Fender p250 PA

[komatoast]

I can't find the wiring schematic online anywhere. Checked Fender.com first, and then tried various searches with no luck. The initial problem begin when a few of us were jamming and we had only a keyboard going through the p250 and after about 30 mins or so, it made a slight pop sound and then the power lite went off and the protect lite came on and stayed on. I've now got it apart and all circuits visible(after checking fuses, power outlet, cord, etc.)and i see nothing fryed in the circuitry. I was looking to find the schematic to check resistances before going out and dropping a load on another PA. If anyone here has ran across this and knows where a good place to start, outside of what I've done or anything to help with this beast of an electronic, it would be much appreciated.

[oc disorder]

Hi Komatoast and welcome to the forum.
Even the experienced techs like to avoid these if they can !
This sounds like a output stage fault or power supply.
If you haven't much experience the Passport is not a easy one to start on.
"Ooogle" found some schematics for me promptly.
Hope the fault finding is as quick !
Thanks to "archive at number26.org" I'll paste some links below.
One of them is probably the user guide.

http://schematics.number26.org/index...0Schematic.pdf

http://schematics.number26.org/index...Schematics.pdf

http://schematics.number26.org/index...port%20250.pdf

http://schematics.number26.org/index...port%20250.pdf

http://schematics.number26.org/index...t%20PD-250.pdf

[komatoast]

Thanks for the schematic links. I'll give them a shot as soon as i can make time to tear back into it. I'll let you know if I can conclude something. Thanks again!

[Enzo]

Oh, I didn;t recognize the model as a Passport at first...duh.

I find the largest pain in the as is just taking the damn things apart. Getting to the amplifier card. Once there, I have no problem fixing the amp. The power supplies do fail, but mainly they just shut down when the power amp dies. fender wants to replace the power supply as a unit, but I usually repair it.

But I don;t relish seeing them come in.

[jrfrond]

Typically, it is one of the power transistors that cooks in these things. They are 2SA1962 and 2SC5242. But I will tell you: the epithets will be flying when you go to disassemble it. NO ONE in our shop like to work on these, and even the cleanest of mouths seem to go foul when working on these.

[Enzo]

Exactly.

To free the rear panel, you have to remove the front panel. The cables to the front panel have not quite enough slack to let you move it freely, so you have to lift it part way, free some stuff then continue. Then get out the long blade driver to free the power supply, then pull the whole rear assembly out. Changing parts is then not so bad on the amp. of course connecting it for test is now a pain in the ass.

The mixer is pretty reliable, but working in the lower half of that panel is also real inconvenient.