[TechAssist] Re: 2nd request. PTK169PAAS..Shutsdown.
- From: "Larry E." <videotech@xxxxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Mon, 08 Mar 2004 14:06:58 -0500
Jeff, first thing you need to do is CHANGE CR4118, don`t test it because they
are
notorious for failing under load (such as startup) also check cr4118`s filter
C4145.
The designation; <72-A> is the grid designation on the paper schematic, Reg B+
in standby at CR4116`s cathode should be 143-160 in run it should be approx.
143 volts. You didn`t mention which caps so I`ll mention the most notorious,
C4102
the 2.2uf @ 100v,(just replace it) Do you have 12-13 volts on the collector of
the horiz. drive transistor
in standby mode? Have you pulled the anode lead from the splitter to see if the
set stays
up with audio? Did you check to see if it`s wet around Y4301 & C3810 ? that
cap will leak
and destroy the crystal which is for horiz. drive, the board will look wet and
if you unsolder
the crystal it will smell fishy. Part # for crystal is 200210, it`s located at
the right end of the
big chip and it`s blue.Is your 5 volt line running in standby ? Do you have
clock and data
5 volt line(s) ? 5 volts on pin 1 of U3101? If not CR3101 is probably shorted
or not zenering
at 5.6 volts, C4108 will also cause standby B+ too be too high, There are soooo
many things
that can kill that set, check the above and reply again, remember, change
CR4118 every
single time you work on a 169, I hope this helps you out, Larry E
Larry Eastman
American TV & Electronics
Crystal River, Fl. 34428
Intrepid Video Support wrote:
> Still working on this, can not figure out why it is shutting down as HV
> builds.
> Would a defective vertical section cause this set to shut down?
> REG B+ is 170 in standby, drops to 162 when I press power..is this normal on
> this set?
> Schematic shows Reg B+ <72-A>, Not sure what that means.
> I've repaired many of these with a splitter, flyback or replacing the parts
> in the power supply.
> I've done all this and set still shuts. I've replaced all the caps, the boxed
> caps in front of the HOT,
> CR4118(tested OK), U4101, Q4101, Q4401..and all the caps. Checked all the
> diodes and resistors and can
> find no problems.
> I'm running out of time on this one....Does anyone have any idea what I may
> have missed?
> Thank you.
>
> Jeff Dougherty
> Intrepid Video TV/VCR
> 263 S Front St
> Steelton PA 17113
> fax...717-564-4952
> www.intrepid-video.com www.tech-repair.net
>
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