On Sep 20, 2016, at 12:49 PM, Julian Wolfe <j...@lolqb.us> wrote: > > > > So the DSD-440 I got at VCF is completely unresponsive. All of the LEDs are > on and never go out, which is bizarre - they are supposed to go out in 1/10 > of a second after power on. > > > I tried disconnecting everything but power to the card, and it still lights > all LEDs. No jumpers that I could find are in the wrong spot, but many are > seemingly undocumented ( I looked in both the 1981 user manual and 1984 > service manual on Bitsavers). > > > The drive just spins and does nothing else. Altering the switches on the > control board do nothing to change the state of the LEDs > I measured voltages at the power supply, and they seem to be within spec > according to the manual. > > > Are there any other things I can try before I start digging into things on a > component level? >
This is a failure of the DC Power Up/Down circuit - See page 3-10 + 3-53/54 in June 83 Service Manual. If the components in this circuit (capacitor) are out of spec, then this may be the cause. Congrats on picking it up. I was tempted to bid for it as well, but I already filled had my boat anchor quota. Is the Green LED on? Jerry
