28-03-2014, 09:21 AM
Whilst working on the above 20 year old midi HiFi, I found that, when I switched it on, having taken the metal oter cover of, none of the functions worked and the display was only partially visible. I had a jumper lead connected between the metal rear panel & the front metalwork (the cassette mech. chassis) although i couldn't see that any of the electronics used that as a ground. Checking with a multimeter, all points marked 'ground' were still earthed to the rear panel even without the earth jumper in place. Oh H*** I thought 'microprocessor failure' Anyway, I put the cover back on, switched the set on, and, to my relief, everything worked. The only odd thing no is that if 'Aux' is selected a flashing 'E' appears in the display, as it does if the unit is switched to standby. If the Deck 1/2 button is pressed 'ERROR' appears, but there is a mechanical fault in deck 1 anyway.
I've never had the above happen with any other modern processor controlled system. although I have had a few uP failures, despite wearing an earth strap and using an anti-static mat, so what was happening there?
To cap it all the reason I openend it in the first place was to service the CD Player.
Phoned CHS only to be told that the Laser PU is NLA!
I've never had the above happen with any other modern processor controlled system. although I have had a few uP failures, despite wearing an earth strap and using an anti-static mat, so what was happening there?
To cap it all the reason I openend it in the first place was to service the CD Player.
Phoned CHS only to be told that the Laser PU is NLA!
