Xtant X1001

S Merlington · 2013-03-09 7:34 pm

My friend came over with one of theese..

I removed all power supply fets since they were shorted..

I replaced all 4 of the A56's on the board also replaced the 10 ohm resistors..

Left the power supply fets out and hooked the amp up to look at the gate signal ..

With no power supply fets installed the amp burns all 4 of the A56's in it within 5 secs Any ideas?

Perry Babin · 2013-03-09 10:55 pm

Remove the PZTA56s and the 10 ohm resistors. Replace the 10 ohm resistors (R430/431?) with 1k resistors. Do you see a square wave on the base of the A56s?

S Merlington · 2013-03-09 11:51 pm

Do you want me to leave the 56's out and touch the bvase pad or replace the 56's then do the test after the 1k resistors are in?

Perry Babin · 2013-03-10 1:29 am

Leave the 56s out.

S Merlington · 2013-03-10 1:45 am

i see a squre wave but it doesnt look good at all

Perry Babin · 2013-03-10 3:35 am

You'll either have to post a photo or be MUCH more descriptive.

S Merlington · 2013-03-10 3:51 am

The square wave looks more like a triangle wave If need be ill post a pic

Perry Babin · 2013-03-10 4:21 am

Post a photo and include the scope settings.

S Merlington · 2013-03-11 10:59 am

Back to this amp..

As soon as my camera charges i will post a pic..

I get a nice square wave on pin 8 of the TL494 but the square wave is distorted on the Base of the A56's..

Dont know if this helps any

S Merlington · 2013-03-11 8:51 pm

Heres a pic of the square wave on the base of the 56's

Scope is set to 5us .5 volts div

Perry Babin · 2013-03-11 9:05 pm

Did you have the scope set as suggested in the 'best initial settings' section of the scope page (not including the settings you listed)?

S Merlington · 2013-03-11 9:19 pm

Yes and i get the same results as in the image

10us 5 volts div

Perry Babin · 2013-03-11 9:25 pm

Did you have the coupling set to DC?

S Merlington · 2013-03-11 9:30 pm

had it set to AC coupling

Perry Babin · 2013-03-11 10:31 pm

Please read that section again. Page 73 on the car audio site. Using standardized settings eliminates the need for me to ask half a dozen questions.

After setting the scope as suggested, post the waveform again.

Again, this needs to be done with the 10 ohm resistors and the four A56s out of the circuit.

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