. It can handle up to 150ma max of AC current and 500v max. In the video I test the steps using a DER EE 5000 LCR meter and display the results.
Kemo VBF 8, A dual Elliptical 90db/octave, .01Hz to 99.9Khz Range bap8guy 2022-06-16 | This Kemo VBF-8 series dual filter unit is still being produced in it's 5th generation unit called benchmaster. You can read about the use of this model unit in many prestigious papers published at major institutions the last few decades. The VBF-8 is a dual filter unit, each configurable as either a low pass or high pass filter with a 3 digit dial in setpoint that covers .01Hz to 99.9Khz in range, using a 5 position range switch. It has an input impedance of 1Meg ohm, 2% cuttoff accuracy, low noise, two position gain switch, an output monitor for each unit, and a 50 ohm output. An additional function switch allows for the filters to be placed in series (for bandpass) and parallel (for notch filtration).These are very high end units with remarkable performance.In the video I introduce the VBF-8, walk you around the unit and demonstrate it's use in a couple of scenarios.
Rockland 5100 - .001Hz to 2Mhz in .001Hz Steps bap8guy 2022-06-16 | The Rockland 5100 is a early 70's DDS generator capable of producing crystal controlled frequencies from .001Hz to 2Mhz in .001Hz steps! It has a line of 10 dials to select the frequency desired, has a variable output, switch selectable attenuation of 1/2/4/8/10/20/40dB, a 1vPP fixed output, outputs front and rear and a programming port for remote control and monitoring. It is a valuable tool for investigation of frequencies and filters within it's range.In this video I introduce the unit, walk you around it, demonstrate it's use and precision. Towards the videos end I demonstrate it's use in setting up and testing the effectiveness of a .145Hz infrasonic filter, where a 1/10th hz change in frequency makes a dramatic change in output voltage.
BK1801 20Hz to 40Mhz Frequency Counter bap8guy 2022-06-07 | This is a nice example of a working BK1801. It is in nice condition both physically and operationally. The 1801 is expected to cover 20Hz to 40Mhz, but as this video demonstrates, it is capable of comfortably performing up to 60Mhz, with 50Mhz being a nice working maximum.This unit will be accompanied by a CD service manual.
Freed 1162 Decade Inductor bap8guy 2022-06-05 | Looking very similar to the 1160 Decade Inductor, it is different because of the ranges involved. The 1162 covers from .0001Hy to .11Hy in .0001Hy steps, so it provides two lower decades of inductance not found on the 1160.The 1162 is being tested at 100Hz, using a DER5000 as the standard. The test results are on the video.
Freed 1160 bap8guy 2022-06-02 | FREED 1160DECADE INDUCTOR.01Hy to 11.11Hy in .01Hy Steps3 DecadesNice looking unit, Mahogany case, functioning beautifully! Better than 1.5% accuracy (measured at 100Hz) on all stepsMost steps are better than 1%. Probably from the late 1950's / early 1960's.
WAVETEK 114 - Function/Sweep/VCG Generator bap8guy 2022-05-31 | This Wavetek multi function unit will produce sine, triangle & square waves from .0015Hz to 1Mhz in 9 ranges, but will do so at a continuous user selected frequency, or sweep up to it, sweep around the selected frequency, or provide a burst at the selected frequency. The sweeps can be continuous, manually triggered, or externally triggered. The sweep frequency can be internally generated, or externally generated and can cover as much as a 20/1 sweep range. The output voltage can be as high as +/-10v pp into 50ohms, or +/-30v into 600 ohms at the output. The VCG input allows for external sweeping, or for frequency modulation of the chosen center frequency. Apply a positive voltage to input and the selected frequency is increased, apply a negative voltage to the input and selected frequency is decreased (thus the possibility for FM modulation). This unit can simultaneously produce up to 9 independent outputs from the front and back connector terminals.
Wavetek 103 Function Generator bap8guy 2022-05-24 | This video demonstrates a Wavetek 103 Function Generator. The function generator is a multiuse tool for the bench and shines in the design and testing of analog and digital circuitry. This unit is from the 60's / 70's. The Wavetek 103 is an all transistor device that provides triangle, sine, and square wave outputs, with adjustable amplitude up to 30v p-p. It also has two more specialized fast risetime square wave outputs (one as fast as 5nS risetime).
