Viking Ranger lives - briefly

[N9axl]

I finished recapping this, checked it out, plugged it in and - IT Lives.  briefly. After about 10 minutes there was the most brief and quiet "pop" and it died.  

There was no smoke, no flame, no explosions. I suspect either some arcing because of dust/ dirt or some short where a wire got disarranged. Thoughts???  Until then it seemed fine. Saw plate and grid voltage, meters and lights ok, filaments lit, transformers wasn't getting hot.v12 seemed somewhat warm. It just sat there and sort of hummed.

 I checked underneath and saw nothing obviously smoked or burned.

Now, the fuse popped as it should. Turns out that I forgot to replace the fuses which were both 3 amp and had been sitting in the barn in the plug for 25 years also. (Slap to head) off to hardware store for 3 amp and 5 amp fuses which this unit uses.


and then I managed to lose one of the prongs for the plug. It was there and it vanished off the bench. (Second slap to head). I have ordered a new plug ( and will put a grounded plug on later.

[KB2WIG]

K,

Get rid of that Johnson plug, and go with a modern 3 wire power cord. You can stuff a inline fuse/holder on the inside if you don't want to drill and blast.


klc

[N9axl]

I will be doing that. I noticed that on the Viking 2 Johnson eliminated that plug. I just bought a Viking 2 CDC for my next project and there is a single 8amp plug inline with sw1. Sensible. Some research to do on that. I got because I'd never seen a CDC version.

[W4AMV]

On a Ranger 1 in restoration process had a similar event and was somewhat hard to fine. The 0.01 uF/600 V TVI filter caps sprinkled around the line input and other locations, develop cracks in the outside casing shell. The 110V will arc over from the cap, briefly, popping the fuse, but the cap looks perfectly fine! Takes a magnifying class or jeweler loop to locate the bad disc cap. Hope that may help.

Alan

[N9axl]

Thanks. I'll order some caps and look into that. Glad it sounds like something simple.

[Pete, WA2CWA]

Thanks. I'll order some caps and look into that. Glad it sounds like something simple.

Personally, I would find the problem first before ordering parts. Guess work doesn't always solve the problem.

[N8ETQ]

    Yo'

       Wonder what flavor the Ranger is? Real early,
(Switches HV via the function sw.) Medium early (No
contact on SW4B Position 6(?)) or late model (flat
metal plate above function Sw. with 6AL5 and a 12AT7
and No contact on SW4B Position 6)

    In all cases you can pull the 5R4 and not have to
worry about HV. The 6AX5 does the LV. That soft pop you
heard was probably the fuse blowing, (They do that).

    With just the 6AX5 plugged in you should find 300
VDC in there along with filament voltage and if it
has the 6AL5 you will also find Bias voltage on the
6146 grid.

     The VFO, Buffer and Multiplier should be working
at this point, listen for the VFO on your RX. Low level
audio stages are also functional and you should be able
to see AF to the 1614 grids. If all looks good add the
5R4 back in.

     If your just plugging into the wall be aware that
filament voltage can approach 7.0 VAC on the ranger.
Measure it. They were designed for 115. Also the 300V
can go as high as 440 V.

     Good luck,

73

/Dan

[N9axl]

it's a late model. I did replace the cord with a proper grounded cord and inline fuse. That doesn't fix the problem. I removed the high voltage rectifier, turned it on, and it ran for ten seconds on standby.  I suspect I will be spending the winter redoing the wiring.  There's a short somewhere. I will redo the posee cord and vacuum the inside. perhaps metal shavings or a wiring snippe

[N2DTS]

A shorted cap is MUCH more likely then a shorted wire.

[N8ETQ]

A shorted cap is MUCH more likely then a shorted wire.

   Yes I agree, You could pull the 6AL5 too and see if the bias supply
caps are shorted or in backwards..

/Dan

[N9axl]

yep. found a cracked line .005 line cap. this is happening with radio on standby and high voltage rectifier removed along with accessory plug which would seem to isolate it to this area.

[N9axl]

I replaced one obviously cracked bypass cap. at off nothing happens. on stand by it turned on, ran for a few minutes and then blown fuse. there was a flash under the 6ax5 rectifier - short - have pulled out and redone the new electrolytics I installed. Thought 2 33 u f in series were enough with 270k ohm resistors - positive end on large resistor and negative at ground on transformer as original.

large 50w resistor rusted. new one $17 at Mouser

by the way I,don't expect to have anyone walk me through this. these postings are mostly my notes on processes.
. if u want to Elmer me bless you.

[N8CMQ]

I finished recapping this, checked it out, plugged it in and - IT Lives.  briefly. After about 10 minutes there was the most brief and quiet "pop" and it died.  

