Luxman L-120a w blown transistors. Help needed.

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Jonas83

Member
2010-07-15 9:42 am
hi guys!

Got this Luxman L-120a with damaged transistors.
It is sanken C2581/A1106, seems to be quite hard to find? Out of stock etc.

Replacement? Any suggestions?. Found some sumitomo(!?) transistors but are they ok?
And..... How to bias this one? Changing the pots i will do.
 
Any of these will perform admirably:
2SC3263/2SA1294, 2SC3519(A)/2SA1386(A) from Sanken, and I would preferably use those amongst other things because of higher specs.
As alternatives which are often easyer to find, you might look at:
2SA1186/2SC2837, 2SA1941/2SC5198, 2SB817/2SD1047, these are closer to the original specs.
Do not forget to change the driver transistors and the bias generator (Vbe multiplier) transistor! They might seem OK and even be Ok but if there's anything wrong the output stage will fry again.
 

Jonas83

Member
2010-07-15 9:42 am
That helped me alot, thanks. placing an order on 3263/1294 asap. Will bring the beast down checking out the driver and generator transistor (the four w cooling sinks?) for model and throw in those new to.

I´am definetly no expert on this type of circuits, i think i need to figure out how this comes together in order to not fry it again = P. never seen a emitter resistor w 3 legs like that....
 
check ....

you may check yor local Yamaha dealer ..... they sell this in matched pairs made by sanken and in the best of quality .... of course ou will need to change the working ones also just for reasons of symmetry ... then again you will need to verify ofset and idle values

once more verify that all the resto of parts is working properly that will be fusible resistors and most imp[ortand all small electrolytic capacitors ....
 

donpipo

Member
2010-03-06 4:57 pm
Hello there!

Resurrecting an old thread and wanting to resurrect a Luxman M-120 sharing the same transistors.
I've faced the same problem and followed sakis' advice :)
I've found 4 pairs of 2SC3263/2SA1294 sourced from Yamaha replacements parts.

I forgot to check and I have two pairs in the O (50-100) hFE range and the two others in the Y (70-140) range.
I've nothing to measure reliably their hFE.

I think this is not an issue but just wondering where to distribute the Os and the Ys?
If this should be concern...

Thanks for your advices.

Alex.
 
Hello preludefan!

I think the pair 2sa2151 - 2SC6011 can easily replace the pair 2SA1106 - 2SC2581.
The case style and the pine connections are identical.

Regards!
 

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