HP465A Wideband Amplifier bap8guy 2022-05-14 | The HP465A is a handy bench unit for the preset amplification of low voltage signals in the 5Hz to 1Mhz range. You can select either a x10, or a x100 gain setting for the amplifier, at the flip of a switch. This means you can amplify signals for your bench equipment that would otherwise not work properly. For instance, you want to read a 1mv signal on your frequency meter, but that signal is too low to drive the meter. Solution: amplify the signal x100 and now you have a .1v signal to operate your equipment. I demonstrate several such instances in the video.It is an attractive, nicely packaged amplifier for your bench.
BK1570A - bap8guy 2022-05-12 | This is a BK1570A 4 Channel 80Mhz scope. Two channels (1 & 2) have adjustable vertical volts/div ranges, while the remaining two channels are fixed voltage (.1v/div).This unit was damaged in delivery, but was brought back to the shape displayed. It will be sold for parts, or repair.
HP461A Wideband Preamplifier bap8guy 2022-05-03 | An oldie, but goodie! The HP461A covers 1Khz to 150Mhz +/- 1 dB. It provides for switch selectable 20dB (10x) or 40dB (100x) gain. It is a very helpful tool for amplifying signals too small for direct analysis on frequency counters and oscilloscopes and can be used for amplifying small signals for measurements, listening, or RF boosting! The video demonstrates this beauty in several cases.
LM399 Based Temperature Controlled 10v Voltage Ref PART 2 bap8guy 2022-04-23 | Using a purchased LM399 10v ref board from Germany, I have added temperature control and added RS232 communication from my HP34401A DVM to my computer to provide long term analysis of it's performance. Despite problems with hysteresis met in voltage adjustment, I am getting about 10.00000 +/- .000005 microvolts (maybe a bit less normally). By carefully (and patiently) adjusting the temperature control, .1 degree C at a time, I have been able to center the voltage so that it seldom travels out of it's 10.00000v output.I have utilized a fairly large heat sink to dissipate/ distribute the heat across components of the board. I have also reduced the wattage of my original heat plate to slow down the reaction time needed by the temperature controller. Additionally, I inserted a diode in one of the heater plates leads to remove an additional half of the heater voltage, slowing down the heating process even further. The results have improved with each step.
HP34401A RS232 Communications to PC bap8guy 2022-04-23 | Working on projects that involved a lot of collection and graphing of voltage data prompted me to try to establish communication from HP34401A DVM to my Windows 10 computer.In this film I introduce you to the means by which I was able to make this happen, in a most pleasant way!
Helipot Project bap8guy 2022-03-12 | I had an old Beckman Model A Helipot in my salvage parts pile (probably from the '70's) that I thought I could get some use out of. So, this was the start of this project.This 1,000 ohm Helipot has large power handling capacity (5W), excellent linearity (.05%), and it came with a really unique 10 turn dial system! This combination makes for some desirable uses! It is a variable resistor from about 0 to 1000 ohms and it can handle up to 5w. This means it can be a temporary replacement for very large number of resistors, with no fear. This also means that it can be used in a voltage divider circuit. Place 1 volt across it, and take your voltage off the tap and you will be able to adjust for a voltage from about 0 to 1v (with .001a flowing through the pot, generating .001w). Put 10v across it and do the same, and now you have 0 to 10v available (wattage is now .01w). Place another resistor in series with the unit and voltage source and you can extend the range, or "tune in the dial" calibration. See the video for a better explanation.
ESI DV411 Precision 5 Decade DC Voltage Divider - unit3 b bap8guy 2022-03-09 | Precision made 5 decade DC Voltage Divider, of the Kelvin Varley type. The first 3 decades are controlled via 10 position switches, the last two decades are controlled by a precision made wire potentiometer with finely graduated dial. These units were used in the 1950's and '60's and made through the 1970's, although they may look somewhat different. KVD dividers are still manufactured for use and can be quite expensive.The unit is an excellent piece of equipment to utilize with a stable precision voltage source, like 1v or 10v. It will then provide a user selectable division of the voltage that will remain precise so long as the unit measuring the output does not load it. I would recommend nothing less than 10 meg ohms, but would prefer a gig or more of load impedance. In the case of the video, I used an HP34401A set to 10 gig ohms of input impedance. The resulting output voltages can be used to calibrate, or test a volt meters over a wide range of voltages. In this video, I introduce the unit, connect it to a 9.9999v stable input voltage and test the output of every step of 5 decades against the input dials. I then build a spreadsheet of the results and go over the results on the video.
