Precision Power P900.5 zobel problems

[Formas]

Good day guys, I’m currently working on this amp but the zobel network resistors are burn beyond recognition, anyone have a schematic or know the resistor values for it?
Also resistor R42E is unidentifiable (I get a 203ohms across the resistor in an incircuit test).

 

[Perry Babin]

Is the attached output section close? It's a Hertz HDP5. Others like Polk use it as well.

 

[Formas]

it’s the same design even with the legend, however is there any part change in resistor value due the fact of my network has C20A 474K/250V capacitor in series with R27A?

 

[Perry Babin]

I don't know. I know very little about these. I've seen a grand total of 1 of these and it was a Polk.

 

[Formas]

Based on your experience Mr Babin, what would be a likely problem or any negative or contributing factor if I make changes of the caps from 474K/250 to 105/(*250) with the series resistor 10ohms 2watts?

 

[Perry Babin]

Increasing the value of the capacitor will drive more current through the resistor and may make it heat up more, depending on the trash passing through the inductor and the high-frequency content of the music.

 

[Formas]

Are these caps any good to replace the ones I took from the amplifier? The amp is a full range amp, 4 channel out.

Is true that if the caps have no voltage identification, then it’s an 100v in maximum working voltage?

If those caps can be used, what would likely be the resistor value that I can use with them in that would be ok?

***Does the zobel network is the same as snubber network?

 

[Perry Babin]

100 v or maybe even 50v. Likely 100v for the green ones.

The type is very nearly identical. The casing is different. The function is essentially the same.

A Zobel helps stabilize an amplifier against inductive loads. A snubber damps spikes or ringing. I think this network is just to help clean up the output signal a bit. I don't know if it qualifies as either snubber or Zobel.

 

[Formas]

So likely the yellow caps (original) are 250v, can the 100v work in the amp (be advised that this amp isn’t for a customer, it’s used by the audio speaker dept. for testing speakers for sale for just a few moments at any given time).
Since the scenario is just momentarily, what value resistor could work?

 

[Perry Babin]

The 100v are likely OK but I have to recommend that you use the same rated caps, especially if you're charging for the repair.

Why on earth are they using such a complex amp for testing speakers? Any budget amp would do the job perfectly well.

 

[Formas]

What’s a likely value resistor I could use with the capacitors?

I think that amp was a store return, so it was eventually not sold as the 5th channel (dclass mono is giving out dc voltage) so they just use the full range sides to test..

 

[Perry Babin]

Why not use the values on the diagram? If used as you described, it won't really matter. They would likely only overheat if the amp was abused. You can let it idle and see how hot they run. If they run hot, you likely have a shorted inductor. I'm assuming that these are after the output inductor.