Transistor burns out

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Mtz mohsin

Joined Dec 18, 2020
6
Anyone please help me I have an old a&d amplifier suddenly it stopped working when I open the cover and just saw this fuses were burned our I replaced them but when I turn plug in the fuses burns again and smoked come our of b600k transistor I replaced that transistor with another one which was not original but was close to this so when I replaced it burns again... can anyone help me. And sorry for the broken English
 

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drc_567

Joined Dec 29, 2008
1,110
... Sometimes if you list the brand and model number of the unit, someone on the forum can find the circuit diagram.
 

dl324

Joined Mar 30, 2015
12,871
Welcome to AAC!
I replaced them but when I turn plug in the fuses burns again and smoked come our of b600k transistor I replaced that transistor with another one which was not original but was close to this so when I replaced it burns again...
It sounds to me like you're just replacing components without addressing why they burned out in the first place; so they just burn out again.
 

Thread Starter

Mtz mohsin

Joined Dec 18, 2020
6
Welcome to AAC!
It sounds to me like you're just replacing components without addressing why they burned out in the first place; so they just burn out again.
Thanku for replying sir how could I address means what should be the reason behind this failure I just check few resisters that seems to be ok there were 3more transistors which were also burned out including this one I replaced them all they wouldn't burn out except this one.
 

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Thread Starter

Mtz mohsin

Joined Dec 18, 2020
6
The unit here was referenced as being the same as the A&D DA-U730.
Does it look to be similar?
A&D DA-U730 ?
Yes it looks somehow simpler in shape but internal parts are different today once again I was trying to fix the issue but failed again the transistor which I replaced with the original one again burn out I can't find the original transistor which is D600k Replacement transistor was B632K and which didn't work and then replaced tried another one which was C3117 both didn't work for me... Sir should you please tell me which transistor will be replacement for D600k and is the issue with transistor or there is problem with any element I also chage a zenor diode which was also faulty I checked resistors as well the all are fine but confusion is why the transistor burns? Can you please help me
 

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drc_567

Joined Dec 29, 2008
1,110
If you inspect the schematic diagram in the PDF listed above, is it possible to locate the defective transistor? There are several pages of circuit diagrams, with many labeled transistors. Locating the mystery transistor in the schematic diagram would likely provide a usable part number for replacement purposes, as well as explain the purpose of any adjacent components.
... Do you think the schematic diagram posted above is going to be like your unit?
 
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