HP 182C Oscilloscope Repair - Part 1: High Voltage Power Supply "Accident"

We begin the restoration of a gorgeous HP 182 oscilloscope, which takes a turn for the worse when an ElectroBOOM event destroys the high voltage power supply. Which is fine, we just have to un-destroy it.

HP 182 Repair Playlist: https://www.youtube.com/playlist?list=PL-_93BVApb58rsjI0icp8-iY0SWT_n8aA

Stuff that supports the channel:
- Support us on Patreon: https://www.patreon.com/curiousmarc
- Amazon links for the tools I use in the lab: https://www.curiousmarc.com/amazon-links
- Channel merch on Fourthwall: https://curiousmarc-shop.fourthwall.com
- Legacy channel merch on Teespring (I don't have everything transferred to Fourthwall yet): https://teespring.com/stores/curiousmarcs-store

"Elevator Music" Credit: Crinoline Dreams by Kevin MacLeod

Our lovely sponsors
- PCBWay: fast turn PCBs, https://www.pcbway.com
- Electro-Rent: https://www.electrorent.com
- Keysight: test instruments: https://www.keysight.com
- Samtec: connectors: https://www.samtec.com
- R&D Microwaves: https://rdmicrowaves.com

Get more technical info on the companion site: https://www.curiousmarc.com
Contact info: https://www.youtube.com/curiousmarc/about

00:00 HP 180 scopes history
01:45 Initial evaluation
03:54 Power supply tantalum caps checkup
05:07 Power supply electrolytic caps checkup
07:46 Connector repair
08:24 Damaged rail repair
09:22 Power supply frame repair
10:55 Power supply adjustment
12:07 High voltage power supply adjustment
13:21 High voltage electroBOOM
14:51 Why did it arc?
16:43 HV supply schematics explanation
19:31 HV control board repair
22:49 Still no HV oscillator
23:10 Changing the HV transistor, new fault appears
24:32 Try again, still no HV oscillator
26:28 Workaround to start oscillation
30:02 Debugging the blocking oscillator starting problem
32:18 Now it starts, but then it blows up!
32:30 Checking open loop operation, seems OK
35:04 My new HV diode must be too good
37:18 My new HV transistor must be too good
38:21 3kV repaired
39:37 18kV still arcs
40:17 HV repaired, but now we have a new fault!
41:38 More repairs needed in the next episode