TRAM D201 2nd gen S-4 wiring

[ira parker]

Here's what I have Pin 1 anode of d128 to top lug clarifier. Pin 2- 3 blue/white , Pin 3 violet to anode of d125, pin 4-X, Pin 5-3 red/white, Pin 6-2 orange/white, Pin 7 Blank, Pin 8-X, Pin 9 Blank, Pin 10 orange, Pin 11 yellow, Pin 12-X. Everything is seems to be wired correctly radio functions. The reason I'm asking is PO put a double pole double throw switch on the back to get transmit on the VFO. One side of the switch is in series with red/white wire and pin 12 on syn board (easy enough fix) the other side of the switch goes to S-4 and ground at T-500. I would like to remove this mod and do it the way Chris @ Nomad radio does it without the extra switch. I have gone over everything in his post traced all the wires ect. none of the diodes have been changed it all seems to be factory configuration. My main question is the yellow wire he mentions in step number 10? The way its worded sounds like the yellow wire on Pin 11 should be on Pin 10? Any help would be greatly appreciated. Thanks Ira

 

[nomadradio]

I'll check my text file next time I'm at the shop. Don't have the ancient files at home, only on the air-gapped DOS machine at work. The yellow wire leads to the cathode of the VFO tube. Grounding it activates the VFO. Breaking that ground shuts it down for crystal mode. That wire remains on pin 11 of S4. The orange wire next to it on pin 10 gets rerouted to ground so the yellow wire will be grounded only in "Manual" mode. The orange wire is originally connected to a receive-side contact of the relay, so the VFO will shut down in transmit. Grounding the orange wire bypasses the relay.

73

 

[ira parker]

Thanks Nomad it's reassuring to hear it from the guru. I was pretty sure that's the way it should be when switching to manual just wanted to make sure PO hadn't moved it, reverse engineering some of these mods is more time consuming then it should be dotting the i's crossing the t's. Appreciate all the support I haven't done a lot of these old tubers learning as I go we'll see how much hair is left when I check the alignment out hopefully freqs will be close those old trimmers make me nervous. Once again thank you so much for sharing your knowledge on these I read and study as many of your write ups I can find. Thanks Ira