BiPolar Adjustable Power Supply prt 2 bap8guy 2022-02-14 | The board chosen for the regulator is not capable as is, so I have had to replace the positive regulator and add heat sinks to the regulator ICs. Then I had to buy and install a fan to keep the components cools. This added a substantial rework of the cabinet, but that pulled through. The unit has proven capable of providing about half of the touted current capability even after all this additional work. It is likely I will replace the regulator/power supply board with a new one I bought as a kit. The new board has several substantial features that make if superior to the old board.
ESI 230B Resistance Bridge bap8guy 2022-02-07 | I picked up one of these bridges a few months ago in hopes of getting it to work and study it. Back in my early hobby years of the early 1960's, a unit like this would have been the means by which resistor batch (or even single unit) values were determined. It is a unit that has the potential to determine resistances from micro-ohms to 12,000 megohms in value, to better than .01%. In the video, I introduce the unit, open it up, show the interior, discuss the cleaning of the components and then I test the unit. Using 3, .01% tolerance resistances, I measure them using the 230B and also my HP34401A and then I compare the readings. The 230B comes out a champ!
Adjustable Bi-Polar Power Supply, 0-24v 1A bap8guy 2022-02-03 | Utilizing a low cost regulator board from China, I decided to cobble together a usable bench supply for use with my op amps. For the regulator to function as a usable adjustable power supply requires finding a good cabinet, switching the small trim pots to actual front panel potentiometers, installing an on/off switch, several terminal binding posts, and the construction of a transformer driven filtered power supply! All of this was done and the unit functioned...for awhile. The regulator board claims to be good to 1A, however there is not sufficient cooling for the regulators on the board. As a result, the positive regulator failed during testing and required replacement. I also have de-rated the supply to .5A until additional cooling can be installed. The video is a review of what has been done.
Volt-Amp-Watt Meter or The VAW Project bap8guy 2022-02-03 | Many times I have found myself working with power sensitive components at, or near their maximum ratings! When you do this you must keep in mind the maximum rating, know the voltage and current and calculate the power being handled. This can be cumbersome, if not down right dangerous!I ran across an inexpensive digital device that reads Voltage, Current and calculates and reads Wattage, all to 5 digits. So, I bought one. By itself it is difficult to use. You must supply power, provide positive and negative voltage sense and pass the current through the current terminals. That is a lot of wiring and mess. So, you need to box all that up into a usable tool. That is the gist of this video. Making a useable tool from a low price gadget!
LM399 based, 5 decimal place adjustable Voltage Reference Project bap8guy 2022-02-03 | With my DV411 voltage divider now working (see previous video), I began to integrate the components of my planned 5 decimal place Voltage divider project. The whole project is based around a 5 decimal place 10v reference source purchased from Gurauv Singh of Germany. I have had this unit for about a year, just waiting for me to get around to it. The LM399 board needs a clean stable source of 15v power and what I have used is a low noise power supply I cobbled together in an earlier project, based upon an LT3042 regulator. The LM399 board is temperature sensitive, so i decided to try and control the environment of the board. I had purchased an "egg incubator" temperature controller and a heating element from Ebay some time ago, for a good price. So, I cobbled together an enclosure big enough for the board, heating element, heat sink, and two temperature sensors. "As a side note, if you use one of these temperature controllers, practice setting the temperatures before using it on the board. Any mistakes in programming can send the unit into soaring temperature."I used a fairly large heat sink to absorb and more evenly distribute the heat from the controller/heating plate and to provide more temperature stability. The top temperature sensor gives me more of an idea of what is happening at the hot plate, and the lower sensor what is seen at the board level. There is a time lag between what the temperature controller sensor "sees" and the amount of heat stored withing the heating plate. So, I "pulse" the heat, applying only a minimum amount and then waiting for the overall effect. I have both the on and off point set to the same temperature. So, when the temperature falls to the "on" point, the heating plate comes on and heats the heat sink and sensor. When the sensor "sees" the off temperature point, it stops heating the plate and waits until the temperature sensor falls back down to the "on" point again. I am seeing as much as 2+ degrees C change between the set-point and the maximum temperature at the controller temperature sensor. The temperature sensor at the board varies little.Taking the output of the LM399 board to the input of the DV411 divider, I could now divide the incoming voltage into desired decimal amounts over 5 decades. Testing of the unit was made with encouraging success!
