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i'm not sure of the best way to post this followup for all previous responders see. so, i'm replying to my original post...

i spent some quality time with the new toy today. i guess it just needed some attention...

i turned it on and found i was getting one spot on the screen rather than a massive glow (i kept it de-focused as it was full intensity.)
i looked around at the tantalums that had one smoking yesterday and noticed a solder bead on one of the three.
i poked it and it fell off...and a trace slowly snapped back. some adjustments and things were sweeping! how the heck does a solder bead on the outside of a tantalum cause this? was there a cold solder i tweaked at the same time?

so since it appeared it was not going to catch fire this time, i let it run and things stayed nice and stable.
i turned it off and tested all of the transistors in the area of the smoking tantalum (this is at rear of sweep logic board btw).
they all appear ok.

man, you people with socketed transistors have it easy. try testing a transistor on a 465M. you have to desolder it...no sockets! (except about four i found that probably should not have been there lol) no sockets is part of the "ruggedized for the military" modification.

so, things are working fine with a few mechanical probs. i found a loose transistor preventing the x1 light on chnl 1, stuck it back in and that prob is fixed.

the horizontal position pot is wonky. lots of play. i've seen this before on the 465M. i guess 35yrs of use takes it's toll.

the main intensity pot is dirty or toast. i will probably attack it soon. but careful fiddling and it gets you where you want to be.

the B delay pot knob is offset to 0.2 when bottomed out. and it shows on the trace. i think this was previous owners way of correcting for improper registration on the trace. likely a simple calibration tweak will fix it and i'll rezero that pot knob.

this is a significant one:
the A trig view only shows a flat line but everything is triggering properly (including B sweep stuff).
possibly a loose jumper wire etc. i'll chase it soon.

since it was staying up (for 2 hours now) i took PS readings at test points.

voltage VDC, ripple mV p-p

supply voltage spec ripple spec
+110 108.2 106.7 to 113.3 16 20
+55 54.9 54.62 to 55.39 3 4
+15 15.00 14.75 to 15.26 1 2
+5 5.01 4.92 to 5.09 1 2
-8 -8.01 -7.86 to -8.14 1 2

not too shabby. i may take a look at getting +110 closer to 110. i am still nervous about ps filter caps because my 465M worked for a few hours then tore itself apart with failed caps and exploding transistors. i'll keep an eye on it for a while. it would be nice not to have to recap this thing. (i know about reforming but i'd rather recap and be sure)

all the other bells and whistles seem to be working x10-mag etc. and timing and vertical deflection look right on.

So, not a very exciting fix but so far i have a nice working 465B but i'm quite sure why :-o
phil



--- In TekScopes@..., "pdxareaid" <public_email@> wrote:

I just picked up a 465B off Craigslist. Came with 10x probe.

the ad:
"Unit was working, then stored for 3 or 4 years. When I turned it on recently, it died. There's a beam, but no sweep. It worked well before that. I was hoping someone would want to fix it and put it to good use. Free."


Nice guy...engineer...just did not want to deal with it.
He mentioned electrical burning smell when turning on.

I got it home and spent 10 minutes with it...opened it up and turned it on. Burning smell coming from PS section I think. Whole screen glows off and on, no trace to speak of.
It is in excellent shape otherwise, calibration stickers all over it.

I am thinking PS filter caps to start, then tantalum and electrolytic search after that.
Phil