I have this amp for repair. Changed a lot of caps, because of leaking. On one side I have +29,5Vdc, and 28Vdc.
On the other two channels I have 37v and 20v..the input on the power supply transistors are equal. Also the input of the rectifiers are equal. I removed nearly all parts, still the same.
The amp draws in this star 1.3 amps. Goes straight in protect. So I removed a diode, to keep the ps on.
On the other two channels I have 37v and 20v..the input on the power supply transistors are equal. Also the input of the rectifiers are equal. I removed nearly all parts, still the same.
The amp draws in this star 1.3 amps. Goes straight in protect. So I removed a diode, to keep the ps on.
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Are you using the secondary center tap as the reference from the transformer producing the voltage for the other 2 channels?
If I use the secondary on one Trafo, this side is equal. If I test the same on the other side, then the before good side is not equal anymore.
So, ok. If I use the center for each Trafo, the rail is OK.. But still looking for the problem. All parts are OK. Removed all electrolyte and changed caps.
The Amp doesn't came out of protect. I hadn't any dc at the outputs.. Anyway removed all output stages... Changed a lot of caps.. Still in protect.
It's like on the photo. I removed now Stk350 000,because it got a little warm, and the other stay cold.
It's possible that the partially populated circuit is causing the problem.
What model?
Do you have a diagram?
Which diode did you remove to get it out of protect?
What model?
Do you have a diagram?
Which diode did you remove to get it out of protect?
I don't know the exact model. There are some diagrams for smaller amps, I have to check, if they are similar. I removed the diode from the tl598cn to get the ps working.
I don't think Mac amps have protection per se, if the lamp is on you're probably seeing the power guard circuit activated. From your description it sounds like you have a bad STK, they often fail because they do not have a heat sink attached so they overheat. I was able to locate replacements on ebay, they are not produced anymore so you'll only find chinese ones.
Hello, it should be a MC431 4Channel Amp.
I expect also the STK, because one get warm, the other stay cold. I go now, to reassemble the output.
One more question, beside the on terminal is another called pg...for what is that terminal?
And is there a circuit diagram, so that i can check additional the protection circuit?
I expect also the STK, because one get warm, the other stay cold. I go now, to reassemble the output.
One more question, beside the on terminal is another called pg...for what is that terminal?
And is there a circuit diagram, so that i can check additional the protection circuit?
So, everything is back in the amp, except one stk.. Is there a possibility to check this modules? Can I deactivate the power guard, to check the rest of the amp?