Philips 20in television, model 21PT/4457/05

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exsweb
Philips 20in television, model 21PT/4457/05

My TV will not receive commands from the remote control.  I have tried a spare remote (set to the appropriate code), but this will not work either.  If the fault lies in the television R/C receiver, can anyone help by advising where I can obtain a spare unit or supply any info on what component(s) I may need to replace?

Larry Dillon
what about the front panel

what about the front panel buttons?  Does the power go on there?

exsweb
Yes, the channel selector and

Yes, the channel selector and the on/off controls on the set work normally.

Larry Dillon
Ok,  your problem is a bad

Ok,  your problem is a bad remote sensor, the connections from the sensor to the microprocessor IC, or the microprocessor IC is bad.  The only way to  trouble shoot this set is to use an ocilliscope.  You would have to press on the remote buttons and monitor the data output line on the sensor for data.  If only noise or nothing was comming out of the data line on the sensor,  Then the sensor would most likly need to be replaced  You would then, if the unit had good data on the output, trace the printed circuit landings all the way to the microprocessor.  If the signal was good up to this point, the micro would most likly be the culprit.  let us know if you have it fixed and what they did to fix your problem.  Good Luck

exsweb
Thanks for your reply.  Your

Thanks for your reply.  Your diagnosis compares with that of a tv service engineer I used to know well and happened to bump into yesterday - the first I had seen of him for years!

I do not have a 'scope and I do not know enough about microprocessors to tackle that. However, if I can get hold of a remote receiver unit to replace the one in my set, I would like to try this. I suppose it would have to be Philips to match the code of my philips remote control.

Just one more point. The receiver unit must contain an infrared receiver component (photodiode or similar), is there a small chance that this may be faulty? 

Larry Dillon
anything is possible, but

anything is possible, but most of the time those remote sensors are not worth repairing as there are no parts available.  Oh BTW, I cant find your model number under US or UK support?

exsweb
When I enter this model

When I enter this model number on google,  product number as above comes up with details, but it looks as if the first forward slash should be omitted,(21PT4457/05). Appologies for wrong screen size - should be 21in.

 

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