Technics SU-8600 Transistor Guru needed

[andromediamn]

I have one dead channel on a Technics SU-8600, would the 2n3773/2n6609 pair be suitable replacements for the 2sd427/2sb557?
I have enough of the 2n types to do both channels.

 

[p4spooky]

May NOT be a suitable replacement. The Onsemi spec sheet does not list fT.
MJ21193G and MJ21194G will be a safe replacement from Mouser or Digikey.

Check this link for more information.

 

[sregor]

Ft is only min 3Mhz typical 5Mhz for 2sd427, so the 3773 should be okay. Referenced link from previous post - says post 1980 2n3773 should be around 4Mhz.
I agree MJ21193G and MJ21194G will be better...

 

[andromediamn]

Thank you both. It was the unknown ft that I wasn't sure about.
I noticed in the service manual they list the 2sd555/2sb600 for the higher voltages in oversea use.
I have a few pulls from a Nikko Alpha I amp I upgraded a while back, looks like I can use them (@120V), correct?

 

[zaibatsu]

You can use 2SD555/2SB600 if they are genuine originals and working, preferable to the 2Nxxxx parts.

I'd also add that in this amp the main capacitors are a disaster waiting to happen (if not already) and must be replaced, they physically leak and in extreme cases will eat holes right through the PCB and traces. There are some more suggestions specific to the SU-8600 in this thread, regarding the input stage and driver transistors, the latter which you will need to check (and possibly replace) given the output stage failure. Be sure to use a dim bulb tester for initial power up after repair.

 

[andromediamn]

You can use 2SD555/2SB600 if they are genuine originals and working, preferable to the 2Nxxxx parts.

I'd also add that in this amp the main capacitors are a disaster waiting to happen (if not already) and must be replaced, they physically leak and in extreme cases will eat holes right through the PCB and traces. There are some more suggestions specific to the SU-8600 in this thread, regarding the input stage and driver transistors, the latter which you will need to check (and possibly replace) given the output stage failure. Be sure to use a dim bulb tester for initial power up after repair.

The 2SD555/2SB600's are genuine, I'm the original owner of the Nikko amp and yanked them to upgrade to some MJs probably the 21193/94s, it's been a while since I did that one.
Thanks for the link, Ill be going over all the boards, and I live on the dim bulb.