HP 6177C DC Current Source Repair and Restoration (COMPLETE)

[coppercone2]

and after removing the main PCB to clean it off after replacing everything, I noticed it was super stressed by the screws and made a nasty sound when I loosened it (I did the repairs in chassis using solder extractor and carefulness). (I did test it before the removal, it was fine, just very dirty)

When I replaced it, it stopped working. same problem as the other one. I cut out the cable harnesses to make sure their fine (upon giving up) and they are fine.

This one was very cheap but I give up on this series, I still don't like how its built, you still can't just remove the boards

the hell with it 

I like the harrison HP voltage sources (I have like 10, they all survived all sorts of maitence abuse), the current source can suck a egg. this peice of shit is giving me anxiety, and I know whats going to happen when I trust it on a expensive laser diode like I was planning on.


the cracking noise is similar to what I heard when I desoldered a VFD on a sony stereo. It had like massive PCB strain. I see the board was either warped or just poorly drilled (that is, the assembler loosely put the studs and shit together, then tightened them all up, because during reassembly I noticed one of the studs was at least 3mm off, because I tightened them to the backer plate before adding the PCB), so more then likely the board was 'stretched' for a good 40 years and then I let it go and something happened. I am not investigating what happened because I am sick of this model series and I don't want to look at the schematics again o probe it

[motocoder]

I think it's more likely that the chassis was warped. A piece of equipment this old, purchased used, has a high likelihood of having physical damage.

Regardless, these units are not poorly made, nor poorly designed, and quite a few people have them and like them. I think most, possibly all of the test equipment HP was making during this era was topnotch.

I put a lot of time and effort into this post, so I would really appreciate it if the last post in the thread isn't you threadcrapping.i humbly request you be considerate and just move on.

[coppercone2]

im not going to get attached to what is essentially a old gear pump

your mod does work, and my luck is unusually bad (statistically) or there is just some flaw with these things breaking

my suggestion is don't pay out the nose for it, because it was on a analog devices photo, and there is a good chance you will be faced with a very difficult repair

in the interest of taking luck out of the equation and finding a cure for HP rabies, I ordered a third one 

[coppercone2]

you might be right, there is some really evil shit going on with the cable harnesses or the switches. the main cracker looks like it works.

it looks like its some kind of haunting 👻

so it looks like it might just be two metric tons of work