CD laser KSS-210A - Nad 5440 CD player

[doobydoo]

Thanks Mooly for that and suggesting looking at the pcb; I was ready to give up! There are 2 of these transistors for the FOD signal and the multimeter suggests they're fried when compared to other similar transistors elsewhere on the pcb. One perhaps overheated which killed the other as the scorch mark is just under one of them. Anyway I will replace and see what happens. In the meantime have a good Xmas everyone 🙂

 

[Mooly]

Yes, have a good Christmas 🙂

(if you suspect the transistors are faulty then the next step is to test them out of circuit)

 

[doobydoo]

Hello again,

My CD unit works fine since replacing the transistors. I found a link to the same problem.

NAD 5000 Monitor Series CD Player...I have a question | Audiokarma Home Audio Stereo Discussion Forums

"There is a common problem in these players with the focus coil drive
transistors Q102 and Q103. The original devices are physically very
small and can't dissipate heat well enough. The service note I have
suggests replacing Q102 with a 2SD669 or similar and Q103 with a 2SB649
or similar. The choice of transistor is not super critical, but I'd use
a complimentary pair, and the ones I've mentioned are not expensive. As
I recall there are some occasions when the other pair of drives right
near by (Q104/105?) have the same problem. Also look over the soldering
in this area while you have the board out."

There are 4 pairs of transistors which drive the lens focusing, spindle motor, sled motor and tray motor. Some suggest adding heatsinks.

All the best!

D.

 

[Mooly]

Thanks for the update Pleased to hear that you got it sorted.

 

[KONNZ]

Hello again,

My CD unit works fine since replacing the transistors. I found a link to the same problem.

NAD 5000 Monitor Series CD Player...I have a question | Audiokarma Home Audio Stereo Discussion Forums

"There is a common problem in these players with the focus coil drive
transistors Q102 and Q103. The original devices are physically very
small and can't dissipate heat well enough. The service note I have
suggests replacing Q102 with a 2SD669 or similar and Q103 with a 2SB649
or similar. The choice of transistor is not super critical, but I'd use
a complimentary pair, and the ones I've mentioned are not expensive. As
I recall there are some occasions when the other pair of drives right
near by (Q104/105?) have the same problem. Also look over the soldering
in this area while you have the board out."

There are 4 pairs of transistors which drive the lens focusing, spindle motor, sled motor and tray motor. Some suggest adding heatsinks.

All the best!

D.

Hi there - this looks like an old post - but I have the same problem - Did you replace 2SB1237 and 2SD1858 with BD131 and BD132 transistors?

Hopefully you can respond - Cheers

 

[Mooly]

doobydoo's profile shows he hasn't visited the site in over 5 years...

BD131/2 are generally fine for the kind of applications you are talking about.

 

[KONNZ]

Thanks for the reply - it was a shot in the dark.

I can't find BD131/2 but I can get BD139/40… would that do the job?

Cheers

 

[Mooly]

I would think so. The BD139/140 are higher voltage rating but that doesn't matter here. These are very non critical applications when used as output stages for motors and actuators.

 

[oggioffshore]

Old thread.
Still informative.
Tnx.

I'll have to check those trannies in my 5000 player as well.

 

[androa76]

I have problem with Kss150-210 laser in Denon dcd1460. After inserting disk, lens go up an down, disk not rotate, just move a few degrees and no disc. I changed laser optic (removed safety blob) to another and problem is the same. Test run gives result Error 2 ...no FGS (focus gain signal) detected, Measuring current on driver transistor shows voltage drop of around 1,4v on 22r ,so around 65ma current sucks the laser. Voltage on Laserled suply jump to 2v after play. No eye pattern is vissible on test pins. I cleaned laser start position switch.
I am confused that new laser is damaged because it shows same symptoms. Any help where to continue?
Thank you.