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My first attempt at SMD repair. How would you do it?
My first attempt at SMD repair. How would you do it?
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Old 21st September 2019, 06:44 AM   #11
Mooly is offline Mooly  United Kingdom
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My first attempt at SMD repair. How would you do it?
If the outputs have failed then its 99.9% certain they will be reading almost short circuit from collector to emitter.

uP's are difficult (impossible) to verify on a one off basis although you can make an informed decision. Check the supplies are correct and check that the clock/oscillator is running and that any reset pins are released. Go around all pins on the chip with the scope looking for both DC voltages and any AC data that may be present and decide if it looks 'reasonable'. For example seeing 5 volts peak/peak of data on any relevant pins is a good sign, seeing perhaps a pin stuck at some indeterminate voltage with say a couple of 100mv of data riding on it might have you questioning and looking further.

Generally uP's are extremely reliable and 99% of issues lie elsewhere.

Also use a DBT (dim bulb tester) when powering the amp up, particularly if you have done any component replacements in the power amp sections.
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Old 21st September 2019, 08:51 PM   #12
StewartH83 is offline StewartH83  England
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Your a great help indeed,

I will step up and start investing in some good testing equipment as the hobby is not going away

I have lent him my Denon PMA250III for now and he loves it. Thinking he may not be as attached to this Pioneer now.

I can understand as he bought it new before going to Afghanistan and getting a head injury.

I will check output transistors later for continuity. I have a multimeter in the post

Thanks for your detailed reply as this will be good info for the future I'm sure
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Old 22nd September 2019, 06:38 AM   #13
Mooly is offline Mooly  United Kingdom
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My first attempt at SMD repair. How would you do it?
OK, good luck
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