-The first image is overall layout of the pcbs.
-Second is the red wire going from transformer "QC15" and "+15V" on the transformer pcb
-Third is that same red wire (on the right) connecting to the preamp pcb "P104" Also in that picture are the 3 wires going from preamp ("P101"(red), "P102"(black), and "P103"(blue))  to poweramp  ("CN2").
-Fourth picture is those same wires from a different view, showing how they connect to the poweramp pcb.
-Fifth is that black wire going from the big cap to underneath the pre control pcb
-And sixth is that double red lead that I believe to be the preamps power, clipped on both the transformer end, and the preamp control end.

As for fixing the power supply unit, I wouldn't know where to start. If you think you could help me with that, I'd much rather fix it than be ripping this whole thing up. If it helps, the pdf I attached looks like the schematic for the power supply. (I say looks like because I found it on another site labeled as "RG200 power supply," but not specifically for the RG200D. Not sure if that makes a difference; it at least looks pretty close. Thanks so much. Quick response times!

I'm trying to rip the preamp out of an old Randall RG200D combo amp, and I've got a few questions. The amp quit working a while ago, and I'm pretty sure the power transformer is shot. I don't know too much about amp anatomy, but I do know a little about electronics. That said, here are my questions. I know I'm quite novice, no need to flame- help is why I'm here.

1.) My ultimate goal is to remove the preamp section, and use it in conjunction with the poweramp of one of my other amps. To do this, I need to figure out all of the connections between preamp and the rest of the amp, and sever the ones I don't need. I've done almost all of that, but there are a few connections that I am unfamiliar with.
   -The first is a 3 wire connection between preamp and poweramp pcb's (3 pin clip on the poweramp end that separates into 1 red, 1 blue, and 1 black wire going to different places near eachother on the preamp end). This is separate from the preamp's line out that goes into the power amp- I know that is elsewhere. On the power amp pcb, the connection is labeled "CN2," and on the preamp side it's labeled "P101"(red), "P102"(black), and "P103"(blue).
   -I also am unsure which connections coming from the power transformer are which. There is a two pin (2 wire) clip that I'm assuming is kind of the "main power" right in the corner of the control pcb of the preamp, connected via the same clip on the transformer (labeled "CN1"). There is also one red wire going from transformer to preamp labeled "QC15" and "+15V" on the transformer pcb, and "P104" on the preamp pcb. (It's close to "P101-103" from earlier). There is also a black wire going from what seems to be the bottom of one of the huge capacitors (the size of a D battery) in the transformer section to somewhere underneath the preamp pcb. I haven't unfastened the preamp and taken it out of the chassis yet to see exactly where it connects.

If someone could let me know what these connects could be, I'd be very appreciative. Also, If you have any ideas on how to power this preamp once I've gotten it away from the poweramp and transformer, I could use that advice. I'm hoping it's as simple as figuring out how much juice it needs, and finding an AC adapter to patch in. Thanks in advance!