Oh yeah..that's a common problem caused by the
small inductors
in the read amplifier going open. too much stress on the leads.
Add a couple of years and bingo no read.
I've never had _that_ problem, but doubtless I will sometime...
One thing I forgot to mention last night is that another very common read
circuit uses the MC3470 chip. If you have one of those in the drive, it's
certain to be the read chain.
-tony