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Author Topic: Drake TR7 1 meg jump instead of 500kc  (Read 1423 times)
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Detroit47
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« on: October 01, 2021, 02:02:48 PM »

My TR7 has been running quite nicely for years. It has now decided to only jump 1 meg at a time when I push the up or down button. It is supposed to jump 500 kc this makes me loose half the 40 meter band and the same on ten and 20. I am at a loss as to where to start. It did this one other time and I shut it off and waited a minute and all was well. That didn't do it this time. I know there are Drake gurus out there please help.

Thanks Johnathan N8QPC
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W1ITT
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« Reply #1 on: October 01, 2021, 06:26:50 PM »

Periodically, it's good practice to open up the TR7, take the inside cover off and wiggle everything.  In particular, pull the boards out of the motherboard and replace them two or three times to wipe the contacts.  I have used just a bit of DeOxit on my fingertip on the card edge connectors.  This procedure has fixed mine more than once,  Also, the pushbutton switch contacts are suspect.  My late serial TR7 started needing the "treatment" about 20 years ago.  It's still a nice rig and I like the receiver in it but all the connectors eventually need some exercise.   If you look at the top of the cards you'll see a pair of holes about three inches apart to use with the card puller tool and if you don't have one you can fashion one with coat hanger wire and needle nose pliers.
Do the easy stuff first and it may well save you from getting into the logic circuitry.  If you have to, the good news is that most of the semiconductors are still available as most were standard items, not custom proprietary secret things.  I occasionally see the pushbutton switch banks on ebay but their owners seem to think there's gold in them.  I hope it doesn't come to that.
73 de Norm W1ITT
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Patrick J. / KD5OEI
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« Reply #2 on: October 01, 2021, 08:58:57 PM »

Its good to fire up things every 6 months or so and run all the controls a bit. I was told that in it's important to bring to full operating warmth for a few hours to help drive humidity from the RF coils. This applied to the R390 type stuff but it makes a lot of sense. A few times, I have had to put aside my hobby for several months at a time, resulting in some gear not being powered up for a couple of years. And then there were issues. Scopes dead, radios not working, etc.
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