A question or two regarding the Johnson Viking Ranger.

[KC2TAU]

So when I fired up my recently acquired Johnson Viking Ranger today I noted that I was unable to obtain any grid drive. I thought the Chernobyl resistor had gone so I took off the VFO cover to take a look and am unsure if it is the original but it measures well and the VFO tracks smoothly. I think I'm just going to replace it anyway as I can't find any wattage rating on it and it looks a bit old. Is the original resistor black in colour? For some reason when I started the Ranger back up the grid drive was back but the issue is now that when I switch to phone mode the modulator current is now 120ma or so which is what it should be at it's peak.

I remember when I was making a QSO yesterday the modulator current was a bit lower than half scale when not speaking which sounds a bit high. This excessive modulator current exists across all bands. When in phone mode the output power rises all the way to it's maximum(nearly 50W)instead of staying at it's resting carrier wattage.

I can speak into the microphone and hear myself on a receiver but I did not do this for long considering the modulator current. The audio level pot works correctly as well. Perhaps I moved R35 which controls the resting modulator current while cleaning up the installation on the replacement capacitors for the 10uf 700v capacitor. I just would like a second opinion before I proceed any further.

In addition I have the VFO apart with the side and top cover off and I noticed that the VFO is off calibration by about 50khz or so. It was spot on yesterday and so could this incorrect calibration be due to the VFO case being partially disassembled?

Finally the manual mentions setting the drive control at 5 and then adjusting the buffer until 2.5ma of grid current is showing. Does one peak the buffer control and then lower the drive control until 2.5ma is shown or does one leave the drive control around 5 and then adjust the buffer control to the required amount of grid current? I can achieve 2.5ma either way,I'm just wondering which is the right way.

This is my first foray into AM so I'm bound to have a few more questions,any help would be wonderful.

[WQ9E]

Lack of grid drive could have easily been a tube or switch not making good contact, if it shows up again you can track it down.  I would definitely replace the resistor and mounting it inside the enclosure (as done originally) will result in more rapid stabilization.

If you haven't replaced the bias filter caps, DO SO immediately.  Once you have fresh caps in make sure the modulator bias is close to what it should be (- 28 volts) and then set the proper modulator resting current via the sliding tap on resistor R-35.  CAUTION!  Make sure the power is off and the filter caps are discharged before getting around R-35 (or anything else for that matter).  Also, the wire used to make R-35 is extremely fragile so make sure that the clamp is properly loosened and slide it carefully.  If the modulator current is too high slide R-35 tap towards the grounded end, if too low go in the opposite direction.

The lack of a cover will affect the frequency.  Once it is on and warmed up for at least 15 minutes you can check/recal.

With the grid, peak the buffer and then adjust the drive for the proper level.

If the VFO tuning is rough, you need to clean and re-lube the ball reduction unit.  If it is really rough or slips do so quickly because the old and dirty lube will cause wear to the shaft and bearings resulting in terminal damage to the reduction drive.

Last but not least, Welcome to AM!

Rodger WQ9E

[KC2TAU]

Lack of grid drive could have easily been a tube or switch not making good contact, if it shows up again you can track it down.  I would definitely replace the resistor and mounting it inside the enclosure (as done originally) will result in more rapid stabilization.

If you haven't replaced the bias filter caps, DO SO immediately.  Once you have fresh caps in make sure the modulator bias is close to what it should be (- 28 volts) and then set the proper modulator resting current via the sliding tap on resistor R-35.  CAUTION!  Make sure the power is off and the filter caps are discharged before getting around R-35 (or anything else for that matter).  Also, the wire used to make R-35 is extremely fragile so make sure that the clamp is properly loosened and slide it carefully.  If the modulator current is too high slide R-35 tap towards the grounded end, if too low go in the opposite direction.

The lack of a cover will affect the frequency.  Once it is on and warmed up for at least 15 minutes you can check/recal.

With the grid, peak the buffer and then adjust the drive for the proper level.

If the VFO tuning is rough, you need to clean and re-lube the ball reduction unit.  If it is really rough or slips do so quickly because the old and dirty lube will cause wear to the shaft and bearings resulting in terminal damage to the reduction drive.

Last but not least, Welcome to AM!

