8-bit acorn hardware • Re: General advice requested

Amazingly I think I might have fixed this on my own! I did some googling at work today (don't tell the boss) and found this page: http://bbc.nvg.org/doc/A%20Hardware%20G ... _hw_06.htm This says the the DC offset voltage measured at pin 1 of IC35 should be no more than 100 mV, but I measure mine at 545 mV! On the board that was loading tapes better it was only -65 mV (I was a bit confused about it…