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-   -   PPI A200 wont power up (http://www.diyaudio.com/forums/car-audio/204075-ppi-a200-wont-power-up.html)

Dr Zeus 9th January 2012 12:29 AM

PPI A200 wont power up
 
I've got this and a working A600.2 if its worth referencing parts for fixing this A200. This amp will now power up on the bench. No LEDs, no drive voltage to the fets. Non of the fets nor outputs are shorted. All outputs are measuring exactly 47 ohms across legs 1&3. It has a SG3525A:

SG3525A
Pin 1: 0.287
Pin 2: 2.568
Pin 3: 0.023
Pin 4: 0.338
Pin 5: 2.058
Pin 6: 3.631
Pin 7: 2.047
Pin 8: 0.005
Pin 9: 5.98
Pin 10: 0.001
Pin 11: 0.009
Pin 12: 0.001
Pin 13: 13.21
Pin 14: 0.010
Pin 15: 13.21
Pin 16: 5.16

1moreamp 9th January 2012 12:41 AM

how about the voltage on the fets leads ? what do they read ?

Dr Zeus 9th January 2012 12:52 AM

Fets are IRFZ44. This amp is 100% original never been worked on.

Leg 1: 0.009
Leg 2: 13.77 (+B ~0 ohms)
Leg 3: 0.001 (Ground ~0 ohms)

ivkata 9th January 2012 01:08 AM

u don't have any output of the SG3525A
so i think its replated no power

Dr Zeus 9th January 2012 01:25 AM

Are you thinking the sg3525a is defective?

ivkata 9th January 2012 01:35 AM

there should be an op amp as well near the sg3525a maybe u should check for power on it and output as well.In the past i had units fail to power due to bad op amp .Im newbie in this as well but hey 2 heads are better than one

Dr Zeus 9th January 2012 02:20 AM

Hmm this amp is different that what you are thinking, or a different rev. There are only 2 opamps in the whole amp and only in the audio section.

http://i886.photobucket.com/albums/a...108_221725.jpg
http://i886.photobucket.com/albums/a...108_221717.jpg

ivkata 9th January 2012 02:32 AM

how about the rp1 ic in the past i had orrion that failed to power due to the ic not getting power .have u tested transistors near the 3525a

Perry Babin 9th January 2012 03:02 AM

What's connected to pin 8? If nothing is connected to it, preventing it from going to 5v, I'd suggest replacing the IC.

If you short pin 8 to 5v (pin 16), does the IC produce output?

Dr Zeus 9th January 2012 03:40 AM

Pin 8 is connected to the 3rd leg of an MPSA06 at Q40.

Q40:
Leg 1: 0.001
Leg 2: 0.685
Leg 3: 0.005

Shorting Pin 8 & 16 only change Leg 3 of Q40 to 5vdc

Shorting Pin 8 to Pin 16 allows the amp to power up with regulated PS, but after about 10 seconds the amp flickers on/off with power and low-imp LEDs flickering. During <10 seconds regulated voltage look OK, but rail voltage drops from +-24v down to +-22v. Once it hits +-22v everything flickers.


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