Broken Plasma TV (Need a bit of help troubleshooting + identifying part)
Model: Samsung HP-S4253
Well, I broke my plasma thanks to me using a metal screwdriver to adjust a pot (Y-FR), but missed and hit a resistor + grounded heatsink instead. Once that happened I got a big spark. After that the panel had tons of "sparklies", or red/green/blue pixels that flash all over the screen, which looks a bit like static. The colors for the picture are somewhat off and have some vertical banding, which makes me think the panel is now being overdriven.
The pot that I was attempting to adjust appears to no longer change anything on the screen as it used to, however the other 2 pots on the upper part of the board still function.
I thought I identified the problem as being a bad MOSFET since doing the diode/resistance measurements on the one closest to the pot versus an identical one on the board near the other pots gave different results, and when the TV was on the heatsink was barely warm while the others are quite hot. So I got a close enough replacement to it, fired it up and not much changed in the picture or the heatsink temp.
The resistor I hit with the screwdriver is a surface mount '3R0'. I checked the value in-circuit and got a reading of over 4 MegaOhms, which is way off from where it should be. I also disovered a zener diode close by that gives a shorted reading on the multimeter (0.000v). The pot reads the same range as the other ones which are identical, ~0.3ohm to ~1kohm (~ = approximately).
I have read that testing resistors in circuit may not be reliable, though all of the other surface mount resistors read as they should except for one other that was marked '104', which was also off by a large amount.
The questions I have so far are:
1. Is testing resistors in-circuit reliable? What about MOSFETs? What about diodes?
2. The zener diode has color bands on it, how can I identify what replacement part I need based off that. I tried looking up parts based on the number/letter combo chart I found online but that yielding nothing on mouser.
Sorry for the long and probably confusing post, it's a bit hard to condense it all. If pictures or more info is needed let me know.
Thanks!
Well, I broke my plasma thanks to me using a metal screwdriver to adjust a pot (Y-FR), but missed and hit a resistor + grounded heatsink instead. Once that happened I got a big spark. After that the panel had tons of "sparklies", or red/green/blue pixels that flash all over the screen, which looks a bit like static. The colors for the picture are somewhat off and have some vertical banding, which makes me think the panel is now being overdriven.
The pot that I was attempting to adjust appears to no longer change anything on the screen as it used to, however the other 2 pots on the upper part of the board still function.
I thought I identified the problem as being a bad MOSFET since doing the diode/resistance measurements on the one closest to the pot versus an identical one on the board near the other pots gave different results, and when the TV was on the heatsink was barely warm while the others are quite hot. So I got a close enough replacement to it, fired it up and not much changed in the picture or the heatsink temp.
The resistor I hit with the screwdriver is a surface mount '3R0'. I checked the value in-circuit and got a reading of over 4 MegaOhms, which is way off from where it should be. I also disovered a zener diode close by that gives a shorted reading on the multimeter (0.000v). The pot reads the same range as the other ones which are identical, ~0.3ohm to ~1kohm (~ = approximately).
I have read that testing resistors in circuit may not be reliable, though all of the other surface mount resistors read as they should except for one other that was marked '104', which was also off by a large amount.
The questions I have so far are:
1. Is testing resistors in-circuit reliable? What about MOSFETs? What about diodes?
2. The zener diode has color bands on it, how can I identify what replacement part I need based off that. I tried looking up parts based on the number/letter combo chart I found online but that yielding nothing on mouser.
Sorry for the long and probably confusing post, it's a bit hard to condense it all. If pictures or more info is needed let me know.
Thanks!
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