Le labo de Michel
LDM #285: Bendix Polar Path Compass Coupler - Part 1: Teardown
updated
00:00 - Intro
01:43 - Teardown
06:13 - Dual synchro system
06:48 - Reverse engineering : dual synchro system
08:44 - Static Source Error Correction (SSEC)
11:35 - Mach number computation and SSEC cam
14:29 - Output synchro and digitizer
15:22 - Servo monitor circuits
Schematic diagram:
https://mwblog.fr/wp-content/uploads/2024/10/CPU-46.pdf
01:01 - Teardown
04:09 - Electronic boards
06:43 - Electronic time interval generator
13:30 - Programming panel
15:58 - Analog boards
00:00 - Intro
01:11 - Teardown
02:13 - First analysis
04:17 - Electronic boards
05:29 - Reverse engineering
07:40 - Test coils
08:46 - Faulty detector
11:05 - Bypassing the faulty detector
11:23 - Test
This videos shows technical details about a Russian servo accelerometer ДЛУММ-30 (DLUMM-30). This accelerometer was installed inside a 9E420 radar seeker.
How it works:
A mass translates the acceleration into a torque which is balanced by a second torque generated by two coils. A sensitive zero detector detects any deviation of the moving mass from the zero position. The resulting voltage is amplified and fed to the torque generator, keeping the mass at the same zero position.
The zero detector uses two variable transformers. The primaries are supplied with an ac voltage at 830 kHz. A small piece of copper mechanically linked to the moving assembly penetrates between the primary and the secondary, which modifies the differential induced voltage.
Schematic diagram:
01:00 - Draining the damping oil
02:04 - Opening the gyro
03:48 - Torque motor
06:44 - Test setup
07:28 - First test
00:00 - Intro
00:40 - Teardown
02:45 - Power Supply board
03:15 - Servo Amplifier board
03:31 - Fuel flow rate and logic board
05:58 - Test
08:45 - Reverse engineering - Part 1: analog display
10:25 - Digital input circuit
11:44 - Gate and averaging circuits
13:11 - FF rate and display update rate
15:51 - Counters reset signal
16:24 - Scrolling detection
17:40 - Counters and display
19:34 - Clock generator
Connector pinout:
A-B: Lighting, 5Vrms
D-K: 115Vac 400Hz
J: input common
H: analog input, 0 to 5V
C: digital input, 2.27Hz square wave for 1,000. Display proportional to input period. Hi level 6V min.
How it works:
There are 2 two separate inputs. The first one is a DC voltage from 0 to 5V which permits to set the needle between 0 and 12,000 kg/h. Its uses a torque motor with an embedded potentiometer for the feedback. A servo amplifier permits to set the needle according to the input voltage.
The second input is a square or rectangular signal. The clock signal is fed to three CD4518 counters gated by the input signal. An averaging of 10 is performed by counting 10 input cycles and by dividing the counts by 10. A the end of the counting a load signal permits to update the coding wheels display.
The display rate depends on the rate of change of the fuel flow. A differentiator is used to get an image of the variation of the fuel flow with time. This signal is fed to a Voltage Controlled Oscillator which gives the maximum update rate of the display.
The rightmost digit scrolls when there is a variation of the fuel flow.
Schematic diagram:
https://mwblog.fr/wp-content/uploads/2024/09/Jaeger_FF_Indicator_A.pdf
The second episode will show the code disassembly and I hope the complete test of this unit using an ARINC429 test generator.
