Panasonic Viera (plasma) TH-P42S10A (5/2009) - SOS 5 blinks (If i missed any details, just ask)
SC board - TXNSC1EKUU / TNPA4829AD
Description of SOS 5 blinks from Panasonic manual:
"5 Blinks SOS: Pin 60 of the CPU IC9003 monitors the 5V line. During normal operation, pin 60 is kept high. If the 5V line is missing or shorted, a low is provided to pin 60. As a result, the unit shuts down and the power LED blinks 5 times."
TV symptoms at first test:
When powered on there is a relay click followed by a transformer hiss(not buzz or humm, a clear hissss) for approx 3 seconds before the relay clicks again and the unit powers down and begins 5 blink led code (sos-p5v).
No image displayed at any time. No other blink codes, just 5, 5, 5 etc.
P5v measurement at pin 5 or 6 of P25-A25 during brief 3 sec power on period rises to approx 4.59-4.61v before falling back to 0 as unit powers off again. Not stable, never reaches 5v, always gradually rises to approx 4.6 on repeated attempts before unit powers down again.
SS board LED not working. SC board LED not working.
With SC board disconnected from power between P2 - SC2, and also ribbon disconnected between A20 - SC20 - the unit powers on for a slightly longer period (approx 5 secs) and p5v measurement taken during power on period at p25 shows quite stable 4.95v until unit powers off and begins 6 blink led code. The hissing from the transformer on the P board also goes away. Good good - Stable 5v is present between P-A boards, and A board is successfully detecting that the SC board is disconnected. (with SC board re-attached, the unit resumes 5 blink code)
With the SC board disconnected the SS board LED is also now working and switched on. Good. Disconnecting the SC(and SU/SD effictively) seems to have removed the shorting p5v..
With SC board disconnected, measured voltage of tp-vsus (located on SS board just below S11-P11 power connector)using safe insulated clamp type test leads reads same as internal calibration sticker suggests, in my case 209v on sticker, 208-210 measured. ok.
With SC board disconnected, measured TP-VE located on SS board lower right. 140v on sticker and 139.8 measured. ok.
On to the disconnected SC board -
Resistance measurements probed on SC board components in circuit - unplugged from mains and caps carefully discharged via large 5w ceramic resistor before starting:
Q401, Q402, Q421, Q422, Q661 (all TO-220 on heatsinks)& D865(smt, located upper left of board between 2 heatsinks) showing shorted/ continuity in all directions. bad. This is also where i stumbled into other handy threads after googling Q401 shorted tnpa etc - that made finding the rest as easy as following a guide and sure enough, each component mentioned in this thread by the folks who have fixed them was reading dead shorted in all directions.
Have tested and found bad components on SC / y-main mostly identical to the users in this thread, but didn't want to hijack: (*big thankyou's to all here)
https://www.badcaps.net/forum/showthread.php?t=27921
Bad Q401, Q402, Q441, Q442, Q661, D865
I have removed the failed bits from the SC and have the replacement parts ready to go in after waiting some time for delivery, but before i do i wanted to ask for some advice on 2 things in particular:
1/
Before installing the new components on the SC board I would like to test with some degree of certainty that it is otherwise free from other failed bits or shorts etc. Any advice on how to go about testing the SC board to make sure things are ok before installing the new bits would be greatly appreciated.
2/
Testing the SU and SD buffers to be sure they're ok and not going to cause a problem once the repaired SC goes in.
Have seen the googletube vids on checking buffers in general but my tv currently has the buffers installed and the rear cover is on so i can't get at them right now, but if removing them for further testing is essential then i'm happy to.
Will post below some of the checks i've already done and the results. They were done using a cheapo meter more than a month ago- i'll double check them with a better meter and post back anything noteworthy when i get the tv out again but i think it was accurate enough and there shouldnt be much different.
The driver ic's leads when probed seemed to match the schematic with no shorts and the other components around the area apart from the mentioned ones seem to be ok, but I'm afraid of missing something else.
p5v is stable without the SC board attached so my focus is on getting the sc su sd sorted.
I plan on first power-up to leave the su and sd disconnected and make sure the sc board led is working, make sure the p5v is stable etc. I dont see why it would be, but if this is a bad idea pls let me know.
I have many manuals etc (even got lucky and found the schematic for this exact model)and have done most of the tests suggested in them, and then some. But would really like to hear from ppl who have been down this path before to be as sure as i can be, before putting in new parts and crossing my fingers like i kinda would be now.
Any other tips or suggestions on what you might do in this situation etc are also welcome, I am no repairman or engineer who thinks he knows better. If things work out I plan to keep it for personal use just at movie times. For an always on in the background tv I'm sticking with my current 32" led backlight dealy which uses about 1/4 as much power.
Thankyou all, great info here.
Related info:
(Sorry not actual links, but can be copied/pasted/googled easily)
panasonic_th-p42s10a_chassis_gpf12da.pdf (*not actually sure if the gpf12da part matches my tv, but the rest is correct)
panasonic 12th or 13th generation plasma tech guide
And another link to this very helpful thread which if you're reading this, you should find of interest if you have not already:
https://www.badcaps.net/forum/showthread.php?t=27921
image 1: SC Measurements
image 2: SU SD
image 3: Highlighted schematic of problem area. Red is tested bad. Yellow i think i just marked as suspect but tested ok later. Will verify that.
