Behringer pmp9xxx mixer amp Hi inputs not working + Ultratone info please.

[jbmdisco]

Behringer pmp960m
I had one of these brought in at the beginning of the week. Customer told me about a year ago one output stopped working but it was OK because he just plugged two speakers into the one channel. Fine. Anyway the amp was borrowed and returned with no output. It had been borrowed by a keyboard player who plugged his keys into the hi ins. Customer reckoned it would be the output chips.
Onto bench, plugged speaker into A + B, connected source (mic low z), powered up - perfect, all 6 channels! Thought it would be a return to customer with standard min charge. Sourced into Hi ins and nothing. I suspect that there will be one or more op-amps gone to silicon heaven. With the general lack of schems available and Behringer unwilling to assist is there any good souls able to point me in the right direction with this.

Behringer Ultratone 1800fx keyboard amp
I recently bought this for myself as a project for my own use.
The driver is blown which isn;t a problem.
The power amp was also in a sorry state with the board well beyond repair. I replaced this with a 200w 'kit' amp.
The problem I now face is that the power for the mixer section is integrated on the original poweramp board, well beyond redemption !!
What voltages are required to power the mixer/effects section of this amp? Again Behringer are of little help, directing me to their agents who want me to send them the amp for repair.

Festive greetings + thanks

[Jazz P Bass]

Those PMP960 amps are real treat to work on, huh?
NOT!

Typically, Behringer uses an e cap & a resistor to join the Line in to the Mic input.
Generic Behringer input scheme attached.

The 1800FX will need the high voltage rails hooked up as the low voltage + & - 15Vdc regulators are derived from it.
Also there is a 24 Vac winding that runs the fan but also powers the 5Vdc regulator.
Schematic attached.

And Festive Greetings to you, too.

[jbmdisco]

Thanks JPB for the info and the 'holy grail' of schems.

PMP amp - I retested this amp for a good couple of hours yesterday Hi-z's and Low-z's, aux in etc etc. I now believe that the amp-fairies have visited as absolutely no faults have re-curred or shown again. The owner has now collected the amp, and after a demonstration of it to him i have now become some sort of icon to him. Have never had anyone so happy at getting an amp back!
BTW I seem to remember something about Behringer never copying other manufacturers - I had this sat beside a Yamaha EMX 640 'box' mixer/amp - It's amazing how designers 1000's of miles away can come up with almost identical faceplates, down to folds and positioning. Need to let BHR know that Yam copied them (about 10 years before the idea was conceived )

1800FX - I have utillised an 18v transformer and made up a ps board giving +15v,-15v and +5v. After some further testing I will install it into the amp and give it a go. I did intend using a feed from the existing transformer but decided that it would be better to leave it solely to power the power-amp. My amp differs slightly from the schem as I cannot find a fan installed anywhere within the casing nor does it look like there has ever been one (no screw holes etc etc) But as I do have a 24v fan lying in the junk box I may utillise this for extra cooling on the amp - this may have prevented the stock amp from so dramatically burning out.