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(and hello all, I'm a new member)
I also have a 531A I wish to repair but I am fortunate enough ot have the manual.
I recently found scans of the schematics here http://ibis.telesat.si/tek/tek531A.htm
I don't know about the 535 but the parts numbers have changed between 531 and 531A so it's not that easy to locate the actual parts if you don't have the exact schematics
--- In TekScopes@yahoogroups.com, "e_eng_ed" <edsparkie@...> wrote:
Steve, This is great info! It really gives me a head start. I picked this up a few weeks ago. It worked briefly then the trace died. I was planning on cleaning the whole thing anyway. Hopefully with your info I can get it working.
--- In TekScopes@yahoogroups.com, "Steve" <ditter2@> wrote:
--- In TekScopes@yahoogroups.com, "e_eng_ed" <edsparkie@> wrote:
Does anyone know if there is a free download of the 531a operation and service manual. I found the 531 on BAMA but would like to find the 531a.
I had the same problem looking for information to repair a 541A. In my case, I have a manual – 531A/541A that is supposed to cover both models. However it lacks all service information for the 541A.
You can get all the information you need by using a 535A manual which is available on the BAMA site. The only difference is the additional B time base. So if you ignore three pages of schematics – the B trigger, B Time Base and B Time Base Timing Switch, the schematics are almost identical.
There only difference is some additional options in the wiring of the Horizontal Display switch, and the added Delay Pick-Off circuitry. Compare this with the 531 manual you have already downloaded, as this part of the circuit is identical between the A and non-A models.
For that matter, you will find the majority of the circuits have not changed between the original 531 and the 531A. The only major change between the 531 and 531A (as well as the 541 and 541A) is the timing switch. The original scope used two switches to set the time base. One set the time/div range in decades (by powers of 10^3), while the second was a multiplier. This is a holdover from the original Tek non-plug-in scopes. Obviously this arrangement is a pain for the user, as most people simply turn the knob until they get the correct number of cycles or time resolution they want to see on the screen, then look at the knob to see what the time/div is.
Some of the tube types may have been updated in the A model, but the circuit wiring is identical. The original 531 used selenium plate rectifiers which were changed to silicon diodes during its production run. The 531A started out with silicon diodes. Early 531 manuals will not show the silicon version, which requires additional resistors in series to account for the higher resistive loss of the selenium rectifiers. But the power supplies in the 531A and 535A are identical, so again a 535A manual will cover your needs.