Crane Song Spider PSU repair

[jhaell]

I have this CS Spider PSU in for repair. All voltage rails deliver the correct voltage, however, the phantom rail can only supply 0.3ma at each mic input. I have narrowed it down to the PSU, since the same fault appears on three different preamp units.

I suspect a voltage regulator is at fault, but before (ordering a new one) and changing it I would like to check if anyone has any kind of documentation on these PSUs? I could trace it out, but I don’t really have the time.. I’ve contacted Crane Song but I haven’t heard back yet. Any help would be welcome.

Edit: Just heard back from Dave Hill, I’ll be able to fix it now that I have the schematic.

 

[Ike Zimbel]

Just FYI, correct voltage but very little current can, at least in my experience, be either an incorrect value resistor (like 10x or 100x or 1000x the correct value...I've seen that on at least one console power supply, and one DIY build I was asked to sort out) OR a resistor(s) that have gone off value. I saw this once on the 48v on a dbx pre-amp, I forget the model, maybe a 386?. The 6K81 resistors, both SMD types had gone up to 20k or something. Even more fun, this still worked fine with the SDC (a Crown CM-700) that I had on the bench for testing. It wasn't until I borrowed an LDC that I could get the "doesn't work with phantom power" fault to appear.