SC board - TXNSC1EKUU / TNPA4829AD
Description of SOS 5 blinks from Panasonic manual:
"5 Blinks SOS: Pin 60 of the CPU IC9003 monitors the 5V line. During normal operation, pin 60 is kept high. If the 5V line is missing or shorted, a low is provided to pin 60. As a result, the unit shuts down and the power LED blinks 5 times."
TV symptoms at first test:
When powered on there is a relay click followed by a transformer hiss(not buzz or humm, a clear hissss) for approx 3 seconds before the relay clicks again and the unit powers down and begins 5 blink led code (sos-p5v).
No image displayed at any time. No other blink codes, just 5, 5, 5 etc.
P5v measurement at pin 5 or 6 of P25-A25 during brief 3 sec power on period rises to approx 4.59-4.61v before falling back to 0 as unit powers off again. Not stable, never reaches 5v, always gradually rises to approx 4.6 on repeated attempts before unit powers down again.
SS board LED not working. SC board LED not working.
With SC board disconnected from power between P2 - SC2, and also ribbon disconnected between A20 - SC20 - the unit powers on for a slightly longer period (approx 5 secs) and p5v measurement taken during power on period at p25 shows quite stable 4.95v until unit powers off and begins 6 blink led code. The hissing from the transformer on the P board also goes away. Good good - Stable 5v is present between P-A boards, and A board is successfully detecting that the SC board is disconnected. (with SC board re-attached, the unit resumes 5 blink code)
With the SC board disconnected the SS board LED is also now working and switched on. Good. Disconnecting the SC(and SU/SD effictively) seems to have removed the shorting p5v..
With SC board disconnected, measured voltage of tp-vsus (located on SS board just below S11-P11 power connector)using safe insulated clamp type test leads reads same as internal calibration sticker suggests, in my case 209v on sticker, 208-210 measured. ok.
With SC board disconnected, measured TP-VE located on SS board lower right. 140v on sticker and 139.8 measured. ok.
On to the disconnected SC board -
Resistance measurements probed on SC board components in circuit - unplugged from mains and caps carefully discharged via large 5w ceramic resistor before starting:
Q401, Q402, Q421, Q422, Q661 (all TO-220 on heatsinks)& D865(smt, located upper left of board between 2 heatsinks) showing shorted/ continuity in all directions. bad. This is also where i stumbled into other handy threads after googling Q401 shorted tnpa etc - that made finding the rest as easy as following a guide and sure enough, each component mentioned in this thread by the folks who have fixed them was reading dead shorted in all directions.
Have tested and found bad components on SC / y-main mostly identical to the users in this thread, but didn't want to hijack: (*big thankyou's to all here)
https://www.badcaps.net/forum/showthread.php?t=27921
Bad Q401, Q402, Q441, Q442, Q661, D865
I have removed the failed bits from the SC and have the replacement parts ready to go in after waiting some time for delivery, but before i do i wanted to ask for some advice on 2 things in particular:
1/
Before installing the new components on the SC board I would like to test with some degree of certainty that it is otherwise free from other failed bits or shorts etc. Any advice on how to go about testing the SC board to make sure things are ok before installing the new bits would be greatly appreciated.
2/
Testing the SU and SD buffers to be sure they're ok and not going to cause a problem once the repaired SC goes in.
Have seen the googletube vids on checking buffers in general but my tv currently has the buffers installed and the rear cover is on so i can't get at them right now, but if removing them for further testing is essential then i'm happy to.
Will post below some of the checks i've already done and the results. They were done using a cheapo meter more than a month ago- i'll double check them with a better meter and post back anything noteworthy when i get the tv out again but i think it was accurate enough and there shouldnt be much different.
The driver ic's leads when probed seemed to match the schematic with no shorts and the other components around the area apart from the mentioned ones seem to be ok, but I'm afraid of missing something else.
p5v is stable without the SC board attached so my focus is on getting the sc su sd sorted.
I plan on first power-up to leave the su and sd disconnected and make sure the sc board led is working, make sure the p5v is stable etc. I dont see why it would be, but if this is a bad idea pls let me know.
I have many manuals etc (even got lucky and found the schematic for this exact model)and have done most of the tests suggested in them, and then some. But would really like to hear from ppl who have been down this path before to be as sure as i can be, before putting in new parts and crossing my fingers like i kinda would be now.
Any other tips or suggestions on what you might do in this situation etc are also welcome, I am no repairman or engineer who thinks he knows better. If things work out I plan to keep it for personal use just at movie times. For an always on in the background tv I'm sticking with my current 32" led backlight dealy which uses about 1/4 as much power.
Thankyou all, great info here.
Related info:
(Sorry not actual links, but can be copied/pasted/googled easily)
panasonic_th-p42s10a_chassis_gpf12da.pdf (*not actually sure if the gpf12da part matches my tv, but the rest is correct)
panasonic 12th or 13th generation plasma tech guide
And another link to this very helpful thread which if you're reading this, you should find of interest if you have not already:
https://www.badcaps.net/forum/showthread.php?t=27921
image 1: SC Measurements
image 2: SU SD
image 3: Highlighted schematic of problem area. Red is tested bad. Yellow i think i just marked as suspect but tested ok later. Will verify that.
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