My Revox A77 four track tape recorder, is back on my repair bench.\n\nI played a tape last week and everything was fine. A few days later I went to play another tape, and on switching on all the reel motors spun, and then the main fuse blew.\n\nI bought this machine as a restoration project about twenty years or so ago. I had to be patient as I had to find the NLA oscillator IC for the capstan drive. This took many months to locate.\n\nThe A77 was produced from 1967 to 1977. It had four iterations, the MK I, MK II, MK III and MK IV. I have restored MK I, MK III and this MK IV. I have a MK II, but confess I have never got round to doing the restoration. The MK IV was produced from 1973 to 1977. The MK I was the world's first solenoid operated tape transport, and used at Abbey Road to record the Beatles' Sergeant Pepper album. This was the first major recording made with a tape deck that did not have an entirely mechanical transport.\n\nThe A77 MK IV is the deck on the right of the Cassette deck and the Brenell MK 6 id on the right of it.\n\n\n\nHere is the machine on the bench. The layout is organized and modular, and not in any way a "bird's nest" of wires and cables.\n\n\n\nThe problem seems to be on the solenoid transport control board. One of the motors starting caps, seems to have shorted and burnt out its accompanying 4.7 ohm resistor.\n\n\n\nHopefully parts will be here this week. I will replace all three motor starting circuits. Hopefully that will do the trick.\n\nThis older caps, were aluminum\/paper. I have ordered more modern aluminum\/polypropylene X2 rated safety caps.\n\nSo, I hope that does the trick.