True
We're NOT talking about a full alignment here. I merely suggested to
Joe that he check the RF and Driver trimmers to be sure they are at
least near peak.
Information gathered so far, over several days, indicates that there is
most likely an RF coupling problem in the Driver and/or PA. The DC
voltages on the Driver are good, and the PA idle current is good. It's
not yet clear if this is a multi-band problem or not.
This last bit of information says that the problem lies in either the
Driver or PA stages, and that the DC voltages are correct. This is the
first we have heard of the 'sizzle', which often indicates a very high
swr, causing 'something' to arc over from the very high peak voltages
generated. Possible problems include an RF choke with a shorted
turn(s), a capacitor that has broken down, or a simple flash-over from a
wire.
It seems that the most likely problem area is the coupling into and out
of the Driver stage. Again, the PA idle current is ok, just no drive.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-B, C-Line&
TR-4/C Service Supplement CDs
<www.k4oah.com>
Curt Nixon wrote:
GE Group:
Joe:
Just my 2 cents here...sudden failures of output are not caused by
alignment. It really sounds like a component failure of some sort.
The only thing messing with alignment will do for you at this point is
mask the solution to real problem.
You will get good advice here regarding sorting thru the possible
causes and isolating the fault. Don't mess with the alignment.
FWIW
Curt
KU8L
4 Line A and B, TR3 TR4 TR7 and much non-Drake classic equipment.
joe loverti wrote:
Garey,
I'm not sure I mentioned this to you or not. When I first realized I
was having this trouble with the low output on the TX I heard some
kind of a sound when I was tuning up. This was right at the onset of
the trouble. After hearing that sound is when I noticed my plate and
RF out was way low. Its been like this ever since I heard the sound.
I can't really accurately describe it other than a "flash" or a
"sizzle". Not sure if it was an arc or what. I don't see anything on
the variable capacitors that indicate that an arc occurred. I was not
using an amp at the time. Just tuning up barefoot into my DL and at a
fairly low power level. Could a component have failed?
I'm a little hesitant to attempt an alignment myself. I don't
consider myself much of a technician. I will read up on that
procedure some more before I give it a go.
Also, I am getting the exact same results whether I'm using the RCVR,
XMTR, or in separate to tune up.
73 and thanks!
-Joe
WS8X
_______________________________________________
Drakelist mailing list
[email protected]
http://mailman.zerobeat.net/mailman/listinfo/drakelist
