"no name", not Hitachi ,2Sk1058 failed in low power practise use. Securing
screw to h/s was fine . Known problem of Randall using suspect devices?
probably 2006 PbF/RoHS labels

"Nutcase Kook "

"no name", not Hitachi ,2Sk1058


** Only Hitachi or Renesas make them.

Sometimes logos are omitted from the packs.


failed in low power practise use.

** How the **** would you know that ?

FFS - report customer stories as STORIES !!

What is the nature of the failure?

Why do you EDIT all the facts out of your bull**** posts.


.... Phil

More evidence of dodgey sourcing. The mounting hole is visibly off-centre
relative to the hole in the flange, displaced vertically.
Looking under x30 one of the 3 injection casting vent holes has this "ident"
impressed in the 1.3mm diameter recess
MALAYSIA
AG
8
also a presumed date code of 6F1 marked under the K1058 for th earchives,
but no maker name or logo
This was D-S short failure

Off centre hole is 0.3mm displaced vertically. No first rank manufacturer
would have that amount of engineering departure from the industry TOP3
dimensions

"Nutcase Kook"

Off centre hole is 0.3mm displaced vertically. No first rank manufacturer
would have that amount of engineering departure from the industry TOP3
dimensions


** Think you at clutching at straws instead of getting the amp fixed.

That FET has been working fine in the amp for many years - so it is not
likely to be a fake or dud.


...... Phil

I could not read the device number on the only other transistor on the pa
board. Required my PTFE magic trick to read it. Will add a bit of heatsink
to this TO220 .
TR7 on overlay
marked
TRF820
TR 542P
7D
and 83 impressed in the casting vent hole plastic
again no logo or makers name
no data found in wwwland
"passing off " as IRF820 ?
its not a bipolar transistor, the T of TRF is about the only readable letter
without PTFE, so not an I.

"Nutcase Kook"

I could not read the device number on the only other transistor on the pa
board. Required my PTFE magic trick to read it. Will add a bit of heatsink
to this TO220 .
TR7 on overlay
marked
TRF820
TR 542P
7D
and 83 impressed in the casting vent hole plastic
again no logo or makers name
no data found in wwwland
"passing off " as IRF820 ?
its not a bipolar transistor, the T of TRF is about the only readable
letter
without PTFE, so not an I.


** FFS - the full schematic is easy to find:

http://music-electronics-forum.com/t16660/

Click on the thumb size schem at the bottom of the first post.


..... Phil

Back working again replacing the TRF820 and 2SK1058 principally. I would not
have expected to see just 1Kohm separating the gate of an FET from the
anode of a valve.