Ron.M
Veteran
Feb 10, 2012, 8:41 PM
Post #9 of 17
(2534 views)
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pocketwatch62;.... Could the STK730-130 keep the boards from having any output voltages? YES !!!! & More than likely the cause... Common problem... But , first , lets make sure....OK ??? Second, I have no volts on P/J19701. UNLESS you are reading the volts wrong , That's why you have the convergence problem.... Turn the TV on & please check the voltages on U19700 (STK730-130)... These voltages must be read from "Hot" ground... PLEASE use care so you do NOT short pins together with your meter probe... Can be hazardous to your health OR the TVs...... Hook your negative meter probe to the minus side of C19702... That is a large 220 mfd lytic @ 200 vdc coming off the 4 diodes from the AC line... Use care when connecting your meter there as when the set is plugged in you can get a dandy shock & meet all your dead friends & relatives....... Turn the TV on & please check the following voltages on U19700 (STK730-130)... Pin #1=-40 vdc Pin #2=-33.2 vdc Pin #3=0.0 vdc (Hot ground)... Pin #4=+1.6 vdc Pin #5=+1.6 vdc Pin #6=+1.4 vdc Pin #7=+.03 vdc ( For all practical purposes 0.0 vdc) Pin #8=+.08 vdc (^^) Pin #9=+.08 vdc (^^) Pin #10=No connection Pin #11=+157 vdc Pin #12=+157 vdc Please note that those are approximate & your voltages may vary slightly ...... Then look for connector J19105.... It will be in a cluster of 7 connectors near a corner of the convergence output board... Near J19105 should be a diode CR19200... One end comes from the flyback , the other end supplies 22 vdc to turn on the power supply... Connect the negative probe of your meter to chassis ground (The coax connector on the tuner is ideal) & the positive probe of your meter to the band end of the diode... You should get ~+22 vdc... Post results..... Strange thing is that the heatsink gets warm , (But not hot) on both boards. Could be bad ICs...Not saying they are... Just don't think the same problem with both boards, but possible. You have a missing voltage & we have to find out where it's at... PLEASE post your results.....THANKS....... Have fun........ Later...Ron.M....... Veteran & Retired TV technician
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