Inphase IPA900 repair

[rrae]

Hello, amp is not powering up
TL494CN
1 0.6
2 2.7
3 0.05
4 0
5 1.45
6 3.31
7 0
8 11.80
9 4.60
10 4.60
11 11.80
12 11.80
13 4.87
14 4.87
15 4.87
16 0
Measured when on B+ 12V


If need - I can do macro img.

[rrae]

Found few leaking diodes, one near IC 16. leg, I will replace and post with updates.

[Perry Babin]

The power supply FETs are being driven. Do you have rail voltage on the center legs of the audio output transistors?

Place the black meter probe on one of the non-bridging speaker terminals. Place the red meter probe on the point where you need to measure the voltage.

[rrae]

Got 32.2V for all output transistors on center leg. No power/protection light on.

[Perry Babin]

Plus AND minus 32?

[rrae]

Not sure if I understand Your question right, black probe on non bridged minus terminal, plus probe on output tranzistors center leg, all reading +32,2V

[Perry Babin]

Half should read -32. Are you missing the -32v?

[rrae]

Sorry, yes, there is -32V for PNP tranzistors.

[rrae]

It's working! Thanks.

[rrae]

Got problems with this amp again. On ouputs was hooked blown subwoofer - like one ohm, protection lamp blinked and got turned off. Now in bridge it's burping and not playing clear audio, in non-bridge mode, it's playing audio, but not clearly and powerful as need - have noise. Where start to look first? No blown fuses.
Don't have scope, only DMM

Opamp section attached