Thanks!
The moral to the story here is this.
Problem/Issue/Symptom: Radio is low or no output, syntheseizer will only
settle down and lock up on two bands, and only after prolonged warmup. Start
TS at powersupply. 10v oka bit high at 10.4v. Upon close visual
inspection, found power supply transformer core top in two pieces on bottom of
rig. Started pulling boards. DR7 first, then power supply board.
Glued two top pieces together with super glue, then super glued the finished
top piece to the bottom piece on each side. VERY light application of super
glue with a toothpick. Also used a toothpick to shim up the bottom piece to
make contact while glue set. Now, no need for Drake hookup wire to hold top
piece on/in transformer. Top and bottom transformer cores now are together
instead of separated. Reassemble and test. Rig now works on receive properly
on all bands, but needs alignment. Adjustment of 10v and PBT controls
completed, receive is comparable to my Omni VI+ on all bands. Further
alignment will be needed since 10v is reset.
Note here, its tough to pull this board and work with it without bumping
the 10v pot, or the others as well. So any work on this area will likely
require a complete re-alignment of the radio. Hopefully not a serious one,
however.
Note 2: Seems as though the operation of the transformer is not real critical,
since super glue acts as an insulator. Plenty of flux lines remain around the
core for operation.
Note 3: Broke the rule: The only part of this TS that might be in error, is
that I pulled boards and cleaned contacts prior to testing (I figured that I
had the DR7 out, so might as well pull boards and deoxit contacts while I'm at
it). So I did more than one thing before testing. I broke the rule here, but
am reasonably sure the transformer issue was the sole cause of the synth lock
problem.
Other: Low output may be another issue to deal with. I'll be on that one, as
well as alignment, this weekend. I may have need of a better signal generator
if I cannot improvise, but we'll see. Need to figure a way to measure and
finely adjust output.
Well, gotta get an old Hammarlund and Swan off my bench (repaired) Sat AM first
thing!! Ah...the joy of tubes. One whale of a lot easier for me to deal
with!! Yep, sure is fun to resurect these old rigs.
Hope this info is a benefit to someone.
David
- Original Message -
From: Eric Webner
To: [EMAIL PROTECTED]
Sent: Friday, March 14, 2008 8:51 AM
Subject: Re: [drakelist] TR7 Project/Pwr Supplly Transformer
congrats! that always makes you feel good to finish a project like that.
73,
Eric KA8FAN
- Original Message
From: David Chris Drake [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Wednesday, March 12, 2008 10:32:35 PM
Subject: [drakelist] TR7 Project/Pwr Supplly Transformer
Just a note to all regarding the broken transformer core on the power supply
board of my project TR7. At first I figured I'd need a new transformer.
However, based on expert guidance from Ron and Bill, I was able to super glue
back the two broken top pieces and then simply glued the top and bottom halves
of the transformer together (my idea). I did leave the original Drake wire tie
for originallity, but it no longer serves any funtion.
That fixed the problem. The rig locks up on all bands just the way it should
and suprisingly its on freqency with only minor adjustment. All functions seem
to be working as they should on recieve. I'll be checking transmit tomorrow.
I know I bumped the 10v pot in process, but seems to be ok.
After checking xmit, I'll attempt full alignment and see where I end up. I
did repaint the top lid, as it was a later Drake black replacement and was
scratched up. I must say it looks very nice. Split rear panel, 5392, fully
loaded.
Thanks to all for their comments and offers of help.
David
Wd9cmd
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