Sony Microcassette M330 overheating
I am having a go at fixing this little machine for an older lady who wishes to play her old micro-cassette collection.
I somehow feel it's a bit beyond me as it's all surface mount and no manual but I have the fault of seemingly no operation, so I tried on my bench PSU. I see that the Voltage (3) is dragged down to around 2 at 500mA limit with the power amp IC getting hot. Nothing operates nor does the motor turn. It's this one. https://www.nisshinbo-microdevices.c.../NJM2073_E.pdf I checked if it was short internally - it isn't. I checked if the output was shorted - again, it isn't. There was some heavy brown flux on the trace side of the PCB around many of the solder joints which I cleaned off leaving an odd remnant of white gummy stains. I'm wondering if components may have been damaged by this. Thanks for any ideas. If I can't fix it I will just return to her but I want to try. |
Re: Sony Microcassette M330 overheating
The problem is likely very near the power input. Short in a dc socket? Probably simpler to pick up another one online, they're cheap enough.
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Re: Sony Microcassette M330 overheating
Does it contain tants or types of caps that can fail short circuit?
MLCCs, especially SMT types, can fail this way. |
Re: Sony Microcassette M330 overheating
I have the paper service manual for this model that I could scan and email to you. If it's of any help PM me with your email and I'll get it scanned in the next couple of days.
Dave |
Re: Sony Microcassette M330 overheating
Thanks for the input. I checked for tants but only a few electrolytic ones which read OK.
I'm actually running from the battery supply with flying leads. This evening I will lift the DC input leg on the amp - see if that helps. Dave, the service manual would be appreciated. I'll pm you. Yes I thought straight away of suggesting a working replacement but I'd at least like to try. I'm interested in what could be wrong. |
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