Replacing the circuit board on a 931 2nd gen

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SpaceLobster

Member (SA)
Jan 13, 2012
488
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Uppsala, Sweden
Hey,

I've got a very annoying problem.
I got a 931 from America more than a year ago. It arrived and all but the circuit board had broken loose inside. It worked on one channel however, so I was kinda pleased. I read some threads and attempted to fix the problem with some deoxit in the headphone jack and working it in/out lots of times. Indeed there was sometimes stereo but for a few seconds, then it died.. So it was not really working at all and I decided to find a new circuit board. I did, for a reasonable price and I set about replacing it. Problem is, it's not really the same.. Some wires that connected to the original one I can't find a place for on the new one :bang: .. Also some wires have 3 or four heads but there are only two spots on the circuit board..I'm a beginner at this so could somebody tell me how they usually do it? I got it to power up with the new board and the speakers makes white noise, but I'd like to get at least AUX in working so I can listen to music in stereo.. Cassette is not my main concern. Radio would be nice tho.

So here are some pics:
DSCF4084.JPG
After unpacking

DSCF4349.JPG
original mono circuit board

DSCF4659.JPG
New circuit board with old wires marked

I have LOTS of pictures of the way it was setup on the old one, but a few wires just don't have a place on the new one ??
I looked at pics here and found some that looked like mine, but it's really hard to tell..

Peace
 

SpaceLobster

Member (SA)
Jan 13, 2012
488
1
18
32
Uppsala, Sweden
Don't know what to do about this.. Just tried pretty much all possible positions of the wires and still nothing. Might just switch back to the old circuit board and hope for mono..
Anyone done this before ?

Peace
 

baddboybill

Member (SA)
Jul 14, 2009
11,091
84
48
55
Hudson Florida
The problem with Lasonic is there are different parts that are absolutely not interchangeable. There for you need to find exact part for replacement. Each board has model on it so you should be able to match. This board has at least 3 different types used ;-)




Bad Boy Bill
 

Alberto

Member (SA)
Jan 3, 2013
565
0
16
Wallingford,Ct. USA
SpaceLobster said:
Hey,

I've got a very annoying problem.
I got a 931 from America more than a year ago. It arrived and all but the circuit board had broken loose inside. It worked on one channel however, so I was kinda pleased. I read some threads and attempted to fix the problem with some deoxit in the headphone jack and working it in/out lots of times. Indeed there was sometimes stereo but for a few seconds, then it died.. So it was not really working at all and I decided to find a new circuit board. I did, for a reasonable price and I set about replacing it. Problem is, it's not really the same.. Some wires that connected to the original one I can't find a place for on the new one :bang: .. Also some wires have 3 or four heads but there are only two spots on the circuit board..I'm a beginner at this so could somebody tell me how they usually do it? I got it to power up with the new board and the speakers makes white noise, but I'd like to get at least AUX in working so I can listen to music in stereo.. Cassette is not my main concern. Radio would be nice tho.

So here are some pics:
DSCF4084.JPG
After unpacking

DSCF4349.JPG
original mono circuit board

DSCF4659.JPG
New circuit board with old wires marked

I have LOTS of pictures of the way it was setup on the old one, but a few wires just don't have a place on the new one ??
I looked at pics here and found some that looked like mine, but it's really hard to tell..

Peace
Check the solder points of that center amp. It looks like it might of gotten hit because it looks tilted in pic. If pic is of the old original board that might just been the problem.
 
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