Premier Rock Forum

I'm trying to rebuild a power supply, and from what I can tell, some sort of power pump took out a few caps and the protection diodes around them (lots of black marks on the PCB). I don't have a schematic (it's a Soundcraft Protracker, and soundcraft declined to let me see it), and so I'm just going by component marking. I have a diode marked "LZ 51" but I can't seem to find a listing for it on mouser. It does look like these diodes made the ultimate sacrifice, even if a few caps went with them.


I also want to replace the transitors in the pathway, which appear to be a k1548 and a C1685, but am also have issue finding parts (can I just use a standard TO-220 for the 1548?). It looks like the k1548 and C1685 are on ebay, and are pricey. Also, these parts are not directly in the burnt area, but kind of figured I would just replace them to be sure.

Any help would be appreciated- I'm decent at some of this stuff, but some of these older parts are getting a little above my head.

lz51 might be zener--look at other soundcraft desk supply schematics--they are likely to be similar

don't know k1548 c1685; either regulators or pass transistors--look up datasheets to get a clue

do you have a meter with diode test function? do you need re-cap?

LZ51 might be a date code, not a part designator.

K1458 is probably 2SK1458 and C1685 is probably 2SC1685.

TO-220 is not a transistor type, it's a standard physical package type used by a wide variety of transistors, MOSFETs, regulators, etc.. Pinouts might be different, and parameters will almost certainly be different. There's an art to transistor substitutions that takes some time to find something that will work and not burn up immediately. It's likely that you can find a run-of-the-mill TIPxx series part that will work though.