Hello everyone, it's my first post so, I'd like to introduce myself . My name is Mateusz and I'm from Poland
I've bought not working Beocord 7000 recently. It wasn't turning on, but the problem was mechanically damaged fuse (wire wasn't burnt). After quick fix device started, I've replaced belts and tried to play some tapes, but here comes problem. As shown in the video: link (you may need to set 1080p quality by hand) motor spins but rest of mechanism don't move and it makes weird noises. I noticed that solenoids don't move at all, they aren't stuck and have reasonable resistance.
According to schematics from BO Beocord 6500 version 2 service manual (5 pages free version from web) I've checked timing charts with scope, and all I got was small voltage change (mV). I've also checked MCU reset pin (5V so ok), CASS DET (0V when tape inserted so ok). Next I've found that PROTECT pin is LOW (active), may that be the reason why circuit doesn't start? All semiconductors in this functional group are ok (TR31, 32, 35 D31, 32, 33 etc.) Voltages 5V, 14.8V, 12V 15.5V are also as expected. I don't really understand how protection circuit works (TR38, 37, 36), from my in head calculations PROTECTION net will always be high (pulling MCU pin via TR35 low).
It takes more force than I would expect to turn mechanism wheel, maybe after all those years grease got stiff or smth and MCU somehow detects it?
I would be grateful for any feedback, is there something I missed? Thanks for your time Mateusz