00:00 - Intro
01:05 - Teardown
02:54 - Interface board
03:35 - MPU board
04:57 - Power supply and stepper motors driver board
06:43 - Display board
07:40 - Preliminary test
10:15 - Display test
Reverse engineering:
10:50 - MPU board
12:27 - ARINC429 Interface Board
15:50 - Luminosity control
17:39 - Power down detection
18:15 - Display board
Schematic diagram:
https://mwblog.fr/wp-content/uploads/2024/08/B727-EPR-A.pdf
Blog:
https://mwblog.fr/ldm-375-boeing-727-epr-indicator-part-1-teardown-and-reverse-engineering/
00:00 - Intro
00:40 - Teardown
03:34 - First test and gyro precession
04:50 - Final test with magnetic compass and Collins HSI
Reverse engineering:
06:32 - Part 1: overview
07:12 - Part 2: power supply
07:44 - Part 3: inner gimbal horizontal stabilization
08:48 - Part 4: input filter
10:53 - Part 5: amplifier and phase detector
12:29: Part 6: high speed slaving
13:27: Part 7: reference signals generator
HSI Collins 331A-8K:
youtu.be/E4v6DHBhFQs
Schematic diagram :
https://mwblog.fr/wp-content/uploads/2024/08/DG11-0105-1.pdf
Blog:
https://mwblog.fr/?p=804&preview=true
This board is probably involved in the servo control of the antenna position.
00:00 - Intro
01:57 - Inside the shield
02:47 - Reverse engineering
04:07 - Attenuators
04:36 - Amplifiers and bad guarding tracks
05:44 - Analog switch control
05:58 - Colpitts oscillator
07:15 - Oscillator test
Schematic diagram in pdf: https://mwblog.fr/ldm-373-analysis-of-a-kh-101-missile-electronic-board/
00:00 - Intro
00:05 - Fiber Optic Gyroscope ТИУС500 (TIUS500)
04:28 - Tornado-S IMU
06:35 - Reverse engineering - photodiode amplifier & ADC
07:07 - Reverse engineering - phase modulator circuits
07:39 - SLED temperature regulation
10:16 - SLED light power regulation
11:48 - System ADC
First part:
youtu.be/Ac2ioGwfsbI
Schematic diagram and blog:
https://mwblog.fr/ldm-372-fiber-optic-gyro-and-tornado-s-missile-gyro-assembly/
00:38 - Teardown
05:21 - Test
08:01 - Piecewise amplifier
11:30 - Reverse engineering
11:41 - Power Supply
12:10 - Reference voltages
12:35 - Main circuits
13:00 - Front-end amplifier
14:21 - Piecewise Amplifier circuits
Connector Pinout:
1-2: Lighting 5Vrms
3-4: 115Vac 400Hz
5: Thermocouple (-)
6: Thermocouple (+)
7: Mechanical ground
00:00 - Intro
01:17 - Teardown
02:29 - EGT board
04:05 - Cold junction compensation
05:37 - EPR board
06:47 - N2 board
08:27 - N1 board
08:45 - Tests
11:34 - Self-test
12:00 - Reverse engineering: PS board
12:39 - Reverse engineering: EGT board
16:49 - Reverse engineering: N2 board
Links:
Sensor datasheet:
mouser.com/datasheet/2/589/SM5812-254991.pdf
Part 1:
youtu.be/PI8aGYTlvJQ
00:00 - Intro
00:05 - Board overview
01:50 - Preliminary test
02:27 - Reverse engineering
03:36 - Test
Notes:
This link shows a transmission format identical to the messages sent by this air data computer:
wokwi.com/projects/374500929580971009
Blog and schematics:
https://mwblog.fr/ldm-369-shahed-136-drone-air-data-computer/
00:00 - Intro
00:56 - Teardown
02:25 - No gear train
02:50 - Test
05:53 - Attitude circuits modular circuit
Notes:
* This ADI uses a DC motor for the roll control and a torque motor for the roll
* There is no gear train, the motors are directly linked to the gimbal for the roll and to the sphere for the pitch. This permits to save some weight and cost, the counterpart is the lack of stability when quick change of pitch or roll accurs. However this shouldn't be a problem with commercial aircraft.
