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Odd Luxman part

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dgta

Active Member
Guys, I'm rebuilding a Luxman R1120 and I'm having trouble identifying an unusual part.

The power amp has a biasing diode called out as KB-265. This is the "industry" part number, NOT the Luxman part no. There is a separate Luxman part no, TV0004. It's shown on the schematic as a double diode, but I suspect it's some type of thermistor diode.
The actual part is very small and more spherical then cylindrical in shape.

Can't find any reference to this part, what it is or cross reference. Anyone have any idea?
 
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Thanks Larry. That data sheet is in Japanese, which I don't read, but it does seem to indicate a diode with a thermal characteristic.

Unfortunately there aren't any sources for it that I can find. Does anyone have a source for obsolete semiconductors? Or a cross-reference to non-obsolete parts?
 
Could you elaborate on what you mean by "rebuilding"? Not just a regular old recap, I take it? Sure sounds interesting. :)
 
By rebuilding I mean that I am indeed recaping it plus one channel of the power amp was shot so I am replacing almost all semiconductors on the power board. I may do a few other tweaks while I have it open, still looking around to see what else may need improvement.

Interestingly enough, a whole power amp channel was burned out without blowing a single fuse (yes the fuses are all the right values) so perhaps additional protection/stability measures are in order :)
 
KB-265 biasing diode

pakko said:
A common replace is a 1N4002. Will work fine.
Click to expand...

dkintana said:
I replaced it with two BAV21 in series and it worked like a charm.
Click to expand...

I also have to replace two of these, maybe with ER204's? :scratch2:

vdiasg.jpg


2hp6mfd.jpg
 
I found several of these too in my Luxman SQ700X amp, can anybody confirm the 1N4002 sub will work?
 
It appears to be a standard double diode. Two 1N4148 in series should work just fine.
It is not the type of diode that can be mounted to a heatsink, so any thermal characteristics the original may have, appear to be irrelevant in this application.
 
Luxman KB-265 biasing diode

Alienz said:
Still waiting for confirmation on what will work from someone who did replace them too :)
Click to expand...
Seems that, if they are in the power board, then two 1N4148 in series are the best candidate for the KB-265 replacement. :)
But it's good idea use a bulb tester with bias trimmers turned down first... :thmbsp:

In other parts, one 1N4002 is fine.
 
Karl vd Berg said:
Seems that, if they are in the power board, then two 1N4148 in series are the best candidate for the KB-265 replacement. :)
But it's good idea use a bulb tester with bias trimmers turned down first... :thmbsp:

In other parts, one 1N4002 is fine.
Click to expand...

Thanks for explaining :)
I think mine are in the powerboard, not sure if i should replace them at all, havent tested them yet, amp is working fine, just needs a recap. Its just nice to know there are possible replacements in case anything does go wrong with these unobtanium diodes.
 
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