TV Trouble 2

[qdgjcl]

I posted a topic about a year ago about a Zenith TV I was trying to troubleshoot. I had to put it on hold to take care of other things. Now I am ready to fix it. Edd Whatley was helping me and I would like to know if Edd is still available. <p>Thanks, <p>Brad.

[Edd]

Go dog go...in the words of Dr Seuss.
Looking back to your previous post info which seems to still be back in archives: <p>http://206.131.241.58/ubbcgi/ultimatebb ... t=000961&p<p>You should be 90% of the way there with the info already supplied. Your initial snag seemed to have been ID of the tuner ....which I gave you lastly... as a convenient place to clip on your meters ground lead for a cold ground reference point.
I stongly think your problem will be found as being thermally crazed/crystallized ring solder joints on the specified vert power output IC or the floating lead(s) of the large mylar capacitor(.22/.47?) mounted just to the IC cases side.<p>
73's de Edd<p>[ March 02, 2004: Message edited by: Edd Whatley ]</p>

[qdgjcl]

Hi Edd there has been a small change since the last post. The original TV is gone, but I was given another Zenith that has the same problem. It’s a later model 1995 (SR2573DT), but I think the inside is the same. I went back through your previous posts and did everything you said. I found the Identifier # on a blue rectangle shaped component I couldn’t figure out what it was, the # is 9-1551. The only difference is the # on the Vert out IC heat sink it’s 126-03440-03. Other than that I think everything else is the same. If so I went through the same checks you said before and everything is ok up to checking the two supply voltages to the vert out stage. I am still stuck on finding out where to reference the cold chassis grnd. The tuner is connected to the back of the TV and is where the coaxial cable is connected to. If this is correct and I need to hook my negative lead to a ground where exactly do I hook the lead is there like a test point on the board near the tuner or do I hook it to the tuner itself? Let me know and thank you for helping me.

[Edd]

Seems like you have successfully found the Zen part # for that vert IC’s sheet metal stamped heat sink.
The Vert IC itself is the small black rectangle at its bottom center apex and its part # prefix will typically start with a 221-….but, its compressive/captive mounting clip will be hiding its symbolization markings.
Seems like the initial query would to be to see if you have fired up the set while observing the collapsed picture and subjected the top of the vert heat sink to the old tap-a-tap-a test and see if there was any degree of partial/intermittent vertical sweep restoration. Next, after a power down, have you tilted the main chassis up an performed a highly illuminated micro inspection of the Vert IC’s soldered terminal joints and its associated ancillary components clustered around it for micro solder joint ring fractures ?
If you haven’t come to a solution by this point, yes, the tuners casing has several adjacent holes in it which to provide a good grip when a micro hook or alligator clip lead is bridged between two close holes. Firstly, look thru those selected holes and be sure that any inwardly clip protrusion would not touch any bare components internally.
Your 9-1551 is the valid identifier for your whole Super-chassis. I will check down in the LRC and see if there is documentation on that unit and I will consult for further info if required.
RSVP<p>ADDENDA:
Looks like the other unit used the same Super-module and that I have already Really-searched out for you on the above post, so refer to it unless you really need more info.<p>
73's de Edd
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<p>[ April 20, 2004: Message edited by: Edd Whatley ]</p>