* The electronics use mainly potted modules
Pinout:
26-27-28: roll synchro input
29-30-31: pitch synchro input
10: 28V attitude enable signal (from vertical gyro)
00:00 - Intro
01:46 - Teardown
02:36 - Electronic board
03:16 - Test
06:15 - Reverse-engineering - overview
06:47 - Reverse polarity protection
08:15 - Power supply
08:54 - Brushless motor power stage
10:03 - PWM input interface
10:27 - Feedback device
10:46 - Feedback output circuit
active parts used:
SED10070GG: N-channel MOSFET (x7)
lcsc.com/datasheet/lcsc_datasheet_1912111437_SINO-IC-SED10070GG_C396083.pdf
SGM8591: Single-Supply, Single Rail-to-Rail I/O Precision Operational Amplifier
sg-micro.com/rect/assets/c8325911-0f35-4c14-a4b8-98828013d197/SGM8591.pdf
EG2134 芯片用户手册 三相独立半桥驱动芯片
lcsc.com/datasheet/lcsc_datasheet_2304140030_EG-Micro-EG2134_C480661.pdf
TLP2361
eu.mouser.com/datasheet/2/408/TLP2361_datasheet_en_20151102-1079441.pdf
XL7005A - 0.4A 150KHz 80V Buck DC to DC Converter
lcsc.com/datasheet/lcsc_datasheet_1811081614_XLSEMI-XL7005A_C50848.pdf
Blog with schematic diagram in pdf:
https://mwblog.fr/ldm-367-shahed-136-kamikaze-drone-servomotor/
Link to schematic diagram:
https://mwblog.fr/wp-content/uploads/2024/06/LDM367-Shahed-136-servomotor_B.pdf
The servo is similar to the giant scale servo from Hitec ref HS-1005SGT:
hitecrcd.com/products/servos/digital/sport-giant/hs-1005sgt-industrial-grade-giant-scale-servo/product
00:19 - VG1000J unknown part (actually VQ1000J)
01:46 - Schematic diagram overview
02:38 - Power supply
04:31 - Modifications for 115/230V 50/60Hz
07:07 - AC-DC converter assy
08:03 - Temperature controller
10:22 - Crowbar circuits
11:42 - Logic circuits
14:28 - Capacitive probe fontend
Notes:
The supposed VG1000J is actually a VQ1000J:
vishay.com/docs/70226/70226.pdf
Blog:
https://mwblog.fr/ldm364/
00:00 - Intro
01:26 - X-ray analysis using XYLON Cheeta EVO
04:07 - Preamplifier
07:53 - Complete schematic diagram
08:39 - Modulator
Merci à la société Inovelec pour avoir consacré un peu de temps à l'inspection aux rayons X de ce module, ce qui m'a permis d'effectuer la rétroingénierie de celui-ci.
inovelec-groupe.com
Other episodes:
youtu.be/Y11XXXc7LKY
youtu.be/_EgoEV346tY
00:00 - Intro
00:45 - Front panel
02:29 - Heaters and possible modifications for 115/230 50/60 Hz
05:18 - Electronic boards
00:03 - Outer gimbal synchro test
01:02 - Inner gimbal synchro test
02:00 - Slip ring contact pinout
04:48 - Gyro rotor spinning test
00:00 - Intro
03:25 - Teardown
05:51 - Draining the oil
08:48 - Gimbals resolvers and torque motors
One board contains an Atmel ATMEGA168 micro-controller which is connected to a MEMS rate gyroscope and one MEMS accelerometer. The gyroscope is soldered on a small pcb which is mounted on a small mechanical assembly. The angle of the gyroscope can be adjusted using two screws.
Another board permits the servo control of the position of something linked to a brushless motor.
00:00 - Intro
02:04 - Gyro and accelerometer processing board
04:45 - Interface / DSP / CPU board
03:36 - Brushless motor servocontrol
05:39 - Reverse engineering: MEMS Gyro assembly
06:04 - MEMS Accelerometer
06:28 - Microcontroller Atmega168
07:12 - Ribbon cable interface
08:04 - Servo control board overview
08:49 - MC33035 Brushless DC motor controller
10:15 - DAC circuits
11:27 - Summing amplifier and phase correction
12:47 - Absolute value circuit
We can can this receiver in a Tornado-C missile for instance (Торнадо-С).
