Topband: Mod for TS-850

[Martin]

Hello topbanders ,

some guys on the elecraft-reflector asked about how to connect a
transverter to a TS-850. I translated a german article in www.mods.dk
for them.
After the modification it is also possible to easily connect a
preselector, rx-antenna, preamplifier/rx antenna or whatever.
Maybe this information is useful for those topbanders
running a TS-850 or similar rig.
---------------

John, the mod is not an easy job and you will dig deep in your ts-850.
There is no way to build it back to original.
Also, you will need the schematics and some brain.
I did the mod several years ago, i dont remember how long it took, but it was 
pretty much work.

When you come to the point where you read ŽCut the cablesŽ, please 
be very careful and better think twice! The cables are short,
so cut them in a clever way. Maybe i switched the cables to obtain proper length,
i dont remember exactly. Before you cut any cable, check if they are long enough.

If you have tools and material to make new cables (a crimping device, cables and those tiny plugs
that are used inside the ts-850), you are safe.

Also, note that the lightning protection diode is no longer in the rx-path when a transverter
or other stuff is connected to IF IN!

Here we go:
  
Have your schematics at hand.

Looking at the rear of the TS850, you see -at the right side- several cinch-plugs ACC,ALC etc.
Between the 2 upper and 1 lower rows, there is enough space for 4 additional cinch-plugs.


How to do it:
Remove top cover.
Remove bottom cover.
Remove filter unit.
Unsolder pl-plug.
Remove rear cover.
Drill 4 holes for the cinch-plugs, about 16mm spacing.
Locate cables CN1 and CN2 on the IF-unit.
One of them leads to the RX/TX-relay-board. Cut it.
Solder both ends to 2 adjacent cinch plugs you mounted to the rear panel.
Mark them Ant out, IF in. 
The other cable (DRV OUT) leads to the FINAL UNIT (FINAL IN). Cut and solder to 2 adjacent cinch plugs.
Mark them DRV out, Final in.

Double and triple check the connections. Is FINAL IN next to DRV OUT?
Is ANT OUT next to IF IN?
Check with the schematics.

Check again. If you goof here, you WILL destroy your rig when you transmit.

Thats it. 

Install rear cover, pl-plug, filter unit, bottom cover, top cover.

For normal operation, the plugs have to be brigded- drv out<>final in    ant out<>if in.

For transverter operation, drv out goes to the tx-path of your transverter.
Your transverters rx-path goes to IF IN. Remember: no diode!

For preselector-operation, use ant out and if in.

For rx-ant operation, use IF IN . Remember: no diode!


Good luck, and... Check the schematics!

-- 
Mit freundlichen Grüssen

Martin                 mailto:dl1iaq at gdxf.de