Rodger WQ9E

Hey Rodger,

Thanks for the words of advice. Isn't it annoying when something stops working and then, after you've already disassembled it, it starts working again? I was talking to a friend today about it and he said something to the effect of "You know,it's probably on vacation."

All of the electrolytics have been changed on this Ranger except one that sits right next to the audio potentiometer. I'll need to get at that one. I'm wondering what it's function is.

Thanks for the ideas about the calibration. I figured having everything in the open would bother it. Thankfully the VFO is very smooth and it tunes very smoothly as well.

Thanks for the welcome. I plan to use this Ranger with my HQ-129X which should be a lot of fun as the Hammarlund sounds lovely on AM.

[WQ9E]

The USPS cured an intermittent in a Ten Tec transceiver I purchased.  I finally gave up on getting it to "intermit" and it has been working well for over a year.

If the electrolytic caps for the bias supply are new (I think they are located on the underside of the keyer sub-chassis if your Ranger has that update) then check the bias at the modulator grids to make sure -28 volts is present.  If not find out why and if it is present then an adjustment of the modulator screen voltage should set things right.

The HQ-129X will make a nice match with the Ranger.  With a good antenna on 75 the Ranger has enough power when conditions are reasonable and it will do very well on the higher bands (and 160 when it is quiet).   

[KC2TAU]

I checked the modulator grids and they measured close at -27.4V and proceeded to adjust R35 and now the resting modulator current is around 65ma or so. I'm going to button it back up and continue testing.

[KC2TAU]

One other thing I noted is that someone substituted in 6L6GA's in for the modulator tubes and I'm wondering if this is such a good idea. The GA's are rated at 15 less volts for maximum plate voltage and 3 watts less on the plate than the 1614's.

I noted that in the manual they state the plate current for the modulators as being 500V and the screen voltage as 300V,both of which are above the 6L6GA's specifications. I know you can push the envelope a bit with older tubes but I've heard that exceeding the recommended maximum screen voltage is a much worse idea than exceeding the maximum plate voltage.

[w3jn]

It's doubtful that the 15 volts and 3 watts will make much of a difference.  Tubes are much more forgiving that other components.  I'd run 'em til I found a pair of 1614s at a hamfest.  It's not like you're running 'em with full bore audio for hours at a time in class A, like a hifi amp.

[KC2TAU]

I was reading various documentation about modifications to the Ranger and I don't really want to mess around with the audio side too much as I've been told it sounds good. However I would like to do the drive control modification explained in AD5X's modification document for the sake of reliability. I just need clarification on the procedure. His article states to add a 5 watt 5k resistor to the ground end of the potentiometer and I cannot really tell from the photo where the other end goes to. It looks like it goes to the function switch. He also mentions using a 7.5k ohm 5 watt resistor in line with the LV supply. His pictures shows the LV supply as a red wire so I wonder if it is red on all Rangers. Certainly a DVM could tell.

Is any additional stress placed upon a stock Ranger by swapping the modulator tubes for 6550's or 6CA7's?

Regardless I believe a more pressing issue is the fact that,at best,my Ranger only gives out about 40 watts carrier and about 90W PEP so I believe the 6146 is a bit tired.

[KC2TAU]

In addition when replacing the filter capacitors does anyone stiffen them up in terms of their value? Wouldn't that somewhat reduce sag under load?

I still need help in regards to the drive pot modification. I'd like to do the modification but I really want to have clarification so that I am able to do this right the first time.

[k7pp]

You may have an intermittent 6AX5 rectifier tube.
If this happens again,  go to tune position and look at the meter.
If you have no osc or buffer readings then you have no low voltage.
I was plagued for months with this problem and it only seemed to do it after
I got the thing back in the case.

Also,  the ground side of R35 sounds like it's blown open.
The unit might work fine on CW but when you go to phone,  the screen grids on the
modulator tubes will rise to B++ and tubes will draw about 130ma in idle state.
I've got two Rangers and they both have eaten one of these resistors.
If it blows open at the top of the resistor where it connects to HV then you will have no idle current but some modulation readings as the screens go to zero when keyed.

GL & 73's

Pete

[KC2TAU]

Hey Pete,

Those are some wonderful pictures. You have a great setup there! The Ranger is working fine though the 6146 might be a little bit tired so I need to take care of that. I'm fiddling about with putting in some 6L6GC's I have in the modulator to see if that gives any improvement over the current 6L6GA's that came with the rig.