Chris said:
Huh, can you be generously more specific?
Chris Lusardi
No - and it's not a question of generosity. The service manual
is very specific. The Ebay entry said the sale to you included
the Tektronix 475 service manual. I cannot do a better job than
they have done in the manual. The first step in diagnosis, per
the manual, is checking the voltages. The manual tells you how
to set the controls on the scope for each voltage you need to
check, which voltage to check first, second, third, etc., what
the voltage measurements should be, where the test points are
and so forth. In short, it tells you everything a technician
needs to know to check the voltages. It does assume that you
know how to use test equipment without destroying either
yourself or the test equipment or tthe 'scope you are servicing.
You probably have a DMM, which will be suitable for most of
the checks. If you don't have one, buy one. Even a cheap (<$50)
DMM will be fine to find a supply out of whack enough to cause
the problem you have. You will need a high voltage probe to check
the high voltage, if all the other voltages check out ok. As I
recall, the high voltage was the last, or close to the last,
voltage check to make, so you may find a bad supply before you get
to that. If so, fixing the bad supply may restore proper operation,
and you won't need to go any further.
If you do end up with a failure in the HV section, do not attempt
to repair it using any old solder. Tek used special solder on the
ceramic strip contacts that some of the high voltage parts get
soldered to. They included a small amount of solder for repair
purposes on the inside of the back cover. It is needed only for
connections to the contacts on the ceramic strips - regular rosin
core solder can be used elsewhere.
Ed
