TNPA4250 Board Repair
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Re: TNPA4250 Board Repair
They are voltages marked on the SC board. If in doubt refer to the service manual.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: TNPA4250 Board Repair
Well I connected the power cable to the SC board and left the data plug disconnected so the tv would stay on.
The VAD tested fine
The VSCN only had 9.3 volts
The VSET tested 321 and is supposed to test 365 +or- 7 volts
I used chassis as ground reference.Last edited by canadaboy25; 07-17-2014, 10:11 PM.canadaboy25
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Re: TNPA4250 Board Repair
Any ideas?canadaboy25
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Re: TNPA4250 Board Repair
If VSCN tests bad with the SU/SD unplugged you probably have a short on the SC board, double check you replaced all shorted FETs.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: TNPA4250 Board Repair
I tried disconnecting the SU and SD boards from The SC board and the VSCN voltage is still only 9 volts.
I tested all of the MOSFET's again and they all tested fine.
All of the tests were done with the data cable unplugged from the SC board so that the TV would stay on.canadaboy25
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Re: TNPA4250 Board Repair
You may require that cable in to get VSCN, it will be briefly available if there is no fault with it so try that.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: TNPA4250 Board Repair
With that cable connected the VSCN voltage jumps to 30 volts and climbs to 35 volts but then the TV shuts off.
The voltage in the manual is much higher than this or does it just need time to climb up?canadaboy25
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Re: TNPA4250 Board Repair
It should be around 140V so that is bad.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: TNPA4250 Board Repair
Well of it's not a a shorted transistor what else could it be?canadaboy25
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Re: TNPA4250 Board Repair
Bad VSCN generator circuit, leaky transistor, bad diode are possibilities.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: TNPA4250 Board Repair
Well I recently picked up an oscilloscope and a desoldering station so those should make troubleshooting go a lot quicker.
I have a lot of time to work on this so if you could tell me anything that I should test I would greatly appreciate the help!canadaboy25
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Re: TNPA4250 Board Repair
What oscilloscope did you get? That would be very helpful.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Comment
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Re: TNPA4250 Board Repair
Nice choice! Very powerful scope!
Connect your oscilloscope to the SC output. If you need help locating where, post a clear picture of it.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: TNPA4250 Board Repair
Would you like a picture of the SC board?canadaboy25
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canadaboy25
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Re: TNPA4250 Board Repair
I found that test point.
Am I supposed to scope that output with the TV turned on? If so should i have the main power connector and the data connector coming from the main board connected? If i have the data cable connected then the TV shuts off in a matter of seconds. Will that be long enough to perform a measurement?canadaboy25
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