Panasonic CT-32HX40B H.O.T. problem
I have a Panasonic CT-32HX40B HDTV. Some time ago, the flyback
transformer died, and I replaced it. Since then, there is no picture when I turn the TV on. I know it's tuning the channels correctly because I can hear the channel's audio through the speakers. I thought to check the horizontal output transistor and found that the base and emitter are both shorted to ground. Does anyone know what could cause this, or what components to check? Any information would be a great help. Thanks, Adam Dorsey |
Panasonic CT-32HX40B H.O.T. problem
On Jul 25, 10:05 pm, wrote:
I have a Panasonic CT-32HX40B HDTV. Some time ago, the flyback transformer died, and I replaced it. Since then, there is no picture when I turn the TV on. I know it's tuning the channels correctly because I can hear the channel's audio through the speakers. I thought to check the horizontal output transistor and found that the base and emitter are both shorted to ground. Does anyone know what could cause this, or what components to check? Any information would be a great help. Thanks, Adam Dorsey Video and horiz blanking circuits |
Panasonic CT-32HX40B H.O.T. problem
On Jul 26, 7:44 am, "Mark D. Zacharias"
wrote: wrote in message ups.com... I have a Panasonic CT-32HX40B HDTV. Some time ago, the flyback transformer died, and I replaced it. Since then, there is no picture when I turn the TV on. I know it's tuning the channels correctly because I can hear the channel's audio through the speakers. I thought to check the horizontal output transistor and found that the base and emitter are both shorted to ground. Does anyone know what could cause this, or what components to check? Any information would be a great help. Thanks, Adam Dorsey Base-emitter junction would normally read shorted because of the drive transformer. Even out-of-circuit most HOT's have a 47 ohm resistor internally across the E-B junction. Your problem is elsewhere - maybe a 200 volt line down. You can check the voltages at the driver transistors on the crt board. Mark Z. Thanks for the info. I probably wasn't clear enough when I said this. The transistor is fine; what's shorted is the base and emitter pads on the board itself. It seemed weird that both pads were shorted to ground on the board. The pads are laid out like this: o C B-o o-E and B and E are both shorted to ground. Is this normal? |
Panasonic CT-32HX40B H.O.T. problem
Reading across the windings of the h-drive transformer will give you a
moderately low resistance reading. wrote in message oups.com... On Jul 26, 7:44 am, "Mark D. Zacharias" wrote: wrote in message ups.com... I have a Panasonic CT-32HX40B HDTV. Some time ago, the flyback transformer died, and I replaced it. Since then, there is no picture when I turn the TV on. I know it's tuning the channels correctly because I can hear the channel's audio through the speakers. I thought to check the horizontal output transistor and found that the base and emitter are both shorted to ground. Does anyone know what could cause this, or what components to check? Any information would be a great help. Thanks, Adam Dorsey Base-emitter junction would normally read shorted because of the drive transformer. Even out-of-circuit most HOT's have a 47 ohm resistor internally across the E-B junction. Your problem is elsewhere - maybe a 200 volt line down. You can check the voltages at the driver transistors on the crt board. Mark Z. Thanks for the info. I probably wasn't clear enough when I said this. The transistor is fine; what's shorted is the base and emitter pads on the board itself. It seemed weird that both pads were shorted to ground on the board. The pads are laid out like this: o C B-o o-E and B and E are both shorted to ground. Is this normal? |
Panasonic CT-32HX40B H.O.T. problem
Thanks for all the help guys. I think I've found the problem and will
be doing more checking tomorrow (it's late). Thanks again for all the info! |
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