On 12/20/2014 3:43 PM, Tom Miller wrote:

"Lee Gleason" wrote in message
...

I have a crusty old TEK 465 I saved from going into the garbage a few
years back. Finally got time to pull it off the shelf and see what's
going on with it.

I was told it was completely dead and not repairable when I salvaged
it - I thought, I'll be the judge of that. Initially it was stone dead
- no trace, no lights, no fan nothing. I found a 1.5 A fuse (F1419)
blown, and when replaced, it would blow again immediately. None of
the panel lights or the fan would come on, and all the power supply
voltages were low.

I found one bad capacitor that was grounding the +15, when it started
smoking (some faults are easier to locate than others). Replaced it
and then found another cap, C1419, that was shorted that was blowing
F1419. Replaced it and now the lights and scale illumination and fan
come on.

When I press the beam finder, I get a large dot flash and then
nothing. Letting off the beam finder and adjusting the controls for a
normal trace, I noticed that the whole screen is sort of illuminated.
If I slow the sweep way down, I see that a dim 3/4 inch wide by whole
screen tall bar goes across the screen, at about the rate you'd expect
on the slow sweep settings - so that looks like the HV and the time
base stuff is more or less working.

I'm guessing I have some sort of vertical amplifier problem. Before
diving back into the schematics, I thought I'd ask, anyone ever seen
this symptom before?

--
Lee K. Gleason N5ZMR
Control-G Consultants

I would recommend going through the adjustments section of the service
manual. That will offer you a chance to find any out-of-spec parts. The
Tek manuals are very complete and include a theory of operation section
that will answer most questions.
Pay attention to the ripple/noise specs on the power supply test points.
The +55 volt rail serves as the main reference for the rest of the
supplies.

Regards

That's a good idea, but concentrate on getting the numbers close by
fixing busted stuff. I'd recommend against randomly tweaking stuff
in an attempt to fix hardware problems.
That assumes that the previous owner exercised similar restraint
when he tried to fix it.