audiolab 8000a resistors

[dazsti]

hi everyone, ive done a search and come up with a few bits and bobs,but im a bit of a noob at diy audio so here goes-shorted my speakers -blown fuse in audiolab 8000a,replaced fuse- blows again,took lid of noticed 7 resistors burnt out,see pic-

An externally hosted image should be here but it was not working when we last tested it.

- so i took resistors out to look for colour codes, but the resistors are all burnt black like my wifes toast, so i ask does anybody know the values of the resistors marked in pic eg:R747=560 ohm???thankyou for any replies, if i cant fix it i will have to send it to the rubbish tip-nah only kidding- kev green at audiocellar !

 

[Bigred]

The best I can do is provide a schematic without the corresponding board numbers. You will have to follow the traces to some of the knowns from the schematic. A little more effort but works. The diodes and transistors are actually listed on the board as what they are D813=1N4002 for example.

EDIT: Come to think of it, the values of the resistors are what the number on the board is also. R743=looks to be 330ohm and R946=47ohm for example.

 

[rohms]

hi,
it is very clear that the part value of the component is listed on the board, resistor 47 ohms, diode and so on is already there on pcb.

 

[Bigred]

hi,
it is very clear that the part value of the component is listed on the board, resistor 47 ohms, diode and so on is already there on pcb.

Yes all but the ones that got blown off It was covered already

 

[tvi]

R743 330R
R747 47R
R935 470R?
R847 470R

another R847 ? 47R
D813 1N4002
R946 47R

The values are written on the board.
You can also compare one channel to the other.

Regards
Jaames

 

[dazsti]

LAST ONE ????

thanks for your replies,everyone-i get it now see revised pic-should have realized they were correct values on board -still leaves me with one unknown R935????-miniture atom bomb schorched the text and i cant read it!

An externally hosted image should be here but it was not working when we last tested it.

any help very much appriciated again thanks darren

 

[Bigred]

Thats why I told you that your going to have to follow the traces to some of the knowns and figure out the values from the schematic. It shouldn't be too difficult to map out.

 

[AndrewT]

Hi,
if the resistors are blown there could also be damage to the traces feeding those resistors.
There will definately be damaged transistors that caused the resistors to blow.
I wonder why the protection did not operate?
Sometime odd here.
Has the board been altered or the fuses changed for the wrong values or the wrong speakers attached or duff cables/duff fingers been poking around? Or something spilled inside?

BTW,
this is a stereo board, the good side should match the damaged side. Compare one to the other.

 

[richie00boy]

As Andrew said, change the output transistors and drivers, they will be partially damaged if not completely blown.

 

[Kajman]

I have finally fixed my audiolab 8000A without too much work in the end. I just had to be patient as the problem was not obvious. The protection circuit had fried components which i replaced. I still had not solved the problem as I was getting no output and the two 470R resistors in the protection circuit were heating up very badly. You will also notice that the relay does not click. The problem was still in the power amp section. All the transistors tested fine but just check for another short component on the side that fried the protection circuit. Mine is up and running and the cost was next to nothing as no transistor in the power amp needed replacing despite the protection circuit components being completely fried. Patience pays