Video: youtu.be/xJyV7AGPT_4?si=R-ju1wXSOHIxuqTy&t=198
00:00 - Intro
00:04 - Overview
05:08 - Reverse engineering part 1: overall description
06:07 - part 2: 12V DC-DC converter
09:05 - part 3: voltage monitor circuits
13:14 - part 4: 3.3V and 5.0V DC-DC converters
13:57 - part 5: DC-DC converters shutdown circuits
16:00 - part 6: standby power supply
Errata:
Due to an error during reverse engineering the networks Diode-Resistor-Capacitor are actually snubbers connected in parallel to each transformer primary. Nothing is connected to the gate of the MOSFETs.
Notes:
Most parts are US or European parts. It is obvious that Russia don't have the modern technology to design such board with their own parts.
Russian parts:
* The toroidal transformer
* The 10A fuse
* Maybe the electrochemical capacitor
Main parts used on this power supply:
* UCC28084 (Texas) PWM controller for the 12V power supply
* TPS54356 and TPS54357 (Texas) PWM controllers for 3.3V and 5V Power Supplies
* MAX974 (Analog Devices) Quad comparators with internal voltage reference
* IRF7328 (Infineon) dual P-channel MOSFET
* MJD112 (ON Semi) NPN Darlington
* FDS4488 (On Semi) N-channel MOSFET
* IRFR5305 (Infineon) P-channel MOSFET
* SI4156 (Vishay) N-channel MOSFET
Weird things:
* The grid of one unused MOSFET is left open
* What is the purpose of the fuse ? What will happen to the missile if the fuse blows ?
If someone knows something about this device please let me know, particularly the purpose of the various controls on the front panel.
00:00 - Intro
03:54 - Teardown
05:16 - Disc & Ball integrator
07:33 - Mileage computations
13:44 - Normal / Fix modes
15:16 - Synchronous motor
16:14 - Test with manual heading change
17:26 - Mileage simplified electro-mechanical diagram
Notes:
- At that time the goal of the third disk and ball integrator (on the bottom side) is unknown
Edit 07/03/24: according to @Pulsynetic the disk and ball integrator is used for a cosecant function which permits the correction of the meridians convergency to give the longitude.
- On the simplified electro-mechanical diagram the outputs of the disk and ball integrators are not the latitude nor longitude but the E-W and N-S mileages.
Mileages computation:
The mileages are computed using two disc and ball integrators. The disc of each integrator is linked to the same M-type stepper motor. The frequency of the signals which drive the motor must be proportional to the ground speed.
The input of the integrator (the displacement of the balls) is an image of the sine and the cosine of the heading. This is simply done using slides and levers linked to the heading shaft.
The angle of the output shaft is therefore an image of the integral of V(t)*sin(Theta(t)) and of V(t)*cos(Theta(t)), that is to say respectively the mileage on each axis.
Links:
Dead reckoning on Wikipedia:
en.wikipedia.org/wiki/Dead_reckoning#:~:text=In%20navigation%2C%20dead%20reckoning%20is,course)%2C%20and%20elapsed%20time.
