In 1988 I bought a 3D8 and had to return it back to Curry's for an under warranty repair and they couldn't fix it as it was shipped like it.
The fault was that it couldn't record on metal bias tape from new out the box.
Ffwd to a few years a go and I purchased a second hand one and one a guess what, same metal issue. The tapes were fine on the B&o and nakamichi decks, so knew it wasnt the tapes. Tried fully erasing them and demagging the heads, nope... same fault. I assumed Hitachi had a feature that was not supposed to be there.
So other week for £12.50 I dropped on a mint 3D7, the first one, and guess what, same issue... Whats the odds? Tried all above, even cleaning the selector switch and rec/pb switch... same issue, infact, it could penetrate deep enough to erase the previous recording.
Right, 4th time lucky in the form of the CX-W800, nay problem at all with any tapes for recording at all!! Best £50 I've spent ever, but I have two helpful tips here worth remembering.
1) If you get a fault where the volume controls do nothing but blare out even on min, well thats the wires to the graphic / vol board broken. Mine had a dead CD deck and I'd say with the force needed to separate the cabinets, it would be easy to break these wires.
2) Dead Cassette decks are the micro switches underneath dirty.
And the tweeters on the 800 are purely cosmetic hence the dual cone stereo speakers. Sweeter less harsh sound imho.
I'm a ex tv engineer so if you're not happy with electrics etc, don't take the back off or anything.