Troubleshoot Viking Ranger II

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WB2PKR:
AD5X link...

http://www.ad5x.com/images/Articles/Ranger%20Mods.pdf

W3GMS:
Ron,

I knew Dee-W4PNT pretty well and visited him on several occasions when he was painting Johnson gear.  I do remember he had a list of mod's which he did for customers that did not want to do the mod's themselves.  His changes were fundamentally sound.  At one time, I knew the changes he did, but that was many years ago and I forget the specifics.   Dee and Howard-W3HM were good friends and Howard may have a list of the mod's that Dee did on the Ranger's.  Not sure, but I would send Howard and email and ask the question. 

I have owned a Ranger II for 35 years ago and its my daily go to rig to drive a legal limit amplifier.  A great rig and with some mods can even be a better rig.  I have never had a failure since I did mods on mine some 25 years ago. 

Some folks, me included, used the pot to vary the gate voltage on a N channel FET acting a series pass going to the screen of the 6146.  It allows one to easily tweak the output power when driving a linear amplifier. This pot was commonly located around the octal socket used as a XTAL socket.  I mounted my pot behind the socket and this allowed me to keep all XTAL functions.  You simply put an insulated alignment tool into the hole in the center of the socket and then align it with the slot in the pot shaft.  In mine, I power the 6146 off the LV supply.  This gives me the perfect drive level for a pair of 3-500Z's.  The second mod that is very common is to use the same scheme that was just described on the screen of the driver tube.  Replace the drive pot with a much higher value which lowers the stress since the series FET is doing all the work. 

6550's as modulators are a common mod as well.  In my case, I used a hot cathode phase inverter to drive the grids and this allowed me to get rid of the driver transformer.    I used a shunt zener diode scheme to bias the 6550's so they would not pull any grid current.  I also used another FET as a screen regulator for the modulators.  This keeps the screen voltage very constant. 
 
Not saying what mods you have, but some may be along the lines I described.  I do remember talking to Dee with his Ranger mods and the on air signal sounded very good. 

Dee was a great guy and is missed by many. 

73,
Joe-W3GMS               

 

N1BCG:
At some point, you’ll need to decide if you want to refer to your rig as a Ranger or not on the air. A Ranger sounds like a Ranger, although many sound great with very minor mods. After enough modifications, it’s a Ranger in looks only.

WB2PKR:
The hum was in fact from the filament supply. I replaced the rivet holding the terminal strip at the transformer with a screw, star washer and nut. That did it.  It is now pretty quiet on the dummy load. Going to try it on the air tonight.





 

WB2PKR:
Reports on the air are solid. No hum, good clean audio. Working on all bands (except I didnt try 6M).

So, some final observations, lessons learned and maybe a punchlist item or two:

- I spent too much time worrying about trying to find schematics for all the mods. Should have jumped in earlier.

- Learning how to use a scope was invaluable in shooting the problems. If you dont have one, get one or borrow one and learn how to use it. I wasted a lot of time checking component values and voltages/resistances when simply connecting the scope to the multiplier would have quickly shown me the 6CL6 wasnt working despite it checking out OK on the tube tester.

- As pointed out by Joe (W3GMS), it appears that pot installed on the crystal socket does indeed vary the screen voltage, but I wonder about this mod. Not sure I like this one. I would think that reducing screen voltage will impact the quality of the signal.  Regardless, I currently have it set wide open, but I am considering removing it as I have no plans to reduce output to drive an amp.

- That drive pot (R13) I replaced runs VERY hot. Kevin, thanks for suggesting the AD5X mod. I may do this next time I open up the rig. Right now it is assembled and off the bench in the operating position. Maybe get to this one over the summer.

It has been a fun and educational little project. Albeit, I spent WAY more time than I estimated. Good thing it is still too cold for boat work.

Thanks again to those who provided constructive comments and input.

Catch you on the bands.

73, Ron WB2PKR

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