Disc and ball integrator on Wikipedia:
en.wikipedia.org/wiki/Ball-and-disk_integrator
on YT:
youtube.com/watch?v=s1i-dnAH9Y4&t=1853s
Other navigation computers on my channel:
youtu.be/cUOpCMj17Cw
youtu.be/cpOrcHsgwJY
youtu.be/TJI_owLNPZg
Ball resolver:
youtu.be/SKPPBgBhxNs
THE V-FORCE : 1955 to 1966
http://www.blackmanbooks.co.uk/navigation.html
Book Computing mechanisms and Linkages by ANTONÍN SVOBODA (1965)
randomwraith.com/documents/Svoboda-ComputingMechanismsLinkages.pdf
00:00 - Intro
01:31 - MPU13P board
04:02 - Text strings from EPROM "PRGS 1/2" dump
04:15 - Text strings from one EEPROM X28HC256
04:20 - Second board teardown
05:24 - Third board teardown (UPP20)
07:19 - Front assembly
08:56 - DC-DC converter
00:00 - Intro
01:24 - Teardown - Electromechanical assembly
03:48 - Electronic boards
08:24 - Schematic diagram from reverse engineering
09:31 - EPR test
About EPR:
https://skybrary.aero/articles/engine-pressure-ratio-epr
00:00 - Intro
00:25 - Optical sensor from X-101 missile
02:30 - 3-axis Fiber Optic Gyroscope (probably from Tornado MLRS)
Links
A picture of the first sensor with the optics:
photo.unian.info/photo/1173510-optiko-elektronnaya-sistema-korrekcii-starogo-obrazca-rakety-h-101
Several viewers have found the technical documentation of the Fiber Optic Gyro:
http://www.optolink.ru/documents/trs-500_RU.pdf
Other information concerning the FOG:
en.defence-ua.com/industries/the_life_of_american_astronaut_depends_on_the_intel_chip_from_aliexpress_used_in_russian_rocket_for_tornado_s_mlrs-6320.html
Technical documentation in russian:
https://ela.kpi.ua/bitstream/123456789/30573/1/Stranskyi_magistr.pdf
00:00 - Intro
01:14 - My French accent
03:13 - Nice boards
04:03 - Is it legal to post this on YT ?
05:01 - SRAM dump ?
06:24 - Powering-on the boards ?
06:42 - Is it legal to own that thing ?
07:06 - Sensor
07:56 - ITAR
09:16 - Prototype ?
09:48 - Vias
09:59 - Power op-amps and fins control
recorded 2023/12/02
Nota 2023/12/24: this video is intended to show the technology now obsolete used in the 80s-90s on military devices. Similar technology can be found in avionics for instance. On that guidance section there is nothing sensitive, it is just a complex CPU board with golden parts.
00:00 - Intro
04:09 - Teardown
06:28 - Electronic assembly
10:18 - Sensor
Links:
TOW Missile:
youtu.be/s7-6hgX7-zQ
youtu.be/5wKB3bmq1fM
Maverick Missile Seeker:
youtu.be/7dBfYFNp7CM
youtu.be/aCOK3-KvMoE
00:00 - Intro
01:00 - Teardown
02:08 - Input filter
06:08 - FI preamplifier
08:00 - Mixer
10:48 - Servo control feedback potentiometer and reflector voltage setting
13:52 - Motor
15:38 - Frequency setting test
16:34 - Schematic diagram
Technical description:
It uses a 1N26 mixer diode and a 2K48 reflex klystron for the local oscillator. Frequency setting uses a DC motor and several devices linked to the output shaft:
* A fixed cam permits to modify the frequency of the reflex klystron.
* An adjustable cam permits to change the central frequency of the input filter
* A potentiometer permits to change the reflector voltage of the klystron according to the frequency
* Another potentiometer is connected to the connector, probably for the servo control of the frequency setting mechanism.
* A synchro transmitter
* An internal indication of the frequency using coding wheels
Links:
Klystron 2K48:
http://lampes-et-tubes.info/mwkl/2K48.pdf
Recorded 2023/10/31
00:00 - Intro
01:53 - Electro-mechanical assembly
04:13 - Electronic assembly
The first part of this video shows the teardown followed by the test of this instrument.
The second part is more theoretical, the general functioning of this unit is explained as well as some particular topics.
