[TechAssist] Philips TV TS3260-C121, dead [FIXED]

From: Gary McCartney <number63@xxxxxxxxxxxxx>
To: techassist@xxxxxxxxxxxxx
Date: Thu, 03 Jan 2002 10:23:35 -0500
Could not have found it without the help from my list friends, with
special mention to Jim Myers, Al Leatherman, and Troy Marcy.

Problem was a broken trace between IC7250 pin 40 hor. drive out, and
R3432 which goes to base of hor. driver transistor.  When I was working
on it, the power supply outputs were not quite right. The 8V supply was
measuring only 6.5V. I thought that was just because there was no load
on the power supply so I connected a 100W light bulb across the 129V B+
output of the supply. This brought the 8V output up to proper 8V level.
Then the 3.58 Mhz crystal at jungle IC IC7250 would oscillate for a few
seconds, and also there was a square wave output coming from pin 40 for
a few seconds.
>From that point it didn't take long to figure where the pulse stopped.

Thanks again for everyone's help.


Gary McCartney

McCartney Electronics
7134 Fife Rd, RR 7
Guelph Ontario Canada N1H 6J4
Fax: (519)821-1530
email: number63@xxxxxxxxxxxxx







Original message:


This is a brand new tv that was in an accident. There were approx. 10
traces I had to jump because of small cracks in the board. I have gone
over it thoroughly to make sure there are no more cracks and that my
wiring was properly done. (even still, I leave the possibility open)

There are 3 large IC's. The micro, IC7600 has a 12 Mhz crystal which is
oscillating at the correct frequency. When I push the power button, pin
15 of this IC goes LO from 4.8V to 0V. I can't find any other pin which
changes state during the power button process. I do get 4.8V on a number
of pins and 6.5V on a couple. 

The other large chips are IC7833 and IC3217. They have 18 Mhz and 3.58
Mhz crystals respectfully. Neither of these crystals oscillate. I do get
4.8V on a few pins and 6.5V on a few pins for both these IC's.

On the eeprom, I get 4.8V or 0V on the pins. I have swapped the eeprom
from another set same model.

I measure 129V B+ on HOT collector and hor. driver collector. I also get
13.7V on C2577 and 8V on C2561- these are off the SMPS transformer.

There is no hor. oscillator pulse going to base of hor. driver, and nor
is it back at IC3217.

I've gone about as far as I can without a schematic to tell me which
pins on the IC's should have B+, etc. I do have a couple more of these
chassis, but the boards are broken too far to repair, however I can
steal the parts to repair the one I'm working on.

Would anyone have the portion of the schematic I need? Couldn't find a
listing on Sams web site.

Thanks for any help.


Gary McCartney

McCartney Electronics
7134 Fife Rd, RR 7
Guelph Ontario Canada N1H 6J4
Fax: (519)821-1530
email: number63@xxxxxxxxxxxxx
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[TechAssist] Philips TV TS3260-C121, dead [FIXED]

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