--- In TekScopes@..., "Petrosilius Zwackelmann"
<michael.petereit@...> wrote:
Well, all tubes below the CRT are working. I didn't checked the CRT
so far but try what you suggested.
Btw: The startup behaviour of the scope is strange. On the first
start after around 1 minute a relais was working i the back, below the
big fan. After another 30 sec the relais release with a big spark.
I don't think it should release until you switch off the power. This
must be the relay which switches on the anode voltages after the tubes
are at working temperature.
BTW does somebody know how many different thermal delay tubes there are?
Now the startup is different. The relais is working after 30 seconds
but do not relase the contact any more. I assume some capacitors might
be charged to high and keep voltage.
I'll try agai once I'm back home tonight.
BR,
Michael
-------- Original-Nachricht --------
Datum: Mon, 05 Feb 2007 02:35:04 -0000
Von: "m38a1_1962" <m38a1_1962@...>
An: TekScopes@...
CC:
Betreff: [TekScopes] Re: old fashioned 535 - first start after 35 years
Before you go too far with the chassis cleaning and wholesale tube
testing, check and repair the low voltage power supplies first (be
especially wary of the bypass capacitors across the precision voltage
divider resistors). If the voltages are all in tolerance, look at the
high voltage rectifier tubes under the top HV cover to see if their
filaments are glowing. This will tell you if the HV oscillator is
working. If they are glowing, the CRT filament should also be glowing.
You won't be able to fix anything else until the power supplies are
working. BAMA has a 535_545 manual listed for free download if you are
in for some troubleshooting. Good luck.
--- In TekScopes@..., Artek Media <manuals@> wrote:
Michael
For starters , do a search in the Tekscopes archives for a a long
email thread on washing and baking old scopes to get the grime
out .
It may be as far back as two years ago but there was a lot of
discussion.
Next I would carefully remove and mark the locations of all the
tubes, find a friend with a tube tester and test all the tubes ...
Once you have a clean dry scope and a good set of tubes time to
start
tracing the circuits for bad electrolytic.. Many will suggest that
you just replace them all :-)
Does the filament on the CRT glow ? If that is dead ...you may
be out
of business till you find a doaner scope
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