Electronics > Repair

HP 6177A repair (fixed)

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m k:

--- Quote from: coppercone2 on August 01, 2024, 10:05:42 pm ---But here is the kicker: when I remove the op-amps, the 18V rail is 12V. When I put them in it goes to 13V!


--- End quote ---

Can't find 'A' version manual nor that 18V rail from 'B' or 'C' versions.

'B' version has 11.8V regulated supply and 'C' has 12.4V.
Both have also less than solid common.

Maybe negative side is pulling common down.

factory:

--- Quote from: m k on November 02, 2024, 01:20:57 pm ---
--- Quote from: coppercone2 on August 01, 2024, 10:05:42 pm ---But here is the kicker: when I remove the op-amps, the 18V rail is 12V. When I put them in it goes to 13V!


--- End quote ---

Can't find 'A' version manual nor that 18V rail from 'B' or 'C' versions.

'B' version has 11.8V regulated supply and 'C' has 12.4V.
Both have also less than solid common.

Maybe negative side is pulling common down.

--- End quote ---

'A' version is from the mid 60s, it's going to be nothing like the B & C, think more Germanium parts and PNP instead of NPN. I couldn't find any free info either.

David

coppercone2:
well don't worry about the A version my memory of the event is shoddy and the remains are in a jar


still not a bad buy for 2x octal opamp sockets, helipot metal cover, wire wound potentiometer and that interesting transformer that I can one day use for something more interesting

I can test transistors using that socket that have warped leads without messing with them too much, i think they will fit easier into those sockets some way.


If I took the time to install a whole bunch of single wire terminals and redid the wiring harness, maybe I would have had a easier time. But its just too much work for little reward


and beware, that one has wires soldered to both the top and the bottom of the PCB. it would not be easy to rewire it with connectors. You would either need to move everything top side, or make extra long wires so you can pull the board out and disconnect it (hardly ideal for the high performance device). and its not like rows of wires, they are sprinkled about in between parts etc. and its not much room on the bottom either.

i would try to modify it if it was part of stranded space ship



Like if your main project is a current source, then ok maybe its acceptable work load to wrangle with that. mine was a means to a few different ends and it was just starting to piss me off how I am hung up on a current source (I could make my own OKish one in a box for less effort then fixing theirs with good enough specs)


also, beware the connectors, all three of mine had cracked connectors, while maybe there was only a few cracked connectors between the 10 other same form factor HP power supplies I have. I think the current sources stayed in active use longer, while the V power supplies got put on a shelf because their modern replacements were way more likely to go into service and replace them.

factory:
Did you keep the case sides & covers, or use them for something else?
It would have been interesting to see some 'before' pictures too, the early stuff doesn't appear much on forums.

Davis

coppercone2:
No they were all in crappy condition, I polish those side rails if its not too much work (takes a few hours on buffing wheel)

I thought the A model was ever present.

But this one is NOT the cool kind of HP chassis because you can't access the PCB from the bottom unless you take it out. The ones everyone knows and loves have access on both sides, making the diecast 'frame' a cool feature that aids in fast repair of stuff that is solder wired. When you put a aluminum plate in the middle it turns it stupid IMO. !

when the bottom of the PCB is exposed, and its suspended in the frame, its awesome to work on it because you flip it over no worries for 90% of the solder joints. But when there is a plate in the middle, and you need to loosen about 10 screws half way to 'wedge' the circuit board out, it turns into a stupid feature that you 'wrangle' with.


So IMO they lost every 'cool' feature of their die cast frame and instead made it into an annoying 'jingler' that feels like you are working with a metal chain of some sort.


Now, if the 6177A was some how equipped with CAPTIVE screws on the frames that have the ability to be locked into place, that would make it better... but when you have that big aluminum sheet in the middle IMO 100% of the utility from the frame goes out the window. Its supposed to provide high access but it does not, and nothing fits or removes without losening basically everything


Also the cool thing about most other HP frames, is that you can work on the unit side ways to access top and bottom of PCB. If its tightened well, so long it can't fall over on  you, its great to work on. But if the plate is there, it loses this capability. With my other supplies, I had it side ways on the circuit board, so I can bob my head left or right to see both sides of PCB and probe, trace, etc, with schematic infront of me. That was a HUGE benefit.


And while the C does have some cable harness, it still does have an annoying card edge connector where you need to losen everything up into the 'jingle' state, and it still has the plate, so you can't work on it side ways or flip it or access bottom of PCB easily.  >:(



When you can put the unit on its side and access both side of PCB it feels like you are in a CAD program with 360 View IRL.

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