Thanks Vic.
What has me scratching my head - why would it flash with no drive, just
idling, with the event triggered only by changing the T/R relay from
transmit to receive...?
(I suspect I am showing my ignorance).
Thanks - Mark N5OT
On 9/6/2024 12:01 PM, Victor Rosenthal wrote:
Just guessing, but you may have had a plate-grid flashover, which blew
the plate meter and then damaged something in the grid/biasing circuit.
Zener or capacitor perhaps?
Victor 4X6GP
On Fri, Sep 6, 2024, 15:49 Mark - N5OT <r-emails@n5ot.com
<mailto:r-emails@n5ot.com>> wrote:
Greetings.
Today I have a 2K-2 that has developed a problem. For grins / out of
curiosity, I thought I would see what I could get out of a pair of used
Eimac Y-826s that had tested good some years ago. After I tested
them I
wrapped those tubes up and put them on the shelf waiting for the right
moment.
The amp ran fine for maybe 2 hours on CW at probably 25-50% duty cycle.
I was surprised how much drive was needed - really the tubes performed
no better than the 3-400Zs I took out and set to the side. Oh well.
When I was doing some additional testing the following happened:
1. The little red breaker popped when I let up on the footswitch.
So it
happened during a non-key-down moment. I let up on the footswitch,
heard the click, amp now did not transmit. Checked breaker - it was
popped so I reset it. Amp now worked again but plate current meter no
longer works. Yes, I know I should have protected it. I am
assuming it
was not protected. Oh well.
2. Amp transmits just as it did, however, now the tubes glow orange
100%
of the time, even while idling at key-up.
I am assuming this is not a sustainable condition, something changed or
broke, and I need to not run it like this.
I am also assuming there are multiple smart guys reading this who know
from the description above what has happened and can guide me toward
restoring the amp to operation.
Learning by experience,
73 - Mark N5OT
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