ESI DV411 unit 4 - Rigged to Function bap8guy 2022-02-03 | I purchased this DV411 for a good price, but unfortunately the linear potentiometer that provides the adjustment for the 4th and 5th decades was severely damaged. It will take time to find a suitable replacement, so I decided to "Gerry rig" a replacement. This video captures my "rig" and the subsequent testing of the unit, once completed. The unit works extremely well!!!I will be using this unit as the divider for an upcoming 5 decimal place Voltage Reference project, soon to be published.
5 Decade Capacitor bap8guy 2021-06-22 | I decided to build a 5 Decade Capacitor, using .5% Polystyrene capacitors, that would cover a range of .0001mf to 1mf in 5 steps. I used a 6 position switch, so that the 1st position would be 0 and I could read my residual capacitance (about 6pf).This gives me the capability to quickly check the linearity of my capacitance measuring devices over a large range of capacitance. Also, because they are precision Polystyrene capacitors I have a wide range of low leakage capacitance for use in filter design, integrators, sample hold scenarios etc.It was an easy, fun and rewarding little project, that I thought I would share.
Variac Project bap8guy 2021-06-17 | I found I had an old Staco 2.25 amp autotransformer in my scrap box. It looked to good to go to waste and I have been wanting a Variac power box for some time. So, I decided to go ahead and build one up!The video goes through my choice of box, schematic design and then construction. It turned out really nice. Thought it might stir someone else into a new project!
T Attenuator for General Radio 1840A Power Meters bap8guy 2021-06-16 | I wanted a nice meter to read out power levels of amplifiers and I found these General Radio 1840A units. They can adapt to a very wide range of load impedance, which is very nice, but they suffer in that they can only read 20W maximum. Since a lot of amplifiers I work on range up to 200W, this wouldn't seem to be a good solution. I read in the manual that you can build a "T" Attenuator that can shunt precisely 90% of the power around the GR1840A, giving it a 200W range. I decided to build a pair of these units to give each of my 1840A's 200W capability, but could I do it?In the video I explain how I went about ordering parts and analyzing the imperfections these parts had to the desired design. In the end I have a very nice 200W setup, verified using 2 different methods.Unlike many of my videos, this is not to sell something on Ebay. but to document a project I have recently undertaken.
General Radio 1454A bap8guy 2021-06-13 | General Radio was a well respected US Electronics manufacturer for many decades. They manufactured many excellent products and if you are lucky you may have/ or have had one. But what is better than an excellent General Radio Product? How about a New Old Stock / Never used General Radio product? How does it get better?This General Radio 1454A is an excellent 4 decade Kelvin Varley Divider manufactured by GR some time in the early 1960's. I managed to purchase it still in a sealed box, a few years ago. All of the tags, wrappings, manual, brochures, etc. that would accompany a new piece of quality equipment are here still. I checked out the unit and found that the switch shaft lubricant had dried out, and I had to re-lube the shafts. But, after that the unit tested out flawlessly!In this video I give you a look at it, and use it to divide down a 1v reference flawlessly to various 4 digit combinations. It is to be sold in all of it's original packaging, double boxed to preserve it.
Sony UP811 Thermal Video Printer bap8guy 2021-06-12 | This mid 1980's thermal video printer was developed primarily for medical use, as a printer for ultrasound imaging and it was a breakthrough design. Using thermal printing on special thermal plastic paper it provided excellent print quality for the time.I received this unit as a part of a larger lot of equipment I purchased and have had it setting around for several years waiting for me to experiment with it. In this video I demonstrate that it still puts out a pretty decent image from any composite video device (usually they have an RCA video output jack). I connected an RCA video camera from the 90's to it through an RCA to BNC connector and BNC cable. Turned the unit on, loaded the paper, set it for a frame grab print and hit the print button! Did it work? Please see the video!A unit like this could print from a composite video output from various video units, or maybe an oscilloscope, in order to record on paper your events.
General Radio 1419M bap8guy 2021-06-11 | This 3 decade capacitor has been repaired utilizing capacitors with voltage ratings higher than 500v (most were 630v), so not only is it now well within specs for capacitance, it is so while maintaining its voltage ratings.In the video I test the unit, record the results and then go over them off of the computer. It easily passed the performance test. It is in excellent condition, operates very smoothly and looks like a really fine piece of gear (which it is).
