Blow up once, Blow up twice and Blow up somemore

S.C · 4th March 2005, 10:54 AM

I blowed Caps, blowned diodes, and broke the copper on PCB. Finally, I blow up the LM3875.....

I finally got my 25V+25V PS fix.... it actrually come out to be 38.3-.7 +/-

Before I put the PS back together, I was using a stable 12V supply to run the amp section, No Problem.

Later I fixed the 25V+25V PS and connected to the Amp section, and the chip blow as soon as I turn on the power.

After the Chip blow, the PS still fine and getting the same reading.

Then I wonder can I connect PG+/- together from the amp section then out to a cable to the rectifer board? Because it is connect together in amp section anyway.

*********PG+ ---*****************-----PG-*************
Amp section******\ One Power cable /********Rectifer board
***************/-----------------\*******************
*********PG- ---*****************-----PG+*************

* = empty spaces

The problem is my amp section.... 3:45am... I need to sleep now. Continue tomorrow. Pictures tomorrow too.

revell · 4th March 2005, 06:04 PM

I blew some LM's too: in my case it was caused by switching V+ and V-.
As for the grounding issue: I would say keep PG+ and PG- separate. It was designed this way probably for a reason

jleaman · 4th March 2005, 08:31 PM

Pictures of the blown parts of pictures of the wiring setup ? both would help us help you..

J'

S.C · 4th March 2005, 11:18 PM

Left Channel Blown Chip

Left Channel Full View

Right Channel Blown Chip

Right Channel Full View

THE PROBLEM

The wire on the paper suppose to be V- but I put V+ there.....

I have a question. How come I use the a electric meter to test the connectitive. The meter beep when I connect everthing together while I put the niddle to V+ and V-? If I test The Power Supply allone, the meter won't beep. Is it the blown chip bridge or it is suppose to be like that? Also should I replace ever compounet or I just change the chip?

hifi · 4th March 2005, 11:50 PM

Tip of the day : If the wires carries different signals/voltages use different coluors!

jleaman · 4th March 2005, 11:54 PM

I cant really tell but it looks like that resister is in the wrong spot and looks to be shorting stuff out. got a better Picture. ?

thomas997 · 5th March 2005, 02:17 AM

Quote:

Originally posted by jleaman
I cant really tell but it looks like that resister is in the wrong spot and looks to be shorting stuff out. got a better Picture. ?

Yeah it looks as if it might be a cold solder as well?

Nice pictures though.

S.C · 5th March 2005, 03:25 AM

OK ! It is offical that I only mixed up V+ and V-. Now I changed the chip and switch the V+/V- back to normal. Now sounds is coming out. Thx guys !

tawen_mei · 5th March 2005, 07:57 AM

The meter beeps because capacitors are shorts for a while. If you leave the meter there long enough for the capacitor to charge up, the beeping would stop.

speaker · 5th March 2005, 04:04 PM

"Measure thrice, cut once!"

Having let the smoke out more than once over the years myself, I finally started triple-checking before I turned on the juice. Nothing like having a PS capacitor pop right in your face though. Smells like victory!

speaker

4th March 2005, 10:54 AM	#1
S.C diyAudio Member Join Date: Jun 2003 Location: Milpitas	Blow up once, Blow up twice and Blow up somemore I blowed Caps, blowned diodes, and broke the copper on PCB. Finally, I blow up the LM3875..... I finally got my 25V+25V PS fix.... it actrually come out to be 38.3-.7 +/- Before I put the PS back together, I was using a stable 12V supply to run the amp section, No Problem. Later I fixed the 25V+25V PS and connected to the Amp section, and the chip blow as soon as I turn on the power. After the Chip blow, the PS still fine and getting the same reading. Then I wonder can I connect PG+/- together from the amp section then out to a cable to the rectifer board? Because it is connect together in amp section anyway. *******PG+ ---*************-----PG-********* Amp section**\ One Power cable /****Rectifer board ***********/-----------------\*************** *****PG- ---*************-----PG+*********** * = empty spaces The problem is my amp section.... 3:45am... I need to sleep now. Continue tomorrow. Pictures tomorrow too.

5th March 2005, 04:04 PM	#10
speaker diyAudio Member Join Date: Mar 2004 Location: USA	Old curmudgeon carpenter sez....... "Measure thrice, cut once!" Having let the smoke out more than once over the years myself, I finally started triple-checking before I turned on the juice. Nothing like having a PS capacitor pop right in your face though. Smells like victory! speaker

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4th March 2005, 06:04 PM	#2
revell diyAudio Member Join Date: Jun 2004 Location: Kemzeke	I blew some LM's too: in my case it was caused by switching V+ and V-. As for the grounding issue: I would say keep PG+ and PG- separate. It was designed this way probably for a reason

4th March 2005, 08:31 PM	#3
jleaman Banned Join Date: Apr 2002	Pictures of the blown parts of pictures of the wiring setup ? both would help us help you.. J'

4th March 2005, 11:18 PM	#4
S.C diyAudio Member Join Date: Jun 2003 Location: Milpitas	Left Channel Blown Chip Left Channel Full View Right Channel Blown Chip Right Channel Full View THE PROBLEM The wire on the paper suppose to be V- but I put V+ there..... I have a question. How come I use the a electric meter to test the connectitive. The meter beep when I connect everthing together while I put the niddle to V+ and V-? If I test The Power Supply allone, the meter won't beep. Is it the blown chip bridge or it is suppose to be like that? Also should I replace ever compounet or I just change the chip?

4th March 2005, 11:50 PM	#5
hifi diyAudio Member Join Date: Mar 2001 Location: sweden	Tip of the day : If the wires carries different signals/voltages use different coluors!

4th March 2005, 11:54 PM	#6
jleaman Banned Join Date: Apr 2002	I cant really tell but it looks like that resister is in the wrong spot and looks to be shorting stuff out. got a better Picture. ?

5th March 2005, 03:25 AM	#8
S.C diyAudio Member Join Date: Jun 2003 Location: Milpitas	OK ! It is offical that I only mixed up V+ and V-. Now I changed the chip and switch the V+/V- back to normal. Now sounds is coming out. Thx guys !

5th March 2005, 07:57 AM	#9
tawen_mei diyAudio Member Join Date: Jan 2005 Location: California Republic	The meter beeps because capacitors are shorts for a while. If you leave the meter there long enough for the capacitor to charge up, the beeping would stop.

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