PSU for test

[bruce0]

Most units probably never got "gunked" in the first place.  I think you are right someone must have put something in it

Still if the switch is a "little one" (dpdt) you could try a replacement or even replace it with a little toggle and wire it to the board.

 

[Jidis]

Bruce- Good news. Got it!

It was one of those little 'V' shaped springy contact things that short the pins together. I had to smash one yesterday when I first tried to reassemble a switch and had it installed inside-out. When I bent it back to form, evidently I made the contact side just the slightest bit too short. Now it's the right shape, and all 60 pins are doing their thing. Wish I had figured it out sooner and hadn't put so much wear and tear on everything, but it'll probably be fine.

Next, I'll be jumping pins on the top of the switches and finding alternate connection points for jumper wires since my pads and traces probably aren't to be trusted anymore, but that's a fairly straightforward job.

Much thanks to all for the help!

 

[Jidis]

It's alive and well. 

I held off on posting a success report last night as channel two had some weird issues with the 1x/.1x switch. Turns out I had glanced over my pictures too quickly and convinced myself that the switch/PCB connections were identical on the two channels (which they weren't). Had to remove and move a few of my switch jumpers, now it's fine.

Things would have been much easier had I not botched the board up so badly, but the more I think about it, the more I think it probably wasn't possible to cleanly remove all of those switches given the age and condition, without having to touch up or jump anything. I'll definitely be more careful next time though.

And again, a zillion thanks for the help!

George 

 

[bruce0]

Well it looks good, and the price is right.  It included a free lesson too!

I love my HP supplies, the analog world with knobs and meters is so much nicer than my programmable fluke PSU with it's lighted LCD display.  Sure voltage is not to 10ths of volts unless you adjust with a DVM, but who cares for our purposes.

I got this programmable FLUKE DVM a couple of years ago (http://www.ebay.com/itm/Fluke-PM2812-Dual-Output-Power-Supply-/160575398194?ssPageName=ADME:X:AAQ:US:1123).  I bought it because I could see from the picture that they had removed the sense strap on the back.  I cleaned off the marker, and put on a strap and poof ... no more fail.

I much prefer my HP supplies, and end up using the FLuke like a glorified wall wart (it is easy to turn on and off).

 

[Jidis]

Man, I didn't think eBay would show you an auction from that long ago now. Awesome deal on that Fluke. All the auctions I see look like it's in the 5 or 6 hundred dollar range used.

It's weird how prices are all over the map for this stuff. My 6205 has tons of buy-it-nows for $200 and up, but then if you're patient, they're frequently going for $50 (or less). Agilent's tune-up cost is something in the two hundred buck range, and I saw another guy online who had one with a dead transformer just a couple years ago, who had a rewinding service make him a new one for something close to two hundred as well. I don't get it.

By the way, may have spoken too soon on mine. I can't see any meter activity in "current mode" on either side, but I'm in no hurry to dig back into it at this point. I'm fairly confident it isn't my switch/PCB work at least. That stuff was checked multiple times by the end of the whole cleaning ordeal.

I think all my test gear has launched some sort of rebellion recently. My antique Heathkit MM-1 is giving me voltage readings that are all low by a volt or more, and the only other thing I've got to check current is a DVM, which appears to be refusing to pass any for some reason.

Take Care,

George

 

[dfuruta]

By the way, may have spoken too soon on mine. I can't see any meter activity in "current mode" on either side, but I'm in no hurry to dig back into it at this point. I'm fairly confident it isn't my switch/PCB work at least. That stuff was checked multiple times by the end of the whole cleaning ordeal.

Did you test this under load?  Won't get much current if it's open

 

[Jidis]

dfuruta,

Yes unfortunately, with several different loads. Also tried the .1x switch to jack up the meter reading.

George

 

[dfuruta]

Still, a nice little box!  I'm impressed you managed to get those switches cleaned up.  Not sure I'd have the dexterity or patience.

 

[Jidis]

Well the cleaning of the switches was nothing compared to the job of undoing my slaughter of the PCB. I now think I could have done much better with the desoldering, but it still would have been a mess. It's one of those old light green translucent boards, and like I said earlier, the pads almost dropped off the board with the first touch, plus there were so may pins and the fit was so tight, that just one little speck of remaining solder would hold the whole switch in place, so I kept having to go back and reheat different ones. Gave me a lot of respect for you guys who specialize in that sort of thing with all the restoration work. Not easy at all.

George