[TechAssist] PTK195 Convergence power supplies, switch modes in general

  • From: Wayne Vanaman <Wayne@xxxxxxxxxxxxxxxxxxxxx>
  • To: techassist@xxxxxxxxxxxxx
  • Date: Wed, 09 Nov 2005 15:24:42 -0600

Repairing PTK195 convergence power supply boards that use discreet 
semiconductors, pn 250686.

This basic power supply, with variations, is used in many of the RCA 
chassis, not just this aux power supply board.  Even though the discreet 
component version of this board has only one part number of which I am 
aware, there are multiple version of that part number, some have more or 
  fewer active semiconductors.  There are versions with and without 
input chokes.

There are two things you can do:
1. Troubleshoot to exact parts.
2. Shotgun.

The way I do it is to replace all active (transistors and ICs) 
components and high failure components in the primary.
Replace the opto that connects the primary and secondary.
Replace the active component(s) in the secondary closest to the opto, 
input and output.
Check all pumpup capacitors.
Check diodes.

You need to determine if any of the active components are damaged.  If 
any active components are damaged, replace ALL of them as a set.
Second, determine if there are bad passives-capacitors, resistors, and 
diodes.

If the main power switch transistor is shorted the resistors around it 
are suspect.  On a power source transistor, such as Q19701 or a 
horizontal output transistor which has an emitter or source resistor, 
replace that resistor.

Specifically, on this power supply:

Q19701 246967
Q19702 147665
Q19703 232218
Q19704 229220
U19701 223653
U19700 231525
Q19705 215496
Q19710 216434 (if installed)
R19703 (if damaged)
R19706 250661

In the case of this particular  power supply that is working, but 
producing low voltage the feedback path may be the only damage.  In this 
specific case:
CR19715 feeding the base of Q19711, and CR19706.

Parts list:

