I've been using it untouched for eons. As a data grave that I only ever power up when I want to access my archives and backups. With all four spinning rust drives running it consumes 40W. With the spindle motors off, this drops to less than 27W.
I broke my little function generator, a Maxcom MX-2020. Used it for sweeping the AM radio and while working on that late at night I accidentally connected it directly to some spicy point in the radio. You want a capacitor in between to block DC voltages, but it fell off the croco cables and I didn't notice. The Maxcom saw about 160V DC at its input. It really didn't like that.
So far for the obvious damage. After replacing these parts, it still did not work however. Checking the supply voltages: it has two 5V rails, one is used for the front panel display, the other however, independent of the first, is used to supply the actual signal generation part. It sat at 1.8V. R131, the big 5W resistor, got really hot. It had a voltage drop of over 12V across it. First instinct was to check the voltage regulator U6. It checked out fine. So something was pulling this rail low.
U23, the CA3046 transistor array to the bottom left, wasn't properly soldered in. So this was one of the first things I fixed. I of course socketed it, which meant that taking it out of the circuit was a no brainer. Not the fault.
Q13 and Q14 also checked out fine. Next instinct was U14, the SN75107 line reciever. I've seen a lot of bad 75 series parts. Taking it out of circuit didn't bring the rail back to 5V either.
Q13 and Q14 also checked out fine. Next instinct was U14, the SN75107 line reciever. I've seen a lot of bad 75 series parts. Taking it out of circuit didn't bring the rail back to 5V either.