KRELL 484081 and 484002 output transistors remplaces codes. HELP!!!

[fepablo]

HI, my name is Federico, from Argentina. I have a Krell KSA 100S Amplifier (year 1993). I remplace all capacitors and i find two output transistors broken. Are KRELL 484081 and 484002, do you have the motorola number to remplace.

Thank you

Federico Rodriguez.

[QSerraTico_Tico]

Originally posted by fepablo
HI, my name is Federico, from Argentina. I have a Krell KSA 100S Amplifier (year 1993). I remplace all capacitors and i find two output transistors broken. Are KRELL 484081 and 484002, do you have the motorola number to remplace.

Thank you

Federico Rodriguez.

Hello Frederico,
Here they are:
http://www.diyaudio.com/forums/showt...381#post493381
Unfortunately the parts are discontinued for the general public.
Perhaps with some creativity you can use the corresponding plastic case MJL types that are available.
Or the lower bandwith MJ21193 and MJ21194 in TO-3 metal package as your in your Krell.

[AndrewT]

Hi,
1993 KSA100s using 150W high speed output BJTs.
Is the 100s the same as KSA100mk2?

That never came up in the 100Klone thread!!
I was under the impression that these ClassA Krell's used MJ15003/4 as outputs. These 250W devices cope with the heat much better.

[fepablo]

Hi Guys, thanks for all.

There are a few photos od my Krell KSA 100s. Manufactured on 1993. Each channel have a 9 Krell 484081 and 9 Krell 484002, then each channel have 18 power transistors, 36 in all Krell. I have broken only two Krell 484081 on one channel. What I must to do? Only change those two? use MJ15003 or MJ21194 ? Or change all the transistors of the channel?









Thanks Again.

Federico Rodriguez.

[AVWERK]

You could get away replacing all with mj15024/15025 T0-3,s I would imagine.

Regards
David

[Chartal]

Originally posted by AndrewT

Is the 100s the same as KSA100mk2?

I think the 100S have the "sustained plateau bias"

[AndrewT]

Hi,
I think the two transistors out on their own are the drivers.
The other sixteen are an 8pair output stage.
I suspect that the 8 in each pair are matched.
If the drivers have gone then replace with individual transistors.

I cannot see how a singleton among an 8pair could fail and leave 7 working.
But if one of the 8 has failed then I think you must replace all 8 with a matched set.
Will Krell supply a matched set?
Or will they insist on $$$$$ for an approved repair.


Let's hope it's the drivers.
But, don't use a slow driver with fast outputs.

[fepablo]

The KRELL is WORKING!!!!!

I replace the 3 x Krell 484081 with 3x MJ15024 and the Krell 484002 with MJ15025. All transistors are from output stage. Krell sells the transistors orginal´s $15 each.
Also replaces all nichicon capacitors that are destroyed by siemens capacitors.

Thanks You.

Federico Rodriguez.

[AVWERK]

Told you so

[Leolabs]

Love the pics,fepablo!Show us more.