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Brad, I have had horses for over 40 years and I don't remember going around and smelling warm horse s*hit, have stepped in some and shoveled a lot. Leon Robinson ?K5JLR

So I replaced Q855 with a BD239C and Q860 (it was blown) with a 2N2369 (it is the equivalent of the original 2N5769). But no oscillation in the HV supply. All the LVs seem OK. Any suggestion? By the

?Disclaimers: (a) I own 545, 535A, and 547 but not 545B; and (b) my only 545B manual is the scan from BAMA whose last change is for S/N 2290 and A and B TRIGGER schematic pages drawn by CMD dated 565.

The 466 is a very nice, fast-storing analog storage 'scope. It's well worth restoring. Please make sure that brightness (once you get there) isn't too high. These CRT's are much more sensitive to

The purpose of C1511 is to compensate for the stray capacitance that you have from Q1508B base to ground. This is why a typical value would be for example 10 to 47pF and not 0.1uF. G?ran

Hi Christopher, Fundamentally, I believe it is because there are a lot of other circuits controlled by the many poles of switch 10B (DC, AC, AC LF REJECT, AUTO). Check out Schematic #4 and #5's SW10B

Suggest acquire service manual. Then check all PS rails for correct voltages. Probably PS capacitors need replacing. GL Keith Wayzata, MN

I had an intermittent power switch on my 2465. I seem to remember this manifested roughly as OP describes, e.g. sometimes it would start, and sometimes it wouldn't. Got worse over time. I remember the

I bought this off of Offerup for $20. I wouldn't have even bothered, but the woman had a lot of good dealings, and I don't feel like she had any reason to lie. The scope among other things were her

Hi Jared, I was one of the designers of the AM503A, AM503B, AM5030 and newer TCPA300/400 products. Let me dig through my parts bins to see if I have one (I think I bought some from RAMs way back?) or

Jon, Thanks for confirming that the switch is an unlikely source of issues. Of course the problem now I that I need to wait for another intermittent failure before I can figure out what is wrong. D**n

Being a city dweller, now I know what that smells like... Raymond

The infamous caps on the A5 board are Al, not Ta. Bonne chance! Raymond

hi Guys Am spending the first few days of the newly instigated UK national lockdown calibrating several 500 series scopes – a 545B and a 547. In each case there is an intriguing point where the

Mark I have never seen an intermittent power switch on any,Tektronix scope, but have seen the power connector plastic shaft mechanically come off. I suspect a marginal part in the PSU start-up

John: "when manufacturers changed from wet electrolytics to dry the problems with caps largely ceased" The cap issues are mixed up a bit: a/ Certain types tantalum caps had poor seals especially in

Thanks, I always seem to do better when I know not only *what* I'm doing, but also why.? Considering that we're often repairing rather old PC boards (and yes, I dealt with those things when they were

Nice PCB summary, Harvey!? I've seen what is probably FR-3 in consumer electronics but I've never worked with it.? FR-4 or RF/microwave laminates, yes.? FR-4 is as common as dirt.? ? Jim

I own a 561A and two 564Bs. They were mainstream in the mid 1960s. 10MHz bandwidth and a far sharper trace than you will ever see on a DSO. They all take the same series of two plugins, Vertical and

Harvey White wrote on 1/5/2021 8:55 PM: Hello-- Older imported electronics used a phenolic-based laminate-- typically medium to dark brown and liable to losing its traces when the repairer applied too