STOCK #,
DESCRIPTION,
DRAWING #,
SAFETY CRITICAL

CIRCUIT 250686 CIRCUIT, POWER SUPPLY 15642410 Y
C19700 227069 CAPCD 680PF J SL 2KV 1506510000 Y
C19701 176665 CAP LYTC 220UF M 200V 1517092000 N
C19702 214747 CAP POLY .033UF J 400V 4043458000 Y
C19703 214066 CAP POLY 1500PF K 100V 3093557000 N
C19704 248625 CAP POLY .39UF K 63V 9056827000 N
C19705 214015 CAP POLY 1UF J 63V 9056828000 N
C19706 239176 CAPCC 820PF J NPO 50V 1507089000 N
C19708 146179 CAPCD 470PF K Z5P 250V 3093737000 N
C19709 162787 CAP LYTC 22UF M 50V 7042797000 N
C19710 239130 CAP LYTC 680UF M 63V 7043466000 N
C19711 246952 CAP LYTC 680UF M 35V 1541310000 N
C19712 246952 CAP LYTC 680UF M 35V 1541310000 N
C19713 239130 CAP LYTC 680UF M 63V 7043466000 N
C19714 146179 CAPCD 470PF K Z5P 250V 3093737000 N
C19715 146179 CAPCD 470PF K Z5P 250V 3093737000 N
C19716 146179 CAPCD 470PF K Z5P 250V 3093737000 N
C19717 146179 CAPCD 470PF K Z5P 250V 3093737000 N
C19718 224271 CAP POLY .22UF K 63V 7042765000 N
C19719 220998 CAP LYTC 1UF M 100V 1106709000 N
C19720 156239 CAP LYTC 10UF M 63V 30935880 N
C19721 190538 CAPCD 680PF M Z5P 1KV 11057250 Y
C19722 190538 CAPCD 680PF M Z5P 1KV 11057250 Y
C19723 190538 CAPCD 680PF M Z5P 1KV 11057250 Y
C19724 190538 CAPCD 680PF M Z5P 1KV 11057250 Y
C19725 102230 CAPCD 470PF K Z5P 500V 1529623000 N
C19726 225541 CAPCC 220PF J NPO 50V 3093873000 N
CLIP 181032 CLIP, TRANSISTOR 15089440 N
CR19701 198589 DIODE 70436540 N
CR19702 234048 DIODE 1504770000 N
CR19703 232545 DIODE ZENER 8.2V .5W 1107366000 N
CR19704 198589 DIODE 70436540 N
CR19706 235831 DIODE ZENER 12V .5W 3094868000 N
CR19710 234048 DIODE 1506410000 N
CR19711 220465 DIODE 1504123000 N
CR19712 220465 DIODE 1504123000 N
CR19713 234048 DIODE 1506410000 N
CR19714 226456 DIODE ZENER 10V .5W 9057802000 N
CR19715 239133 DIODE, ZENER 20V .5W 3094881000 N
CR19717 147015 DIODE 1107079000 N
CR19718 147015 DIODE 1107079000 N
CR19719 147015 DIODE 1107079000 N
CR19720 147015 DIODE 1107079000 N
CR19721 140971 DIODE 7043653000 N
FB19700 237504 BEAD 1509165000 N
FB19701 237504 BEAD 1509165000 N
FB19702 237504 BEAD 1509165000 N
FB19703 237504 BEAD 1509165000 N
FB19704 237504 BEAD 1509165000 N
FB19705 237504 BEAD 1509165000 N
FB19707 237504 BEAD 1509165000 N
FB19708 237504 BEAD 1509165000 N
FB19709 161237 BEAD 6045260000 N
HEATSINK 240243 HEATSINK 15171310 N
INSULATO 214613 INSULATOR 15088690 N
J19701 239135 CONNECTOR 6 PIN 15175020 Y
JC19700 181161 RES CMF 1/8W 0% 0R 5088553000 N
JW19700 NONSTK WIRE JUMPER 1508850000 N
JW19701 NONSTK WIRE JUMPER 1508850000 N
JW19702 NONSTK WIRE JUMPER 1508850000 N
JW19703 NONSTK WIRE JUMPER 1508850000 N
JW19704 NONSTK WIRE JUMPER 1508850000 N
L19701 215504 COIL, 22UH 1003807000 N
L19702 215504 COIL, 22UH 1003807000 N
L19703 215504 COIL, 22UH 1003807000 N
L19704 215504 COIL, 22UH 1003807000 N
Q19701 201152 TRANSISTOR 1090550000 N
Q19702 147665 TRANSISTOR 5088878000 Y
Q19703 232218 TRANSISTOR 1511135000 N
Q19704 229220 TRANSISTOR 1506430000 N
Q19705 215496 TRANSISTOR 30946660 N
Q19706 215496 TRANSISTOR 30946660 N
Q19707 215495 TRANSISTOR 11070770 N
Q19708 215496 TRANSISTOR 30946660 N
Q19709 215496 TRANSISTOR 30946660 N
Q19710 215495 TRANSISTOR 11070770 N
Q19711 215495 TRANSISTOR 11070770 N
R19701 248628 RES CFFP 1/4W 5% 390K 1106537000 N
R19702 242626 RES CFFP 1/2W 5% 100R 9057401000 Y
R19703 241313 RES CFFP 1/2W 5% 15R 3094368000 Y
R19704 241919 RES CFFP 1/2W 2% 150R 8044008000 Y
R19705 243994 RES CF 1/2W 5% 1K 1106580000 Y
R19706 250661 RES WW 2W 5% 1.2 OHM 2047059000 Y
R19707 248629 RES MFFP 1W 5% 56K 3094086000 N
R19708 248630 RES CF 1/2W 5% 200K 3093985000 N
R19709 175045 RES CF 1/4W 5% 330R 6044155000 N
R19711 248631 RES MF 1/4W 1% 243R 7043115000 N
R19712 248633 RES MF 1/4W 1% 348R 1106073000 N
R19713 248634 RES CFFP 1/4W 5% 20R 7043336000 N
R19714 174366 RES CMF 1/8W 5% 18K 8043968000 N
R19715 175317 RES CF 1/4W 5% 10K 3093948000 N
R19716 175308 RES CF 1/4W 5% 1.2K 8043700000 N
R19717 190462 RES CMF 1/8W 2% 1K 4043760000 N
R19718 206261 RES CMF 1/8W 5% 10K 6044371000 N
R19719 206261 RES CMF 1/8W 5% 10K 6044371000 N
R19720 190462 RES CMF 1/8W 2% 1K 4043760000 N
R19721 174361 RES CMF 1/8W 5% 1M 4043757000 N
R19722 175039 RES CF 1/4W 5% 68R 5088294000 N
R19725 190462 RES CMF 1/8W 2% 1K 4043760000 N
R19726 181062 RES CMF 1/8W 5% 51K 1106482000 N
R19727 151602 RES CMF 1/8W 5% 240R 6044370000 N
R19728 215206 RES MF 2W 5% 30K 5088416000 N
R19729 200494 RES CMF 1/8W 5% 47K 9057361000 N
R19732 248634 RES CFFP 1/4W 5% 20R 7043336000 Y
R19733 190462 RES CMF 1/8W 2% 1K 4043760000 N
T19700 190507 TRANSFORMER 2048044000 Y
T19701 250662 TRANSFORMER 15645040 Y
U19700 223653 INTEGRATED CKT 1504569A00 Y
U19701 231525 IC, REFERENCE 1506901000 N


Wayne Vanaman
Omega Electronics
6904 W Fairfield Dr
Pensacola, Fl.  32506-3310

Wayne@xxxxxxxxxxxxxxxxxxxxx
WWW.PensacolaTVRepair.Com

850-456-5995 voice
850-458-6369 fax
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