Before messing seriously with the motherboard, I would pull all the cards
and clean the Molex pins with DeOxit.
- Jerry, KF6VB
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On 2025-04-03 10:44, Bill NZ0T via groups.io wrote:
I'm back again with the TR7. I put it away because I was frustrated
and have spent some time since bring a Heathkit SB-102 back to life.
That went well and now I'm ready to tackle the TR& again.
I spent the morning taking every plugin board out including the
display board and the boards underneath it. Then the tedious task of
taking the LPF module out as that's where I think most of the issues
are. I took LOTS of photos of all the wire connections so hopefully
once it's time to put it back I'll get those soldered correctly. To
refresh the issues here is what WB4HFN told me after he looked at the
rig and told me it is not repairable:
1. PA finals are bad.
2. Mother board is bad.
3. LPF assembly is bad.
When I asked for details I was told:
1. The TR7 was putting out full power on the lower bands, on the upper
bands the final went into oscillation.
2. The oscillator would not come on frequency because of a bad
crystal.
3. T he LP filter had a broken rotor switch.
4. The mother board is bad because when you push down on the board
some of the plugin boards stop working.
When I sent him the rig TX and RX were working but the ALC was not.
There was also an issue with not being able to get the 8.05 oscillator
to 5.645 mHz after trying various capacitor values for C1029 on the
PBT/Ref board and adjusting C1030.
So my plan is to thoroughly check out the LPF module (neither of the
rotors is broken) for anything bad then check that the wiring from the
module is correct and OK. Then thoroughly check out the mother board
for any issues. Any other ideas as to what to check out are greatly
appreciated!
73, Bill NZ0T
Links:
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[1] /g/DRAKE-RADIO/message/84103
[2] /mt/104249254/243852
[3] /g/DRAKE-RADIO/post
[4] /g/DRAKE-RADIO/editsub/243852
[5] /g/DRAKE-RADIO/leave/12260778/243852/767576506/xyzzy
