Crunch P1500.1

[S Merlington]

Anyone have a pic of the circuit board around the drivers in the output section of this amp?

Or know the value of C20?

 

[Perry Babin]

It appears to be the same as the attached board. If so, it's a 470pf.

 

[S Merlington]

Thank you for the info..

Can i replace it with a disk cap ?

 

[Perry Babin]

Yes. It's a ceramic cap (same as the disc capacitor).

 

[S Merlington]

Ok replaced the capacitor..

Amp powers up but no sound..

I have + - 15 volts on power supply pins of all op-amps..

I have both positive and negative rail voltages 55 volts

I get rail to rail oscillation

I get audio on all op amps

but still no output..

Any ideas?

 

[Perry Babin]

If you have rail-rail oscillation, there's a problem.

Was that capacitor removed by someone or did it appear to be left out by the manufacturer?

 

[S Merlington]

It was taken out by someone

 

[Perry Babin]

Are you sure that it's oscillating?

If so, remove the cap to see if it stops.

 

[S Merlington]

Ok i will have to get some resistors tommrow morning this amp just self distructed on me..

I will replace all resistor that smoked and post back when i get it completed

 

[ultra]

If you need any pics,i have an identical amp on my bench.

 

[S Merlington]

Perry,

In your pic that shows the board The transistors marked A1015 and C1815
are defective in this amp..

Is there a suitable replacement for theese?

 

[Perry Babin]

The KSA1220A and the KSC2690A would probably work. If you twist the base and collector on the MPSA06 and MPSA56, they would work.