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No but it seems that these caps are time bombs for this scope series. There are dozens of reports relating damage to to the board de to leaking. I want to act BEFORE the worst happens

One main problem here is that there is no second oscilloscope,? I think. Interleaved: Might be.? It does sound plausible.? That may be found out after the short is replaced He might have replaced

that is correct and those were replaced on sight, usually failure/problems? began 3-10 yrs after mfg....I chased my tail for weeks years ago because of the poor socket issue. mill max sockets seem to

I think they may have thought that the greater pressure was better, but didn't realize that surface area plays a part as well. Or maybe it was cheaper? Harvey

Barry, The scraping is only enough for contact to be made by the pin and socket contact. Unlikely you will see any scratch marks. Do not scratch the gold. The oxidation is more on the socket than the

James, With C1751 being so low in voltage, that makes me think that condenser is open. Even with the output of the regulated being too much, the main B+ at this point will not drop that much. See if

I didn't know that. Was that done to lessen the stress on the pin's bending point? If I recall correctly, the sockets in the HP3456A gripped on the flat sides. Thanks, Barry - N4BUQ

Is the bridge connected to the transformer? What AC voltage do you measure at the bridge input? Do you see high ripple across C1751? This needs (C1751 not measuring 20+V) should be fixed

More good news. The elusive short is on the A4 Vertical Output board. So, I 'hadn't' isolated all of the boards... This is indeed educational! Nothing like teamwork to crack a problem Kinda like

Happens to the best of us....... <grin> You may not have. Then that says that 1) you need to just disconnect the boards. 2) whatever you couldn't disconnect, and you've checked C1757 and CR1757

If I remember properly, one thing that distinguished the Texas Instruments sockets was that the IC pin was gripped by the small edges, not by the larger flat surfaces. Harvey

Hi Harvey, finally a green light to remove parts. I thought you'd never ask... : ) If I am honest, I am not 110% sure that I have isolated all the boards. Obviously the A10 is directly

H?kan, Thanks for that link. I was pretty sure the ones on that board are not Texas Instrument sockets. I think HP has had their share of bad sockets and I think those might be TI sockets. Those

Mark, I may do that. I've just had too many weird problems with it and I'm doubting this will be last I see of it. I don't think, though, that I'll do any scraping. The custom ICs have gold-plated

Disconnect everything but the main power supply.? All the cards and mainframe ought to be disconnected.? That means if there's a short, it's on the power supply board. Think of it as the ultimate

Interleaved: A diode tester will not tell you much about a zener diode except that the diode is open, or shorted.? Zener diodes when forward biased

James, Forgive me if I give redundant information. You may have to replace more tantalums on the 15V line. See about the fan board. That could cause the loading. Unplug it to see if there is a wanted

Today has been a loooong day for me, but tomorrow I intend to go through the entire +15v rail to test, measure and record each component, across itself and relevant to ground. There is clearly a not

VR1724 hasn't been replaced by me (yet), and tests at around 0.6v forward and '0L' in reverse, on three different testers with the unit off, and reads around 0.270v with the scope switched on.

The really bad TI sockets are easily identified by the profile at the short end. Check here https://w140.com/tekwiki/wiki/Bad_TI_IC_sockets Disregard the text above "DIP sockets are ..." and the