HP 410C VTVM (as seen with

HP 410C VTVM - Workshop Project #29

About a month ago, I was watching a restoration video by ‪@CuriousMarc‬he 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!

The original video by CuriousMarc is here:    • HP 410C Vacuum Tube Voltmeter Restoration  

0:00 Intro / Unpacking
1:30 Overview / Disassembly / Power Switch Diagnosis
3:20 Power Switch Restoration
6:50 Rear Panel / Transformer / 7 Ohm Resistor Located!
7:50 Electrolytics
9:18 Transformer Diagnosis / Plannning
12:50 Transformer Unwind
14:10 Transformer Winding
15:40 Laminates / Validation
16:30 Case Cleaning / AC Probe Socket Clean
17:50 Waver Switch Cleaning
20:15 Power Socket Mod / Assembly Start!
21:45 7 Ohm Resistor Fix / Assembly
23:10 Unbending and Mounting Front Panel / Grounding (COM) Wire / Back Panel
24:20 Power Supply PCB / Spade Connectors
25:42 Power On! / AC Issue
27:45 Overview Part 2 / Credits / Box?!


Music:
My Train's A Comin'
Unicorn Heads
(YouTube Audio Library)


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