bhuskins
Super Member
I imagine it's made more difficult since 2SK78's are considering to be pretty much unobtanium.
Yes hopefully Patrice will be helping me out now that the problem has been fully diagnosed.
I imagine it's made more difficult since 2SK78's are considering to be pretty much unobtanium.
After reading up in the service manual it looks like it's the last 3 letters on the 3rd row that makes the difference...not sure what the middle row identifies.
2SK78
5Y05
AEL
2SK78
0411
AEL
So both being "A" and "EL" is what's supposed to matter...the "A" are specified for that location and "EL" is listed as an acceptable suffix.
Yes hopefully Patrice will be helping me out now that the problem has been fully diagnosed.
When you find good source of these transistors, I suggest to buy enough to replace all of them. Just keep them until you may need another swap. Also it will allow some kind of matching best pairs together.Small Update...
I decided to swap back just one of the 2SK78 to see if the issue would travel back to the other channel. This would determine if I need just (1) or (2) 2SK78 (A EL)
I swapped TR225 with TR226 and the problem went back to the Left Channel.
So, that's good news in that I only need (1) 2SK78 for the TR225/TR226 spot
The bad one was indeed the odd ball...
TR225
2SK78
5Y05
AEL
The other (3) good 2SK78 for TR226/TR221/TR222
2SK78
0411
AEL
Right high voltage Jfets could be a tough call. When I worked on my C-2x I found two sources for Jfets used there. One was NOS, another newly made ones. Though Jfets used there had more common parameters.Hello for_p1
When you find good source of these transistors, I suggest to buy enough to replace all of them.
don't you know that these VFET are no more availables since 30 years ?
I you have a good adresse let us know , we are many looking for it !