Tim -
Thanks. R3 in the power supply is 100 ohms, but I believe you're right.
In this case, I'd immediately suspect C4b, but that would not cause
smoke out of the transmitter.....
I'm still going with a shorted 6JB6.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs
<www.k4oah.com>
Bolbach, Timothy wrote:
I think he is referring to R3 in the power supply.
-----Original Message-----
From: drakelist-boun...@zerobeat.net [mailto:drakelist-boun...@zerobeat.net] On
Behalf Of Garey Barrell
Sent: Thursday, February 04, 2010 1:04 PM
To: drakelist@zerobeat.net
Subject: Re: [Drakelist] T4XB No +250V AND blown Filament Fuse
Paul -
I just got a chance to look at the T-4XB schematic. R3 is NOT a 1k 5W
resistor, at least on my schematics!
Where is this resistor in your unit? Physically and on the schematic.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs
<www.k4oah.com>
Paul Gerhardt wrote:
Turned on my Working T4Xb and smoke came out the bottom of the rig
which I can't see for some reason. The filimant fuse (8A pigtail lead
fuse near the 3 big power resistors) is open so replaced that, then no
250 V B+ and found R3 1K 5 watt resistor to be open. Both of these
were 'effect' and not cause (I suspect). I changed R3 and got 150V
and R3 is hot. Unhooked the yellow 250V wire to the rig and V is good
about 270V. Turned power OFF and measured Resistance on yellow wire
and it is low only about 150 ohms. Last thing is always suspect and
for this the last thing I did a few days ago was install some used
FleaBay finals which worked ok it seemed but were very weak only about
60-70 watts out (maybe one was not working?) Put the bright light on
the bottom and compared to photo I took before and fail to 'see' any
burned parts on the bottom but there was smoke and I think it was from
a hot wire and not a componet. Will probably change the finals back
to the 'other' weak ones that were at least putting out 120W into the
Cantenna and see what is pulling the 250V B+ line down.
Any ideas on this one?
73
Paul
some new pix on the port op for the 160M CQ CW contest last weekend on
www.pgerhardt.blogspot.com<http://www.pgerhardt.blogspot.com/>
--
Paul Gerhardt
K3PG
http://pgerhardt.blogspot.com
QRP ARCI 6674
FP 274
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