Tram D201 VFO Mod

[mark4]

Waiting for the best way to open the VFO. (Need info for the late version)
2600 has some info I'm waiting for also. Hint hint.

[2600]

Finally found this file and got it converted from Wordstar to a plain text file.

Here goes nothing.

Clarifier/vfo modification for Tram D-201 23-channel base radio.

C.R. 1/25/96; 12/17/97 (step 8); 7/15/00 (STEP 12)



1)- REMOVE Q101 FROM THE SYNTHESIZER BOARD (THE ONE NEAREST THE
CENTER OF THE BOARD)

->DEFEATS HALF OF THE "9-12 CRYSTAL CUT-IN" THAT WAS USED IN
THE ORIGINAL FACTORY SET-UP TO KEEP THE SLIDER DIAL MARKINGS
CORRECT REGARDLESS OF THE CRYSTAL SELECTOR CHANNEL POSITION.

2)- MAKE SURE THAT D125 IS PROPERLY IN PLACE. D125 IS THE ONE
NEAREST THE BIAS TRIMPOTS. CUT D124 LOCATED UNDERSIDE JUST
BEHIND SQUELCH POT. CUT D126 ON THE REAR OF THE MODE SWITCH

-> REMOVES 14V FROM SYN BOARD PINS 11 AND 9 VIA S3, DISABLES
THE OTHER HALF OF THE "9-12 CRYSTAL CUT-IN". PINS 11 AND 9
FEED THE 16.4085 AND 16.4115 CRYSTALS (CHS 9-12) REGARDLESS
OF CHANNEL SWITCH POSITION. DIODES D114 AND D116 PREVENT
THIS FROM TURNING ON ANY OF THE OTHER 16 MHZ CRYSTALS.

3)- MAKE SURE THE YELLOW-WHITE WIRE FROM THE TOP (CW) OF THE
CLARIFIER POT TO THE SYN. BOARD IS IN PLACE.

-> THIS WIRE COMPLETES THE CLARIFIER POT CIRCUIT TO THE
FIXED RESISTORS ON THE SYN. BOARD.

4)- REMOVE THE * OTHER * YELLOW-WHITE WIRE AT THE TOP (CW) LUG OF
THE CLARIFIER, ADD SUFFICIENT LENGTH TO REACH S4-6.(ONE OR
TWO ORANGE-WHITE WIRES)

-> THE ORG-WHI WIRES ON S4-6 ARE CONSTANT 14 VOLTS, THE
YELLOW-WHITE WIRE LEADS TO THE MODE SWITCH AT S3D PIN 9, AND
CONTINUOUSLY SELECTS THE MAIN SET OF 16-MHZ XTAL SELECT
DIODES ON THE SYN.BOARD. THIS IS NECESSARY SINCE THE "CH 9-12
CUT-IN" DIODES HAVE NOW BEEN DISABLED BY CUTTING D124 IN STEP
2 ABOVE.

5)- MAKE SURE THE VIOLET WIRE (LEADING TO THE HOLE IN THE
CHASSIS UNDER S4) IS SOLDERED TO S4-3.


2




6)- Remove the three blue/white wires from s4-2, strip the ends
and solder all three ends together into a bundle.

7)- Remove the anode end of D128 from S4-1, solder to the 3-wire
blue/white bundle.

-> This supplies B+ to the clarifier during receive for both
manual and crystal modes.

.pa
8)-THERE ARE 2 (OR 3) RED/WHITE WIRES ON S4-5. ONE OF THEM GOES
TO PIN 12 ON THE SYN.BOARD. LEAVE THIS ONE ALONE. ONE (OR THE
ONLY) OTHER RED/WHITE WIRE GOES INTO A HOLE IN THE CHASSIS. MOVE
THIS WIRE FROM S4-5 TO S4-2. IF THERE IS A THIRD RED/WHITE WIRE,
IT GOES TO THE 'CAL' SWITCH. LEAVE THIS ONE ALONE, TOO. MAKE SURE
THE VIOLET WIRE IS STILL ON S4-3.

-> The red/white wire TURNS ON R143 ON SYN.BOARD (FIXED
TRANSMIT TRIMMER) DURING TRANSMIT IN MANUAL MODE ONLY.
THE RED-WHITE WIRE SUPPLIES +14V ON TRANSMIT ONLY, FROM
D125. THE VIOLET WIRE LEADS TO R143. THIS TAKES THE PLACE OF
THE CLARIFIER CONTROL WHEN TRANSMITTING IN MANUAL, AND IS
USED TO MAKE THE TRANSMIT FREQUENCY AGREE WITH THE 12
O'CLOCK CLARIFIER POSITION DURING RECEIVE. IN THE ORIGINAL
FACTORY SET-UP, THIS WAS USED TO SATISFY THE FCC REQUIREMENT
THAT NO EXTERNAL CONTROL BE ALLOWED TO AFFECT TRANSMIT
FREQUENCY OTHER THAN THE CHANNEL (CRYSTAL) SELECTOR. R143
WAS TURNED ON WHENEVER TRANSMITTING, AND THE CLARIFIER
TURNED OFF.


