I've been working 10-14 hr days during the week leaving me very little time in the lab. I'm also trying to locate the proper silver solder for use on the ceramic strips. Out of the half-dozen Teks from this era I've had over the years, not a single one still had the Tek provided solder despite very few repairs if any done on any of them
.
rant: Fleabay is full of 'silver' solder aimed at Audiophools. I contacted a seller that has silver solder for 'high end audio
' that replied to my query of composition that it was a secret formula
. /rant
Until I can locate credible silver solder, I can't easily pull components which is why I just pulled a few of the tubular brown caps to check for leakage.
Might be the transformer...
That is also mentioned in the SM. Unfortunately, Tek didn't provide nominal resistance figures for it. Visually inspecting it, I don't see any signs of distress and it's not getting appreciably warm in operation. The fact that I get some HV before it decays and it looked fine, I initially discounted that as the issue.
Might also be leaky caps in the HV side...
It's a big ceramic cap which I only tested with the LCR meter. My old Heathkit Cap checker only goes up to 450v for leakage tests. I do have a 6KV/10ma power supply I can use to check it but need to source the correct solder first.
Thanks for the ARF link. I did a bit a sniffing over there via Google but oddly that post didn't appear in the top few results.
It's hard to understand why in 2016 people still aren't clued in about this...
In the words of Zeppelin: Nobody's fault but mine.
John Q. Public isn't very bright (spending too much worrying about the Kardashian's -whoever the heck they are). I do know better and should have offered them an extra 20 bucks to pull each tube and wrap it in newspaper with a piece of paper identifying its location. It's always best to double box gear but due to it's size that probably would have meant freight.
what is the voltage drop across R812, the 27k...
I have to clear the bench to get my 3D printer set up to print out some prototype parts for a product I'm developing (not electronics related), as well as a bushing for the rear of the CRT on the 575 which was brittle and basically disintegrated in shipping. I won't get this back on the bench until the weekend when I can check that. Since the HV divider chain seemed to be functional (all related controls did 'stuff') and the resistors all measured up, I had discounted there being an issue there or within the CRT but maybe I shouldn't
.
Under the fault condition, are both the HV rectifier tubes glowing bright?
No, they visually appear to be fine, no signs of arcing or corona. One had been changed so I was a little suspect there could be a problem there. I had a Tek 551 Dual Beam scope with a lot of HV issues some of which were caused by a bad rectifier. I picked up 2 on Fleabay for $5 shipped just in case (thank goodness no Hi-Fi sets used these or they'd be an order of magnitude more expensive). I've got a pair of x100 scope probes I bought for use at work (I repair CNC machining centers) that I'll try to remember to bring home this weekend to check them.
This is my first post. I know it's customary or by protocol to first post in the introduction thread but I thought I'd jump right in and post a reply to this thread.
In honor of Dave - No Worries! Ultimately, this forum is all about helping people, not talking about ourselves. Great 1st post. Nothing is as valuable as direct experience.
I picked up a Tek 575 at a hamfest about a year ago. It had the same problem with the HV collapsing after a few minutes of operation... I replaced C809 with a ceramic capacitor of the same value with a 3kV voltage rating.
Excellent, like yourself, that would have been the last one I'd of pulled due to it's problematic location. As you experienced a similar fault, there's a high probability that is going to end up being my problem as well. In the thread on ARF, a member posted a cap list I think with DigiKey part #'s. It's pretty evident that I should just recap the whole HV section.
Thanks to everybody who's replied. I apologize for the long reply. I've been attempting to reply since Monday but life keeps getting in the way.