00:00 - Intro
00:40 - Teardown
01:11 - Electro-mechanical assembly
07:22 - Electronic assembly
10:37 - Test
15:52 - Air Data Computer ARINC565 Dual Speed Synchro
18:32 - Altitude Alert - General functionning
24:48 - Synchro, resolver, transolver and differential resolver
33:33 - Coarse window generation
36:48 - Synchro transmitter presence detection
38:30 - Detailed schematic from reverse enginnering
Recorded 2023/10/23
00:00 - Intro
01:05 - Teardown
06:03 - Non-linear scale
08:21 - Tests
09:34 - ARINC 552
11:00 - Reverse Engineering Part 1: Main circuits
14:11 - Reverse Engineering Part 2: Flag circuits and power supply
15:40 - Reverse Engineering Part 3: Decision Height circuits
Technical details
This Radio Altimeter is compliant with ARINC 552 standard.
The servo control loop uses a potentiometer for the feedback and a DC motor for the drive of the tape. The input is a differential DC voltage. The error voltage (feedback voltage - input voltage) is fed to the servo amplifier. The servo amplifier has a special feedback which permits to compensate partially the series resistance of the DC motor. This permits to have a control of the speed of the motor which permits a damping of the control loop.
Connector pinout:
A-B: 26Vac 400Hz
L : signal ground
Y : signal input (+)
Z : signal input (-)
a-L : Test push button
D-g : 5V lighting
e-f : relay contact for decision height (closed when the altitude is below the DH)
Useful links:
Burr-Brown document: Control a DC Motor without Tachometer Feedback
ti.com/lit/an/sboa043/sboa043.pdf
00:00 - Intro
01:02 - Teardown
05:34 - Test
Technical details:
- The vertical speed needle is driven using a synchro receiver
- A servo control is used for the altitude. One complete revolution of the synchro corresponds to approximately 25,000 feet.
- Not shown on the video: the triangular screw one can see on the bottom of the front panel permits to adjust the zero altitude by rotating the body of the synchro control transformer used for the servo control.
- The solenoid used for the flag seems activated by a motorized potentiometer. I didn't test this feature.
02:22 - ARINC 465 Standard
02:40 - Dual speed synchro
03:58 - Teardown
05:33 - Test
07:49 - Flag circuits
08:29 - Flag test
00:56 - Teardown
02:34 - Reverse Engineering Part 1: Stepper motor driver
04:39 - Reverse Engineering Part 2: Power supply
05:30 - 60Hz quadrature generator board
06:30 - quadrature generator board test
06:39 - Final design and test
00:00 - Intro
01:19 - Teardown
10:08 - Test
00:00 - Intro
00:37 - Teardown
03:04 - Preparation for reverse engineering
04:17 - Reverse engineering part 1: power supply
05:33 - Reverse engineering part 2: main circuits
07:20 - Issue #1: wrong transistor orientation
09:15 - Issue #2: cracked solder joint
10:11 - Test
Note about the construction: the electronic side of this indicator was poorly constructed. The dual layer non-plated through hole PCB without solder mask nor conformal coating has resulted in a solder joint crack. Someone attempted to repair this instrument (maybe because of this issue) and one 4-pins Darlington transistor was not fitted correctly during this repair.
Internal circuits: the input signal is fed to a comparator which delivers a square wave signal. This signal is fed to a discrete monostable which delivers a rectangular signal. The duty cycle and therefore the mean value is proportional to the input frequency. After filtering the DC voltage created is used as the input of a servo control loop. The feedback device is a potentiometer. A chopper using two dual emitter pnp chopper transistors converts the DC error voltage into an AC error voltage which is fed to the servo amplifier which drives the AC motor.
This instrument incorporates an inverter for each channel for the generation of the AC voltage required by the motor.
The use of an AC motor and the choice of a DC power supply voltage complicate dramatically the circuits of this instrument.