Shallcross 8315 Decade Resistor bap8guy 2021-06-11 | These are the internal resistors and circuitry for the Shallcross 8315 Decade Resistor. It is a 6 decade unit, spanning 0 to 111,111 ohms in .1 ohm steps!The resistors are rated at at least 1/2 watt per step.
Fluke 8810A 5 1/2 digit bap8guy 2021-06-10 | A Fluke 8810A, 5 1/2 digit DMM, with Ohms and True RMS AC options, tested on video.
Gertsch RT-7 AC Voltage Divider bap8guy 2021-05-29 | This is a very heavy duty, high precision, high linearity AC Voltage Divider, usually known as a Ratio Transformer. Their linearity is known to be better than .0001%! They are extremely useful for providing several decades of dial select-able voltages from a single, stable low distortion voltage in.In this video I introduce you to the device then I connect it to a 1v source and later to a 10v source and then utilize the decade dials to provide my desired voltages down even to the microvolt!
General Radio GR1419M Decade Capacitor bap8guy 2021-05-02 | This unit was probably made in the 1960's, from a basic design of the 1950's. It is ruggedly built, but was the economy model of it's day (but extraordinarily expensive in today's money). I wanted a better capacitor standard for my bench and found this one at a good price. Physically it is in great shape, however the 3rd decade (.1mfd per step) was off an average of 3%. I found on the internet that it was expected to be within +/-1.5%, and that the capacitors were paper/wax. So, I figure the capacitors have aged and drifted in value, so I decided to replace them. In the video I show the internals, discuss what I will do, perform the repair and then test the results. The final results show my efforts were not in vain, as my mesurements are all under 1%, with the average at about .6%!I wound up with a nice bench standard.
VIZ WP705 50v 2A Current/Voltage Adjustable Digital Meter Power Supply bap8guy 2021-04-23 | This VIZ WP705, is a linear transformer based power supply that is capable of both Voltage and Current control adjustments. It was very special at the time of it's introduction, because it had two digital meters monitoring the units parameters. These were expensive and rare. So, as an additional feature, VIZ made these meters available for use as additional voltmeters to the user, capable of up to 99.9volts! It ran about $325 in the late 70's/early 80's, making it quite expensive. In this video I walk you around the unit, demonstrate it's capabilities and prove that it is still capable of it's functionality. Because of the arrival of an 150w current controlled electronic load, I was able to demonstrate this clearly!It is a decent looking quite, linear, transformer based 50v 2A Voltage/Current controlled capable Bench Unit!
Keithley 191 bap8guy 2021-04-22 | This Keithley 191 is in exceptional physical shape! This beauty is likely from between 1979 to 1983, but to look at it and to see it function, you would hardly believe it's age!It is a 5 1/2 digit, 200,000 count, manual ranging, that came standard with DC Volts & Ohms, but this one has the AC volts option as well! It can measure from 1microvolt to 1200 volts DC in 5 ranges, with up to 6 digits available. It does either 2 wire, or 4 wire ohms measurements from 1 milliohm to 20 megohms in 6 resistance ranges. With it's AC option it is capable of measuring from 10microvolts to 1000v AC in 4 ranges. It has 6 large 1/2 inch easy to read digits and has a push-button null that eliminates potentiometer zeroing, corrects for 2 wire lead resistance, and more.I will utilize the performance evaluation charts from the manual to demonstrate it's conformance to it's specifications. The results will be tabulated and you will see that it is still an excellent performer!
B&K 1650 Tri-Output Laboratory Power Supply (U1) bap8guy 2021-04-22 | This particular unit was built about 1983 and was popular for a few reasons. First, it had a 5v 5amp output that could power a large number of TTL related circuits, which were very popular at the time. Regulation on this supply is better than 3% at 5amps. The ripple and noise is less than 10mv for the 5v supply.Second, it had two independent 0-25v 0-.5amp power supplies regulated to better than .1% at .5A and with a ripple and noise level of better than 5mv. The two supplies (A & B) had isolated outputs, so they can be configured different ways. They could be used as independently adjustable supplies, they could be connected such that one of the supplies is negative, while the other is positive, with or without a shared ground. The two supplies could be setup so that Supply B is an adjustable % of Supply A's voltage and B will Track A (if A rises or lowers in value so will B) to better than 1%. The two supplies can be connected in series to provide up to 50v at .5amp, or in parallel (requires 2 equalizing resistors, see manual) to provide 0-25v up to 1amp. The outputs are overload protected and the meter can be set to read either voltage or current of A, B or the 5v supply.This makes the 1650 a very nice choice for supplying a breadboard with voltages for TTL, or Analog circuits.
