HP 8557A Spectrum Analyzer w/ 182T Repair - Part 2!

Hey everyone! A lot has happened since I first released part 1 of this series (here:    • HP 8557A Spectrum Analyzer in HP 182T disp...  ) attempting to repair this HP 8557A spectrum analyzer plugin in a 182T mainframe. Auroras, eclipses, you name it! It took me a while to return this project because things got busy with work and I struggled to find the right material to perform this part of the repair: replacing the contacts on the switch assemblies in the front end of this unit. I came across the perfect type of fingerstock (EMI metallic gasket shielding) to make these contacts thanks to a member of one of the group forums I'm in. It's from Tech-Etch and it has part # 75RE. Unfortunately the manufacturer only sells in large quantities but I was able to find a sample being sold on eBay! Also, a company called Laird Tech makes this same exact fingerstock under part # 97-134, but of course, they also only sell in large quantities. Just figured I'd share them here so people can either reach out to the manufacturers for a sample or keep an eye out for them on secondary markets. I get so close to finishing this one, but I am met with another unexpected fault ... this one puts up a good fight. Stick around to find out! P.S. I've never used a spectrum analyzer or repaired one before, so go easy on me! Link to LazyElectron Blog on 8558B repair: https://lazyelectrons.wordpress.com/2... 0:00 - Intro/recap of 182T repairs 5:20 – Overview of faults on the 8557A 8:31 – the extender cable setup 10:19 – troubleshooting tree for no baseline 12:06 – checking VR1 zener on the A12 driver PCB 14:15 – checking Q19 on the A12 driver PCB 16:35 – example curve for the J113 JFET on 576 17:44 – primary fault found… missing switch contacts! 21:55 – repairing the switch contacts, material used and how to attach 32:05 – first power up after contact repair! Still needs work 32:56 – possible short-to-ground on frequency switch 33:16 – post-6th reassembly… going over switching orientation 38:25 – Another fault found… tuning switch doesn’t appear to work 39:12 – Calibrator signal appears on full scale! 42:17 – checking for V+ and V- to the tuning pots 42:40 – checking the base voltage of Q7 on A4 PCB during switching 43:40 – checking the troubleshooting tree for incorrect signal shift 45:26 – correcting orientation of BW RES switch using BW5, BW6, BW7 voltages 47:05 – checking FW and CW voltages for tuning pots 50:00 – replacing the coarse tuning pot – success!!! 52:45 - Outro