Particular parts used:
Dual emitter PNP chopper transistor: Sprague 460070-2
Servo amplifier power stage and inverter: Darlington U2T101
Pinout from reverse engineering:
(x): left engine
A (K): input signal (5Vpp min, positive signal), 70Hz for 100%
B (F): common line for power supply and input
C (E): positive power supply (14 or 28V, automatic selection by the unit)
About bipolar chopper transistors and circuits:
http://www.bitsavers.org/components/motorola/_appNotes/AN-0470_Bipolar_Chopper_Transistors_And_Circuits.pdf
Recorded 2023/07/23
fr.wikipedia.org/wiki/Intertechnique
00:00 - Intro
00:55 - teardown
03:36 - Reverse engineering part 1: power supply
04:49 - Reverse engineering part 2: dimmer circuits
06:13 - Reverse engineering part 3: analog board
07:04 - Test
Connector pinout:
A: ground
B: negative power supply -20V
C: positive power supply +20V
D: input voltage (1 to 5V with 5V reference voltage)
E: reference voltage input
F: ground
H: 82 ohms to E
J: digital ground (connected to analog ground through two diodes back to back)
T-U: lighting (0 to 5Vrms 400Hz)
Technical description:
- The input voltage is fed to a 10-bits ADC made with a 4040 counter, one 10-bits DAC, two comparators and one JK flip-flop.
- The 5V power is an SMPS which uses a classic SG1524 configured as a step-down DC-DC converter.
- Display value is 0 for 1V input voltage and 5V reference voltage
- Display value is 9900 for an input voltage equals to the voltage reference
- The rightmost digit is always 0, fuel quantity displayed is XXX0 pounds
- This instrument requires two power supply voltages: +20V and -20V.
- There is a dimmer circuit which permits to attenuate the display luminosity according to the level of the lighting voltage.
- The refresh rate is approximately 2 seconds.
- The display is blank if the reference voltage is below 2V
- The display is blinking if the lighting voltage is not present
00:35 - Teardown
01:45 - How it works
01:52 - Reverse engineering
03:31 - Repairing the coil
04:03 - Open loop test
04:53 - Closed loop test
Links:
LDM #169: Aircraft Servo Potentiometer Type 6A/4725 Teardown and Tests
youtu.be/_i8dZ0o0ZIs
03:28 - Roll stabilization mecanism
05:35 - Pressure switch
06:52 - Internal assembly
07:50 - Gyro unit
09:39 - Rotorace gyro
11:05 - Gyro
11:30 - Test
LDM #349: Blackburn Buccaneer height and rate of climb indicator (beginning from 2023/11/17)
youtu.be/4Fg5cnIGl-U
00:50 - Teardown
04:47 - Torquer test
05:55 - Reverse engineering part 1: frequency to voltage converter
08:27 - Reverse engineering part 2: amplifiers
09:16 - Reverse engineering part 3: servo amplifier
10:05 - Test
12:02 - Charge balance frequency to voltage converter - comment ça marche ?
17:20 - Comparison with actual measurements
00:30 - Servo amplifiers module
01:53 - Figuring out the pinout
02:57 - Test
04:21 - Opening the instrument
07:15 - What's inside the electro-mechanical assembly
Examples of EPR transducers:
youtu.be/QlEehvyJ-M4
youtu.be/kMyuKtHlHiA
youtu.be/KMIZj74kBrY
Other EPR indicators:
youtu.be/WhxyEzI6IF0
youtu.be/tN16HeZ750c
youtu.be/Dlsc9dlFBGI
This instrument requires an external AC voltage reference voltage for the feedback potentiometer (out of phase regarding input signal). This permits to have a display which doesn't depend on the instrument itself.
00:00 - Intro
01:54 - In search for power supply pins
04:48 - In search for input pin
05:47 - In search for flag pins
06:11 - In search for ground pin
07:34 - Preliminary test (open loop)
08:33 - Final test (closed loop)
Pinout:
A-B : Power Supply input 26Vac 400Hz
C : input common
D(-) E(+) : flag (28Vdc)
F-G : feedback potentiometer (2k)
H : input
The input is a negative DC voltage. The miles result is shown using a mechanical display activated by a stepper motor. The more negative the input voltage, the faster the counter advances.
