[TechAssist] Re: RCA PTK169PGB P52738WK injected problem--I think
- From: "Gemini Computer & TV" <geminitv@xxxxxxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Wed, 22 Jan 2003 13:38:02 -0500
Perhaps this may help:
The *Convergence* was out on both the red and blue horizontal linearity. The
controls for this adjustment had little or no effect.
The output stage was still well balanced with no evidence of output
problems. Checking the input waveforms, the vertical parabola waveform was
too small at U8107 pin 7. The waveform was down in the millivolt range when
it should have been about 1.5Vp-p. The correct input waveform was present up
to R8392 where it then lost nearly all of the vertical switch pulse.
Replacing U8107 repaired the set.
*Horiz poor*. Red and blue *Convergence poor*.
T7001 pins 4 to 5 checked open. After replacement of T7001, the overall
focus was poor. C7080 across T7001 pins 2 and 3 was found to be open.
Replacing T7001 and C7080 repaired the set.
The red signal was out of *Convergence* and could not be adjusted.
R7056 overheated. The emitter voltage at Q7016 and Q7017 were both -6V.
Most DC voltages throughout the circuit were off significantly. Switching
the red and blue yoke connectors did not help. U7002 pins 1 and 2 were +14V
and -1.6V, respectively. Comparing static resistances between the red and
blue circuits, Q7014-B to ground read infinite, whereas Q7026-B read 12K.
R7049 was open. Replacing R7049 repaired the set.
The blue *Convergence* was six inches off of the green.
R7098 was getting hot. Resistor R7091, in the base of Q7026, had changed
value. Replacing R7091 repaired the set.
*Convergence*. The set had no adjustment of right and left vertical lines.
The signal at T7001-4 measured 5Vp-p instead of 8Vp-p. Adjustment of R8226,
R8228, R8230 and R8232 had no effect. Replacing T7001 restored normal
operation.
*Red and Blue* is misconverged from the green horizontally. The red and blue
horizontal linearity controls on the convergence board had no effect.
Determined the problem was on the PTV AUX board by substitution. The
waveform at J7005 pin 4 was a low amplitude sawtooth instead of a parabola.
Found T7001 in the dynamic focus circuit was defective. Replacing T7001
repaired the set.
Red and Blue *Horizontal* linearity/*Convergence* incorrect. Adjustments
have little effect.
On J8104 pin 5, the HPAR2 signal was less than 1Vp-p instead of the normal
8.5Vp-p. T7001 was defective and, although it checked like the new one, it
was discolored. Replacing T7001 repaired the set.
The *Convergence* was out on both the red and blue horizontal linearity. The
controls for this adjustment had little or no effect.
The output stage was still well balanced with no evidence of output
problems. Checking the input waveforms, the vertical parabola waveform was
too small at U8107 pin 7. The waveform was down in the millivolt range when
it should have been about 1.5Vp-p. The correct input waveform was present up
to R8392 where it then lost nearly all of the vertical switch pulse.
Replacing U8107 repaired the set.
Bob Waterman, CET® #RI-28
Master Technician License #9109
Service Manager
Gemini Computer, TV, & Security Alarms
(508)695-7302
(508)695-7769 FAX
geminitv@xxxxxxxxxxxxxxxx
geminitv@xxxxxxx
----- Original Message -----
From: "Lyles Tv" <tech@xxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Wednesday, January 22, 2003 1:09 PM
Subject: [TechAssist] RCA PTK169PGB P52738WK injected problem--I think
> Jeesh--I can blame this one on the telephone--kinda. Set came in
dead--chirps. I replaced all the normal (for me) parts in the PS and HOT
circuit. Set fired up fine and played for2 days while I waited for the HV
splitter to arrive, as I allways replace these on virgin sets to eliminate
repeats. While replacing it, I pulled off the red crt module to give me
more room to work with---big mistake---between the time I started to replace
the splitter, and finished reinstalling it, I had 3 phone calls. Of course
this eliminated my "Don't forget the crt module" post it note I put in my
mind----gone. I fired it up with the module off and the first thing I
notice is that is out of convrgence (horizontal) and in the next instant
realize that there is no red. I immediatly assume I had crushed the red
anode lead in the splitter (even though this is an original replacement and
normally this don't happen with those) I pull the red anode to see no
problem, and only then notice the
> red crt module laying there. Reassemble all and still have no horizontal
convergence. red and blue move, but are to far out to be pulled in. I
have 11VDC going into pins of the 3 amp IC's on the convergence board
(U8201, 202, 203) but nothing coming out. Before I pull the schematics--I
am fishing for a common problem first.
> TIA
> Jeff
> Lyles TV and Appliance
> 17 S Washington St
> Elkhorn, Wi. 53121
> ph 262-723-3477
> fax 262-723-3658
> tech@xxxxxxxxxxx
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