hi,
i'm a user of old tx-p42s20e and recently was lurking for some replacement. after month of searching and reading forums the conclusion is that in reasonable price there is nothing better than old good panasomic plasma. so i've triggered hunt on some latest/highest models and found one for bargain. it's subject VT50 after lighting storm
from seller i've got info that lighting was quite close to his house, precisely right at neighbour, and additionally stb hdmi port was malfunction after it.
after transportation to my home the initial issue was 3 blinks. i've removed back cover and there was no single indication of lighting on any board.
i've already had hit of lighting in my p42s20 and that was through the eth cable. the trace was easily spottable as breaking between paths close to eth chip. i've replaced A-board and TV relive.
so, checked the tsg guide for 2012 plasma and found this is interrupted boot procedure. that could means anything from eeprom corruption to main peak p4 burnt. i've checked power board and the supply of 15V was there on other side for a moment. also inspected what happen during boot time using termal camera and the A-board was hot only for short period at 3.3V VRE north close to SS buffer port (IC8705 if i see correctly).
meanwhile i've found the A-board for this set is quite rare on secondhand market. also prices are high, x2 if not more than for example ST50. so, after conclution this is definitely A-board i've searched for it on local ebay but none. more advanced TSG for me would be problematic as i don't own a regulated voltage supply. but apparently when searching for circuit number instead of exact revision i found one exposed for sale just same day. it was one from TX-P42GT50, TXN/A1SQUE instead of TXN/A1SJUE. after just eye inspection the only difference seems to be missing fan port and fan driver plus some 3 additional caps close to hdmi ports. i've made a bet.
after getting it in my hands i've initially connected it and vuala, the TV is working. happy with that i've decided to prop the fan control, fan port and suffix jumpers to new board making it barely same to original. that was not easy as lot of tiny smds but with help of hot air i've managed to do it right with only first try. that was surprising to me i must admit
ok, one would say end of story, i've tested TV at my workbench for few hours and OK, the only what left was to change of model id using eeprom editor to the right one. as i had to search for other user of such nowdays rare TV and that was not so easy i'd assembled back cover and moved TV in place of old good early-retired S20 one.
but that's not the end of story, first ON at saloon and after minute or so 8 blinks of death. wth i thought? what a fail, my family proud and eager to test it up and this.
ok, dismounting again and this time all traces goes to SS board. sometimes it works well, voltages seems ok, but somehow after random period death. i can see that the indication of bad happening is green led dimming. it could dim lightly but when dims more than 8 BOD instantly. also when SS board disconnected from A-board everything is working, i'm able to start netflix (thanks to some artifacts on screen) and no 8 blinks. i could hear voice and so but no picture as SS board is in some off mode, just half of voltage (~60V) at output of TPSS1 compared to normal operation (~125V).
and again, what i could do i had done. as this seems to be some bad joint i've used hot air and reflow ICs and FETs on SS1. that helped for few hours but next day 8 BOD as well. not wasting more time i've found similar SS board (again not from 55VT50 but 50VT50) from local ebay for $20 and now TV is working.
however, and that's the point of above long post, the 50VT50 SS board is slightly different and i supposed able to carry lower current. there is missing one FET, Q16023 (30F132) on the path from main L out to SS2, the large caps at north are 250v260uF instead of 220v300uF as in original. the buffer ICs are different, there is IC152 instead of IC153 and so on. at original i have those all buffers different than with replacement board. i supposed IC153 at original as reason of that intermittent failure (recovery low buffer) but don't know how to prove it. finally, some small caps and few heat sinks in other places are +/- (see 2nd picture)
and the question what to do? add Q16023 from original to good board to increase current capacity, or just remove IC16153 from bad one and add the IC16152 and test? or do nothing and wait if it burns replacement SS?
[in attachment is old SS (dismounted one) and replacement (pic with part of fan)]
regards
piotr
i'm a user of old tx-p42s20e and recently was lurking for some replacement. after month of searching and reading forums the conclusion is that in reasonable price there is nothing better than old good panasomic plasma. so i've triggered hunt on some latest/highest models and found one for bargain. it's subject VT50 after lighting storm
from seller i've got info that lighting was quite close to his house, precisely right at neighbour, and additionally stb hdmi port was malfunction after it.
after transportation to my home the initial issue was 3 blinks. i've removed back cover and there was no single indication of lighting on any board.
i've already had hit of lighting in my p42s20 and that was through the eth cable. the trace was easily spottable as breaking between paths close to eth chip. i've replaced A-board and TV relive.
so, checked the tsg guide for 2012 plasma and found this is interrupted boot procedure. that could means anything from eeprom corruption to main peak p4 burnt. i've checked power board and the supply of 15V was there on other side for a moment. also inspected what happen during boot time using termal camera and the A-board was hot only for short period at 3.3V VRE north close to SS buffer port (IC8705 if i see correctly).
meanwhile i've found the A-board for this set is quite rare on secondhand market. also prices are high, x2 if not more than for example ST50. so, after conclution this is definitely A-board i've searched for it on local ebay but none. more advanced TSG for me would be problematic as i don't own a regulated voltage supply. but apparently when searching for circuit number instead of exact revision i found one exposed for sale just same day. it was one from TX-P42GT50, TXN/A1SQUE instead of TXN/A1SJUE. after just eye inspection the only difference seems to be missing fan port and fan driver plus some 3 additional caps close to hdmi ports. i've made a bet.
after getting it in my hands i've initially connected it and vuala, the TV is working. happy with that i've decided to prop the fan control, fan port and suffix jumpers to new board making it barely same to original. that was not easy as lot of tiny smds but with help of hot air i've managed to do it right with only first try. that was surprising to me i must admit
ok, one would say end of story, i've tested TV at my workbench for few hours and OK, the only what left was to change of model id using eeprom editor to the right one. as i had to search for other user of such nowdays rare TV and that was not so easy i'd assembled back cover and moved TV in place of old good early-retired S20 one.
but that's not the end of story, first ON at saloon and after minute or so 8 blinks of death. wth i thought? what a fail, my family proud and eager to test it up and this.
ok, dismounting again and this time all traces goes to SS board. sometimes it works well, voltages seems ok, but somehow after random period death. i can see that the indication of bad happening is green led dimming. it could dim lightly but when dims more than 8 BOD instantly. also when SS board disconnected from A-board everything is working, i'm able to start netflix (thanks to some artifacts on screen) and no 8 blinks. i could hear voice and so but no picture as SS board is in some off mode, just half of voltage (~60V) at output of TPSS1 compared to normal operation (~125V).
and again, what i could do i had done. as this seems to be some bad joint i've used hot air and reflow ICs and FETs on SS1. that helped for few hours but next day 8 BOD as well. not wasting more time i've found similar SS board (again not from 55VT50 but 50VT50) from local ebay for $20 and now TV is working.
however, and that's the point of above long post, the 50VT50 SS board is slightly different and i supposed able to carry lower current. there is missing one FET, Q16023 (30F132) on the path from main L out to SS2, the large caps at north are 250v260uF instead of 220v300uF as in original. the buffer ICs are different, there is IC152 instead of IC153 and so on. at original i have those all buffers different than with replacement board. i supposed IC153 at original as reason of that intermittent failure (recovery low buffer) but don't know how to prove it. finally, some small caps and few heat sinks in other places are +/- (see 2nd picture)
and the question what to do? add Q16023 from original to good board to increase current capacity, or just remove IC16153 from bad one and add the IC16152 and test? or do nothing and wait if it burns replacement SS?
[in attachment is old SS (dismounted one) and replacement (pic with part of fan)]
regards
piotr
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