Dana 5900 U2 5 3/4 Digit Voltmeter bap8guy 2021-03-27 | This Dana 5900, from the latter 1970's is a 5 3/4 digit, upgrade-able DVM, in beautiful working condition. The 5 3/4 digits refers the the maximum reading on any range. What they mean is there will be 6 digits maximum as long as the 1st 2 significant digits do not exceed the digits 16. So, on the .1v scale, you can read .000000v to .160000v. On the 1v scale you can read 0.00000v to 1.60000v, 00.0000v to 16.0000v on the 10v scale, 000.000v to 160.000v on the 100v scale and 0000.00 to 1000.00v on the 1000v scale (1000 is the maximum input).There are 5 DC ranges available .1v, 1v,10v,100v and 1000v. The ranges are manually selectable, or the unit can be placed in Auto, for automatic range selection. Polarity is indicated on the unit. There is a rate control (lower left of the front panel) that determines the cycle time for update, and as such it can be a "hold" control for readings. The base unit has an analog output available on the rear of the instrument, that uses 0-20v to represent the input measurement. A J201 connector on the rear allows for optional printer use, or for BCD output. This is an attractive unit, with big (.4 in) red easy-to-read digits. it has a nice wire stand for angled viewing. The red lens is scratch free. The controls work freely. In this video, I introduce the unit, then compare the bottom and uppermost range voltage readings to that obtained on a recently calibrated HP34401 6.5 digit DMM. The results are excellent!This unit will be sold with a Dana 5900 Operation / Service manual on CD.
AN3100 u7 4 Decimal Place Secondary Standard - Modified for 5th place bap8guy 2021-03-24 | This is the 2nd of 3 units I have modified to have zero offset. It is also the last for sale, as I am keeping one unit for now.The voltage standard was repaired, cleaned, painted, calibrated, and then modified to obtain zero offset. This has the effect of adding a 5th place, where zeros predominate. This video lets you view the testing of the unit, to observe and record the test results. The unit passed magnificently.
General Radio 1490-B Precision Decade Inductor bap8guy 2021-03-23 | This precision unit can provide measured inductance in 1 millihenry steps from 0 to 11.11 Henrys. They are becoming rare to the general consumer and equivalent units can cost thousands of dollars on today's markets. General Radio was an electronics manufacturer with a reputation for making fine precision electronics equipment for many decades. Today a company named IET Labs carry's on the manufacture of some of General Radio's product line. The 1491-D, a very similar device manufactured by IET, starts at about $13,000.There are 4 decades of inductance, dial select-able, on the unit. Each decade is capable of limited current capacity and each has an expected accuracy. The lowest range is 1 millihenry per step, up to 10 millihenrys, can handle up to 3 amps and has an expected accuracy of +/-2% or better. The 10 millihenry per step decade, up to 100 millihenrys, can handle 1 amp maximum, and has an expected accuracy of +/-1% or better. The 100 millihenry per step decade, up to 1000 millihenrys, can handle 300 milliamp max, and has an expected accuracy of +/- .5% or better. The 1 Henry per step decade, up to 10 Henrys, can handle 100 milliamps max, and has an expected accuracy of +/- .25% or better. These units are used as standards for testing measuring equipment, in the design of electronic filter devices (low pass, band pass, high pass types), and more. The wide range of select-able inductance makes it a natural as a test substitute for parts during the design phase.The 1490-B was known for it's high Q storage factor, toroidal construction that minimized mutual inductance and reaction to external magnetic fields, and excellent electrostatic shielding used in it's manufacture. They used the state of the art Molybdenum Permalloy Powder cores that provide the maximum Q and lowest core losses. These cores are highly stable with respect to temperature and ac flux patterns and have the widest range of permeability.I this video I introduce you to the unit and then utilize a modern LCR device to measure the inductance of each step of each decade. The measurement device is a DER EE DE5000, which is capable of approximately 1% accuracy (or better) in the measurement of these inductances. The results were tabulated on a spreadsheet and the unit analyzed for % accuracy (within capability of the LCR device). The results showed that the unit provided better than 1% accuracy on all but the 100 millihenry per step decade, where the results were better than 1.5%.
