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Old 18th November 2012, 04:20 AM   #11
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Read the basic repair page (link in sig line below), paying special attention to the information in the yellow box. It will help prevent blowing new parts.

I don't have any information on this amp so I can't offer any specifics but the driver circuit may have been damaged. You need to test the driver circuit and its components before ordering or installing any new parts. Post a good quality photo of the board so we can see what you have.
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Old 18th November 2012, 04:32 AM   #12
Zaapp is offline Zaapp  United States
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this will answer all those... my answers to the bullet points

  • not under warranty
  • I want to learn
  • using a 10 amp fast acting breaker
  • didnt have to do this after replacing the FETs, powered up first few times with a 1 amp kenwood current limited power supply at work, never showed any trip faults or excessive current draw
  • never would I power it without doing such a thing first, I actually work on a lot of electronics at work, but none of them are as cool as a big power amplifier.
    not a ppi amp
  • check
  • check, all seems good
posting a "good quality" pic of the inside of this amp is going to be the killer part as the only camera I have is a dumb iPhone, but I will see what I can manage to get from it and post them here.

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Old 18th November 2012, 05:04 AM   #13
Zaapp is offline Zaapp  United States
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Best I can do for the moment, sorry if it's terrible, iPhones don't have the best camera
Click the image to open in full size.Click the image to open in full size.Click the image to open in full size.Click the image to open in full size.
this was the worst of the damaged FETs that were removed the first go around
Click the image to open in full size.
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Old 18th November 2012, 07:50 AM   #14
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At least post the photos at a larger size. Read the section of the repair page that deals with getting better photos.

You can't blow out all of those FETs with a 1 amp power supply. The amp isn't likely to power up properly with such a supply either.
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Old 18th November 2012, 08:24 AM   #15
luka is offline luka  Slovenia
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yea, i think you will need 5-10A supply
scope wouldn't hurt, but i don't think you will get one just for the amp

in most amps, there are only few things that will die, you will find all of them, i'm sure
just take it slow, step by step

btw, not the most easy amp to learn on
best of luck
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Old 18th November 2012, 02:55 PM   #16
Zaapp is offline Zaapp  United States
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I used every tip I could for getting those pics with an iphone 3g (the only camera I have) I will attempt to borrow one from someone, but I know very few people, and nobody close to home. may take me a day or two to procure.
Maybe they all blew the first time I connected it to the battery thru the 10 amp breaker... I really don't know.

sorry about the pics being small. heres the larger ones
Click the image to open in full size.Click the image to open in full size.Click the image to open in full size.Click the image to open in full size.Click the image to open in full size.

I have a single trace scope, albeit not a very good one but I do have one... a Midtronics EXP-1000...

Maybe I can get a better pic with my camera, now that it's daylight outside. I didn't have a great light source last night no matter what I tried, and those pics look very distorted after posting them here

Last edited by Zaapp; 18th November 2012 at 02:58 PM. Reason: added that I have an oscilloscope
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Old 18th November 2012, 03:08 PM   #17
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Those photos will be good enough for now.

The driver transistors are Q7, 8, 7A and 8A. The ones with an A prefix (A1275 possibly) are the ones that most commonly fail. After checking the drivers and replacing any that have failed, you'll need to remove the shorted FETs and look at the drive signal on the gate pads for the power supply FETs. Post a photo of the drive signal on the gate pad for the two FETs farthest away from each other on each side (4 photos).
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Old 18th November 2012, 03:22 PM   #18
Zaapp is offline Zaapp  United States
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q7 qnd q7a are C3228's and q8 and q8a are the a1275's

working on removing the spring clips now so I can test them (I have to remove those transistors to test them right?)
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Old 18th November 2012, 03:23 PM   #19
Zaapp is offline Zaapp  United States
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you must have a schematic for this amp? if so can I perhaps get a copy? I own 4 of these amps and it would be great to have for next time/later
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Old 18th November 2012, 04:14 PM   #20
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I don't have a diagram for this amp. It's has a lot in common with other amps. The power supply layout is a lot like the hifonics amps (and others). Email me and I'll send you a copy of a schematic diagram for an amp that uses a similar power supply circuit.

babin_perry@yahoo.com
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