atkelar | HP 410C VTVM (as seen with @CuriousMarc ) - Part 2 @atkelar | Uploaded February 2024 | Updated October 2024, 57 minutes ago.
About two months ago, I was watching a restoration video by @CuriousMarc - he received two "identical" HP 410C VTVMs. While he tried to get both into a working state again, he mentioned that one of them was too far gone to be continued that time: it needed too much spare parts and would have to wait for some donor system. I reached out to him about maybe continuing the work on that unit? I did some transformer rewinding before after all! So, obviously, he agreed and after hammering out the details for shipping: here we are! Let's dig in!
In this second part, I clean up the case, go over the circuitry on the PCBs, connect up some wires for the probes and make my own DC probe replacement. But then, the AC probe issue is causing some grief: I wanted to make a replacement, but the nice small RF diode tubes I found are lost in the mail somewhere.
The original video by @CuriousMarc is here: youtube.com/watch?v=OOqh2Wqdi4s
0:00 Intro / Recap
1:45 Meter Glass / Cover Plate
4:05 Potentiometer Check
5:25 Mounting Meter / DC Wires and Clips
7:16 PCB Time: Capacitors Cleanup
8:28 Chopper Assembly: Desolder and Neon Test
9:23 Component Check and Report
10:37 Electrolytic Swap / PCB Cleanup
11:28 Chopper Assembly and Input Cap Mounting
12:50 Calibration PCB / First Power Up / Chopper Adjustment
14:11 Calibration Overview / Tube Shield
15:13 DC Probe: Lathe / Plating
17:00 DC Probe Assembly / Ohms Range
18:05 AC? Whaaaa!
18:53 AC Probe Overview and Function Explained
19:55 Peek inside AC Probe!
21:10 AC Probe Test and Calibartion / Covers
22:27 Overview / Summary / Credits / Outtake
Music:
My Train's A Comin'
Unicorn Heads
(YouTube Audio Library)
You can support me on Ko-Fi: ko-fi.com/atkelar
and also on Patreon: patreon.com/Atkelar
Or, you can also drop a virtual coin into the YouTube hat by using the "Super Thanks" feature!
Thanks to everybody who signed up already!
About two months ago, I was watching a restoration video by @CuriousMarc - he received two "identical" HP 410C VTVMs. While he tried to get both into a working state again, he mentioned that one of them was too far gone to be continued that time: it needed too much spare parts and would have to wait for some donor system. I reached out to him about maybe continuing the work on that unit? I did some transformer rewinding before after all! So, obviously, he agreed and after hammering out the details for shipping: here we are! Let's dig in!
In this second part, I clean up the case, go over the circuitry on the PCBs, connect up some wires for the probes and make my own DC probe replacement. But then, the AC probe issue is causing some grief: I wanted to make a replacement, but the nice small RF diode tubes I found are lost in the mail somewhere.
The original video by @CuriousMarc is here: youtube.com/watch?v=OOqh2Wqdi4s
0:00 Intro / Recap
1:45 Meter Glass / Cover Plate
4:05 Potentiometer Check
5:25 Mounting Meter / DC Wires and Clips
7:16 PCB Time: Capacitors Cleanup
8:28 Chopper Assembly: Desolder and Neon Test
9:23 Component Check and Report
10:37 Electrolytic Swap / PCB Cleanup
11:28 Chopper Assembly and Input Cap Mounting
12:50 Calibration PCB / First Power Up / Chopper Adjustment
14:11 Calibration Overview / Tube Shield
15:13 DC Probe: Lathe / Plating
17:00 DC Probe Assembly / Ohms Range
18:05 AC? Whaaaa!
18:53 AC Probe Overview and Function Explained
19:55 Peek inside AC Probe!
21:10 AC Probe Test and Calibartion / Covers
22:27 Overview / Summary / Credits / Outtake
Music:
My Train's A Comin'
Unicorn Heads
(YouTube Audio Library)
You can support me on Ko-Fi: ko-fi.com/atkelar
and also on Patreon: patreon.com/Atkelar
Or, you can also drop a virtual coin into the YouTube hat by using the "Super Thanks" feature!
Thanks to everybody who signed up already!