Pioneer SX-850 bap8guy 2021-03-03 | A classic vintage receiver (produced in the late 1970's), this unit is also in spectacular shape! Big (20 3/4" W, 6 13/16" H, 16 3/16 D) and heavy (42lb 30z) and beautiful, this behemoth cranks out 85W per channel RMS into 4 ohms (with both channels driven together), or 65W per channel at 8 ohms. At full rated power the spec says less than .1% Thd and at 33W that figure drops to less than .05%Thd! It comes with two magnetic phono inputs, 3 tape player inputs, a microphone input, and an Aux input (for CD etc). I opened up the unit, carefully brushed and vacuumed out the interior, then cleaned and lubricated the controls to remove the "crackle" often heard with dirty dried out controls. Then I put it back together, oiled the wood, cleaned the cabinet and tested it out (also made a video). Some Ebay HiFi enthusiast will be a lucky bidder!
Scam Power Saver SD001 bap8guy 2021-02-22 | I redid this video to improve its quality.My wife surprised me with a pair of Power Saving boxes, model SD001, that I recognized as a SCAM. I decided to open them and analyze them and share the video. Instead of saving power, these devices use power, to light two little lights that tell you its plugged in. Other then that, they do nothing.
Analogic AN3100 modified for Zero Offset - gets additional Decimal place of Accuracy!!! bap8guy 2021-01-22 | This Analogic An3100 was repaired, calibrated, tested and verified working. Then, it was modified (with the assistance of a retired ex chief engineer from Analogic) to provide an overall Zero Offset adjustment capability. The unit was modified, calibrated, tested and verified working, and... if gave an additional decimal place in accuracy!!!This video shows the measurement of each step of each of the 5 decades, but the output is measured on a recently calibrated HP34401A to 5 decimal places (not 4). The results are tabulated and the error calculated and compared to the original specification of .005% +/-50 microvolts. The results prove the accuracy of the additional decimal place.
.5Mhz to 1600Mhz Wideband Ampllifier bap8guy 2020-09-30 | In 2014 I bought a wideband amplifier module for about $50. It was reported to have a bandwidth ranging from 500Khz to 1600Mhz, could produce an output of 10dBm (10 milliwatts) and provide as much as 30dB of gain (gain of 1000)!It required 12 volts to operate, and needed a shielded input and output. It was also small enough to fit in one of my project boxes. I had a 12 v "wall wart" power supply and a nice lighted push switch on hand. I ordered a couple of 8" BNC female to SMA male RG58 adapters for the input and output. So, I cobbled together a wideband amp for my bench!I have a number of decade attenuators on my bench that could control my input or output as needed (for gain control). It was a simple, yet effective project for my bench!I have checked and no longer see my exact module available, but I have found a number of modules as cheap as $5 that report to be just as capable! Perhaps you might want to build one?
Volt Amp Watt Meter bap8guy 2020-09-30 | This Volt-Amp-Watt meter was purchased off of Ebay for about $10. It reportedly can handle up to 100 Amps and 0-60volts. In the video I show how simple it was to install into a box, provide a power switch and plug, mount the terminals to the box and ...voila! You have a nice monitor for your experimentation!
2 4Ghz Frequency Counter bap8guy 2020-09-30 | There are modules available on Ebay that for about $10 to $18 claim to be complete frequency counter modules capable of covering 100Khz to 2.4Ghz! I bought one of these units and cobbled together this simple project. A box, 12 v "wall wart" style power block, switch, power jack and input jack is all that is needed for parts. Then a few hours of you time to fabricate.In the video I give you a look outside and inside of the unit, then I test it! It is a capable unit.
10 0000v ref bap8guy 2020-09-30 | I frequently find the need for a very accurate and stable voltage reference (10v is a good ref) for use in calibration of another device or to supply the reference voltage to a KVD divider, or other such project. Finding a 10v reference that is stable and accurate down to 10.0000v is not that easy to come by. However, for a few dollars and a few hours work, you can build one. You will need a good DVM capable of measuring down to better than the 100microvolt level, to keep the unit calibrated. And it will be necessary for you to provide a calibration hole on the unit that is handy, as calibration will be needed each time you intend to use the device. It will hold the calibration for several hours to the fourth decimal place, and days to weeks to the 3rd.