The input voltage is fed to a VCO. The VCO generates a pulse signal with a frequency proportional to the negative input voltage. This clock signal is fed to the stepper motor driver circuits.
This indicator uses several smd DTL logic ICs and two op-amps for the VCO.
00:00 - Intro
00:34 - Teardown
01:37 - Electronic boards
04:11 - Reverse engineering - VCO circuits
05:13 - Reverse engineering - Stepper motor control
06:23 - Test
Op-amps (X2): SN524A
T flip-flop (X2): 994551 = MC945F
quad NAND gate (1X): D946
Connector pinout:
A: -6.4V reference voltage output
B: input voltage (must be negative)
C: common for input voltage
J-K: 5V for lighting
G-H: 26Vac 400Hz power supply
youtu.be/cpOrcHsgwJY
00:00 - Reverse Engineering
02:35 - Test
03:41 - Radar frequency estimation
Part 1:
LDM #336: RAF Avro Vulcain Electrical Indicator Type 101 - Part 1: teardown
youtu.be/cpOrcHsgwJY
Electrical Indicator Type 101 used for the Doppler radar system. It contains an air speed indicator, a drift indicator, a distance miles indicator, and a ground speed indicator using a bar graph.
This indicator uses plenty of sub-miniature and ultra-miniature vacuum tubes.
00:00 - Intro
01:20 - Teardown
03:21 - First power up
04:36 - Filters box
05:31 - Indicators
08:05 - Indicator repair
Part 2 (on line 2023/09/05):
LDM #337: RAF Avro Vulcain Electrical Indicator Type 101 - Part 2: Reverse Engineering and test
youtu.be/TJI_owLNPZg
recorded 2023/08/04
01:20 - Teardown
01:50 - Desoldered capacitor
03:52 - First test
05:15 - Repair
06:30 - Quick test with a solder iron
07:06 - Final test using a thermocouple simulator
This video shows the teardown, the repair and test of a Turbine Gas Temperature Indicator manufactured in 1986 by Intercontinental Dynamics.
The power supply and the needle command circuits are identical to the ones of the RPM indicator described in video #97:
youtu.be/aOXe8n5juoM
The input is a K thermocouple. Cold junction is present on the front-end board using 2 massive copper pieces. The voltage is amplified using two op-amps OP41 and converted into a digital data using a Teledyne 3-1/2 digit ADC TSC8750 with BCD outputs. This digital data is displayed on three 7-segments displays using three classic BCD to 7-segments drivers CD4511.
This digital value is also fed to the addresses of two EPROMs. The EPROMs contains sine and cosine tables which drive two 8-bits DACs DAC0800. Each DAC output is fed to a power op-amp LH0021K which drive a sine-cosine DC synchro which sets the needle.
alldatasheet.com/datasheet-pdf/pdf/98591/NSC/LH0021K.html
Pin-out of the rear connector:
G: 0V
F: 26VAC 400 Hz
E-D: lighting
A-C: K thermocouple input
Recorded 2023/07/29
00:00 - Intro
00:47 - Reverse Engineering Part 1: 400Hz sine oscillator
03:11 - Reverse Engineering Part 2: Output stage
04:02 - Reverse Engineering Part 3: Output voltage control circuits
05:16 - Modification for slave mode operation
06:08 - Slave Mode Test
07:38 - Modification for slave mode
08:28 - Phase shifter and final design
09:49 - Test
Link to part 1:
LDM #323: Aircraft Static Inverter EMP Electronics PS285: teardown and test
youtu.be/2xIdZvDX5XA
00:00 - Intro
00:41 - Teardown
01:49 - Searching for the pinout
03:22 - Test
This indicator uses a magnetic amplifier with two transistors for the servo control of the needle.
00:00 - Intro
00:15 - Teardown
03:03 - Reverse engineering
04:31 - Test