9) ADD A DIODE (1N4148 OR EQU): ANODE TO S4-5 (SHOULD HAVE TWO
REMAINING RED-WHITE WIRES) CATHODE TO TOP (CW) LUG OF
CLARIFIER POT. (SHOULD ALREADY HAVE ONE YELLOW-WHITE WIRE AND
THE CATHODE LEAD OF D128 ON IT).

-> The CONTINUOUS 14 volts on the orange/white wires at S4-6
feed the clarifier via the ADDED diode on transmit and
receive in CRYSTAL mode only

10) JUMPER S4-10 (ORANGE WIRE) TO GROUND NEARBY.
-> The yellow wire goes to the cathode circuit of the vfo
oscillator tube. The orange wire goes to the T/R relay, and
to ground through it ONLY on receive. Grounding the orange
wire turns on the VFO only on MANUAL mode, but for transmit
receive both.

11) SET R145 FOR REASONABLE CLARIFIER RANGE. R145 IS THE ONE
CLOSEST TO THE EDGE.

12) CONNECT FREQ. COUNTER TO SYN.BOARD OUTPUT, SELECT MANUAL
MODE, SET CLARIFIER TO 12 O'CLOCK, SET R143 (THE
INNERMOST ONE OF THE TWO TRIMPOTS) TO MAKE TRANSMIT
FREQUENCY AGREE WITH RECEIVE FREQUENCY. SELECTING SIDEBAND
AND TURNING THE MIKE GAIN DOWN MAY HELP OBTAIN A STABLE
FREQUENCY READING. R143 IS THE INNER TRIMPOT


NOTE that this file does not contemplate any mods that may have already been done. This procedure is valid for a radio that has not been modified already. It allows the radio to change the coverage of the VFO dial by setting the crystal selector to channel 1, to extend it down ten channels, or to channel 23. This will extend the VFO fifteen channels above the VFO dial's indicated frequency.

And selecting channel 9,10,11 or 12 should put the VFO dial back to its normal calibration. '

Small historical note. When this file was first written, the printer we used had only the upper-case font installed in it. Lower case characters would print in upper case. It was just easier to type a text file with the caps lock always on. Oh, the bad old days of the RatShack Line Printer One. 

73

[389]

Thankyou Chris, I had sent you a couple of messages on our ebay link, sorry to bother you there. (Do not have your email addy etc).
Anyhow re; the Man Cal button, the previous owner had the red/white and blue/white connection on the normallly closed (In OFF position > pushed in as normal),
such that when I did the mod, both the vfo and onboard 4 MHz were active together. I would listen to 11 AM switch to manual and hear the same thing,

Then on manual LSB I could hear 27.355 so both mix results were present the best getting through the filtering. After a day of studying the schematic , I woke up !
The schematic has a few double back lines that can be a optical illusion like those puzzles you get. Anyhow all good now, shifted the blue/white to normally open contact.

I was going to put a dds-vfo in it, however I fixed the bad xtal 21-23 replaced, and aligned etc, and it is like mint cond in Original state,
so maybe I will do the black ch sw d201a intead, as I have 3 of those, the other two with Grey switches.

Anyhow Chris Thankyou for these procedures, you are always on the ball with your tech knowledge. It is much appreciated.

PS, Just now Tram D201 AA board noisy connector fix kit arrived, I see $5 on the envelope, Is that with USPS or who ? As shipping costs even for littlle
items from the USA has been very expensive here, Just wondered which service you use ? In Australia it was delivered by Aramex and not Aust Post,
which USPS usually is. Another d201 tube supplier uses the same service as you, and the shipping price is much better.

73
Adrian

[2600]

The domestic part of the shipping cost is five bucks for that size padded envelope. Using fleabay's GSP only provides me with the domestic address of the transshipper who bundles packages on contract with Ebay. I never get to see what the customer has to pay to get it from USA to it's destination.

I would expect your local delivery to be made by whoever fleabay hired for the overseas leg of its trip. Strikes me they may employ more than one. I'm almost entirely ignorant of what becomes of a package once I send it to the domestic transshipper. The tracking record is better for some countries than for others. But that five bucks is factored into the asking price. No such thing as "free" shipping, only flat shipping.

73,
Chris

[389]

Chris ok, well it is a good deal, we can pay $49 usd shipping here just for a few transistors from the USA etc. A few years back it was $14.
Inflation in the USA is out of control.You need Trump back instead of the Geriatric ... WE pay 1.5 times that again in our $.