Electronics > Repair
HP 6177A repair (fixed)
coppercone2:
where am i?
factory:
--- Quote from: coppercone2 on November 02, 2024, 11:22:40 pm ---someone should 3d model them so you can just get it cnc machined from aircraft aluminum and forget about it
i know people would pay. i probobly would
when I had to fix the one on my RF amp (or was it function generator?) I thought I would pay like 300$ for that part if someone had it :-DD
But I ended up doing a splint with a piece of mild steel and 5 screws.
getting that part is similar stress relief to going through 20 bottles of alcohol
I did find them but I know i will curse myself in a few years if I do sell it because a good current source... might be forever. And it could get adapted to other frame with some work
--- End quote ---
The 2 side panel covers are for a counter, which I imported from the USA, they don't exist in the UK any more, sellers destroy everything for a few glass parts and throw the rest in the trash, before listing them on e$pay, they don't care if it's the last one in the UK. >:(
Also I've not found anything useless that uses that narrow case and can't justify scrapping usable or working TE to take the parts. It's not the only counter I have with missing covers, I've found some of the counters use unique sized top/bottom covers too.
If you want to keep them for something else that isn't a problem, just let me know if you change your mind, doesn't matter if that is years later, I'm quite patient.
The cracked frame I have is also one of the small amplifiers, though mine is the pulse version, very similar looking to the RF amp. Maybe I can straighten & join that one.
--- Quote from: coppercone2 on November 02, 2024, 11:44:28 pm --- where am i?
--- End quote ---
USA, this is not really an issue for me, I have ways to get stuff that ePay sellers don't want to send international.
Re: the wiring one HP current sources, I used to own a late 6186C (300V 100mA), the main PCB was hardwired in that, no connectors for unknown reasons, that one I sold some years ago, which I now regret.
But I solved that by buying a cheap & poor condition 6186B to repair, it's the one with the messy main board, which I posted some pictures of in your transistor tester thread, all those random unmarked transistors & other added parts are now removed.
To make this one even better, they lost the boron nitride transistor insulators & put more heatsinks on the back of the unit, which are live at high voltages. :palm: I don't think they make those insulators anymore, but maybe others in ceramic are available, I've not looked yet.
I noted you asking about the TO-39 heatsinks for your 6177B/C? Seems the 6186C used one, but the 6186B doesn't need one, no idea why.
David
coppercone2:
I finally got around to trying to salvage the rest of the hardware off the remains of the PCB from the scrapped one's PCB (originally I only removed some of the parts for transplanting, aka saved my metal oxide resistors I added), now that I have two working 81's
It turns out those things on the back for the screw terminals (solder down through hole bent plates with hole) were somewhat defective, just like the bus wire that I found that was cracked in half. They are on both sides of the PCB and conform around the plastic bit with the threaded inserts.
I desoldered them and some that I tested basically snapped from a minor amount of deflection, while some of the other ones survived like 4x more bending. It was very brittle.
I was sure that part would be a keeper (it can be used as a solder point for a bolt). :-//
I guess the same thing that caused that copper wire "jumper" arch to crack in half, also effected the screw terminal connectors.
I have seen things like that for soldering to bolts break before, but usually their pathetic sheet metal stampings, these are like pretty beefy, but clearly its not a guarantee to just make it fat
I wonder if its because of thermal cycles, or some kind of corrosion.
factory:
If it's anything like the 6186B, the rear terminal blocks are not supported in any way, other than the solder joints. Not surprized they crack, using a screwdriver will press against them, bending them and repeated use will cause them to fatigue, one has been replaced with a bodge wire in mine (not by me).
I've found some possible alternate solder links to replace the broken ones (made by Cinch), but haven't ordered them yet so can't confirm they will be long enough, the screws are #5 40TPI UNC, there are some Cinch 140 series jumper links I intended to order too.
David
coppercone2:
I thought they were thick enough to not have to worry about that, its at least 3 times as thick as the usual brass hardware
I thought it might be chemical because the nice looking jumper wire cracked too, and its not really doing anything related to threads.
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