hi
Elecetronics novice here
have a Sharp tv on the above model.
Having problems in not able to get all the channels (i.e i live in Aust,melb)..currently i can only see one channel Properly(SBS).
Have open the Tv and resoldered all the joints ,have opened up the RF tuner(silver mettalic box)
and resoldered all the small joints as well.
Doing all this has not solved the problem yet.
Could someone shed some light on what the problem might be...is it a capactior or soemthing else..whre should i look?
Any help would be good.
Cheers
Ash
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There are several issues could cause this resistors R236/1031/1039 and inside the tuner you will find neaar where the antenna plugs in there's little wire coils, resolder these. They will look fine but the solder can take on strange properties so dont look and say no its OK. Also cant remember if its digital tune or not, think its not, check when you sarch on VT pin if it rises. May have the diag in PDF if needed buzz me at hotmail.com
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Im too far away, I think your tuner is out, would probably cost $80 think from Speedy Spares Kensington but theres a fair risk its not and the micro is faulty. Nearest descent fixer to you is Future world Electronics 318 Centre rd Bentleigh
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the Zener you are concerned with near the tuner probably is an IC. Measure the voltage when on, should be stable about 33V. A standard zener wont do there. You can build it by using several zeners in series, one must me 5.6V or under one must be 6.8V or over The dif is one is an avalanche diode the other is a zener, both get called zeners but they do different things as they heat up.
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if the micro is faulty ..where is this located at in the ciruit?...
is this cheaper then the tuner to replace?..
The diode near the tuner measures 33V when on power..so i take it that this is not faulty.
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Ok pulled out diag and had a look, its not a digital tuner so its easier. Now you are going to have to read voltages on the tuner and do a search tune whilst the set is on so figure out how to do that. Next get the set tuning check on pin B, I think its 9V now with the set tuning check on BL BH and U. now here you should have voltage, when BL is tuning BL is 9V if BH is tuning BH is 9V BL bay be as well then when UHF is tuning that pin gets voltage. and the last check is VT. that should go from about zero to 30V as it tunes up the band. If it does all that, the tuner is stuffed. If the set has AV in dont waste your time, buy a cheap set top box and tune that. If the micro is stuffed you wont get that, its marked Upro or sonething like that its IC1001.
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Ok pulled out diag and had a look, its not a digital tuner so its easier. Now you are going to have to read voltages on the tuner and do a search tune whilst the set is on so figure out how to do that. Next get the set tuning check on pin B, I think its 9V now with the set tuning check on BL BH and U. now here you should have voltage, when BL is tuning BL is 9V if BH is tuning BH is 9V BL bay be as well then when UHF is tuning that pin gets voltage. and the last check is VT. that should go from about zero to 30V as it tunes up the band. If it does all that, the tuner is stuffed. If the set has AV in dont waste your time, buy a cheap set top box and tune that. If the micro is stuffed you wont get that, its marked Upro or sonething like that its IC1001.
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