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Randall RG100G3 powerFET amp
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N_Cook
May 19, 2011, 5:03:53 AM5/19/11
to
"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
screw to h/s was fine . Known problem of Randall using suspect devices?
probably 2006 PbF/RoHS labels
Phil Allison
May 20, 2011, 1:40:35 AM5/20/11
to
"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 fuck 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 bullshit posts.
... Phil
N_Cook
May 20, 2011, 3:14:19 AM5/20/11
to
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
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
N_Cook
May 21, 2011, 10:03:37 AM5/21/11
to
Off centre hole is 0.3mm displaced vertically. No first rank manufacturer
would have that amount of engineering departure from the industry TOP3
dimensions
would have that amount of engineering departure from the industry TOP3
dimensions
Phil Allison
May 21, 2011, 8:08:17 PM5/21/11
to
"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
N_Cook
May 22, 2011, 10:45:58 AM5/22/11
to
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.
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.
Phil Allison
May 22, 2011, 8:06:22 PM5/22/11
to
"Nutcase Kook"
** 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
N_Cook
May 23, 2011, 9:46:06 AM5/23/11
to
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.
have expected to see just 1Kohm separating the gate of an FET from the
anode of a valve.
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