"Ancient_Hacker" wrote in
ups.com:


John Hudak wrote:
Hi:
I recently acquired a Tek 475 in what seems to be fairly good shape for
its age. It does have some minor problems that I'd like to take care of
and I am wondering if there is a website/discussion forum that could
address some of the following (or if somebody would want to respond
here, that would be great too!):

1. Noisey controls and switches - I plan on carefully cleaning with
contact cleaner (isopropel-based, no lubricant), lube shafts where
necessary.

The pots are all the sealed type. You can clean them by either turning
them back and forth FIFTY-SEVEN times, or if the pot has four little
screws on the back, loosen the screws a few turns ansd then pry open
the case so you can squirt in some cleaner.

I've handdrilled tiny holes and used a syringe or glued a needle to the
cleaner tube.

One handy little trick is to wind a couple of turns of insulated wire
around the knob and move the wire back and forth,rotating the shaft
rapidly.


2. 2 MHZ wave forms are out of focus when the 100 MHZ and 200 MHZ bands
are selected, it is sharp in the 20 MHZ BW. - Suggestions?

That's your local Tv stations muscling into the circuitry. It should
go away if you put all the covers back on and use a good coax cable
between the signal generator and the scope.

3. Some floating of waveform when observing a trace for a period of time
- e.g. 2-3 mins.

Put the scope on a variac and turn the voltage up and down. There's
likely a weak or poorly regulating power supply. The power supply
capacitors are often marginal and need replacing.



They can also LEAK electrolyte on the motherboard and eat thru the
traces,or short out things.


--
Jim Yanik
jyanik
at
kua.net