On 12/20/2014 5:03 PM, Lee Gleason wrote:

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?

Re-capping the whole thing would be a good start, I expect. I have a
475 that I'll have to do that to one of these days.


Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net