Sharp QT27 Boombox has no sound Can I fix it as a favour? | UK eBay Reseller

This Sharp QT27 boombox/portable stereo has no sound from the radio or tape player. This was given to me by a subscriber to the channel and friend in the eBay reselling community John YLM. This one I was trying to fix as a favour to John for doing me a cheap deal on a load of broken items I purchased from him. Let's try and save this old machine.
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[@RoughJustice2k18]

I have this model in dark blue (mine has a fine tuning knob). I first got it early 2020 and it had the same problem with audio. From experience I've discovered with a few of these budget boomboxes that the REC/PB switch on the main board develops high resistance (due to oxides and/or dirt building up over the years) - and sometimes the radio/tape switch goes flaky too, possibly muting the sound, so cleaning these helps. I used approved electronic control and switch cleaner (not household WD-40). The tape deck in mine just needed a new belt and routine service.

[@RetroElectronicRepair]

I checked all the resistance of the PB/Rec bar and it has no resistance apart from the 2.2k resistor which measures correctly. The WD-40 I used is a contact cleaner, which is very good, it's not the normal WD-40 which I would never use on electronics.

[@RoughJustice2k18]

@@RetroElectronicRepair Being a basic model, there would be no sense wasting any more time on it than necessary. I'm glad you quit going too much further on this one before it got silly and expensive but at least you got the radio working.😎

[@RetroElectronicRepair]

Yeah, I was only doing this one as a favour for a friend, so didn't want to waste too much time on it. Someone has sold this model though for £100 on eBay and I have sold one in the past for £45 so they're definitely worth looking at.

[@RoughJustice2k18]

@@RetroElectronicRepair By contrast, I recently got a (black) Sharp GF-A1 which had power, but no sound at all (radio or tape). After looking over the whole main board assembly (pretty compact with the tuner and amplifier built into it) and replacing no less than five bad capacitors, along with the usual dry solder joints, I was rewarded with loud, clear, stereo audio output from the tape deck (via headphones) but weak / low / distorted sound from the radio on AM band (FM doesn't work at all) - in this model the radio should be roughly the same volume level as the tape deck. Not going to bother trying to fix it as FM tuner failures are common with Sharp boomboxes from the early to mid 1980's (and I have other units which are better and work great). I did however, replace the belts in the tape deck and adjust the speed. It will simply be a tape player at this point. Finally, after watching this video, I took the plunge, liked it and subbed to you.😇

[@odellcreations]

I have an Xbox one that shut down during gameplay and won't come back on. I ordered a power supply brick for it from Amazon. The light stays orange with a short flicker to yellow or green when I power on the Xbox but it immediately shuts back off and the light returns to orange. I have tried all the usual reset brick stuff as well. The Xbox will simply make the power on noise but won't come on. Did I get a faulty power supply from Amazon or is there something wrong in the mother board. I have also taken it apart and blew out all of the dust. I am somewhat savvy with electronics. I have some experience in soldiering and replacing components on circuit boards as well as computer experience and usually can fix anything myself. But I haven't been messing with Xbox since the 360 series and you seem to be experienced with them. I would love to hear your opinion on what you would suspect first and what steps to take in testing it? Thanks in advance. Hope to hear back soon!

[@RetroElectronicRepair]

Take a look at this video kzbin.info/www/bejne/j2rbmHWLgcyKZs0si=aPv_qTocdmCFPpA_ it could be a bad MOSFET on the 12v power rail.

[@odellcreations]

@@RetroElectronicRepair thanks for the prompt reply. Mine doesn't have the Xbox light ever come on like that one does. It just makes the beep and back off, no light on the Xbox but the orange light flickers to yellow for a split second when I attempt to power it on. I am currently watching this video for a second time. Thanks.

[@RetroElectronicRepair]

If the light isn't coming on at all it does suggest a MOSFET on the 12v rails.

[@odellcreations]

@@RetroElectronicRepair thanks. I don't have a hot air rework station nor a spare board to take a mosfet from, but I was thinking it was probably in that area. I found a blown cap right next to one of the mosfets.