There was no smoke, no flame, no explosions. I suspect either some arcing because of dust/ dirt or some short where a wire got disarranged. Thoughts???  Until then it seemed fine. Saw plate and grid voltage, meters and lights ok, filaments lit, transformers wasn't getting hot.v12 seemed somewhat warm. It just sat there and sort of hummed.

 I checked underneath and saw nothing obviously smoked or burned.

Now, the fuse popped as it should. Turns out that I forgot to replace the fuses which were both 3 amp and had been sitting in the barn in the plug for 25 years also. (Slap to head) off to hardware store for 3 amp and 5 amp fuses which this unit uses.


and then I managed to lose one of the prongs for the plug. It was there and it vanished off the bench. (Second slap to head). I have ordered a new plug ( and will put a grounded plug on later.

Pictures please?

[N9axl]

it's always something little. I removed the 20k resistor to get at the 6ax5 tube socket.  working on this didn't help.still a short. but then I found a bad cap- had a divot crack on the underside. On the far right of the photo.

These bad boys are all going.


Normally bare wire from positive of electrolytics to 20K resistor center cap. used 5 inch piece of voltmeter probe cable instead. flexible and no possibility of shorts. I checked the resistor and it was right on spec. 

[N9axl]

I replaced the bad cap, checked everything over, and also checked the new fused line cord.

The line cord goes hot to one side of the fuse, a jumper to one end of the terminal strip, neutral to the third connection on the strip, and ground to a lug on the chassis.picture attached.

All looks good so I set this up with a ground, a dummy load, watt meter, key,  fire extinguisher at the ready, and  plug this into my outlet strip. This is a big metal industrial strip. All controls set to what the manual says.

On standby the unit turns on, lights up, no smoke, no drama, fine. Before it went for 10 seconds on standby and blew - which turned out to be a bad cap.

When I turn it to tune, which remember turns on the high voltage, the ground fault interupt outlet, next in line from where I have no outlet strip, trips.  The fuse in the unit doesn't blow, but the GFI does.  I tried a different outlet strip. Same deal. I saw no grid current, but a small amount of plate current.

this is a dead project until I figure this out as I have no interest in burning down my house. 
Clearly there's some kind of high voltage short in the system.

[W4AMV]

Although it is not a perfect solution, using a VARIAC on a line with no GFI is helpful. If you do not have a VARIAC, I would invest in one. And if you can, an isolation transformer is also a great investment. However, I would put a priority on a VARIAC before moving forward on this Ranger. The ceramic cap that blew on mine occurred at a VARIAC line V of just under 90 V. With a Ranger line V somewhat low it was fortuitous that when it took out the line fuse, a black soot arc trace was left on the chassis leading me straight to the cap location, like an arrow! Took a magnifier to see the exposed cracking in the ceramic of the .01 uF. Since you can turn the VARIAC up to a low AC input, say 20 V or so, you can safely measure the HV and simply scale it to the 120 V level. If the scaling does not come up to the 500+V that the 6146 is supposed to have in normal operation, you know for sure I have a definite HV issue but track it back some what safely.

[AB2EZ]

There is a disk capacitor (probably .01uF) from each side of the AC line input to ground. These may take the form of a .005uF capacitor to ground... on each side of an air wound inductor. These were included, primarily, to reduce TVI. These are not compatible with a GFCI, and their effect on the level of unbalanced current to safety ground could increase when you turn on one or both of the DC power supplies.

With everything turned off and unplugged... remove both (or all four) of these capacitors.

These capacitors don't serve a useful purpose in today's context... particularly if you are using a GFCI outlet.

If you are concerned about RFI, there are much more effective ways to keep RF that is produced by the Ranger from being conducted into the AC power line via the AC power cord.

Stu

[N9axl]

Hmm. So having those caps on the line input doesn't work with a GFCI. Why is that? Does the GfCi see it as short? I will take a look at those.

I agree. I've put off getting a variac but the time has come. I think the idea I can work at low voltages and not electrocute myself will be a Selling point to my wife.

I think they're probably are some bad caps in there with,as you note, exposed cracking. I already found and replaced a few. Q

Recommendations?

The other issue is that there are only three outlets in this room I use and the GFI is the first one in the series.  So basically all the outlets will trip this. I am thinking the moving and remodeling of another room into my radio shack/work room just moved up the priority list.



 I am giving some thought to doing a trade of this unit for a working transmitter or transceiver that does AM if I can find someone with interest.

It's becoming more of a project than I have time for.

[AB2EZ]

The GFCI will trip if the current in the safety ground wire (green) exceeds approximately 5mA. The capacitors (in conjunction with the transformers they are connected to) provide lots of opportunities for current to flow from either side of the AC line (hot and neutral) to safety ground (chassis ground). Unless all of these paths are balanced to produce equal and opposite currents in the hot and neutral wires, there must be a net current flowing in the safety ground wire.  Removing these capacitors forces the two currents (hot and neutral) to be (almost) equal and opposite. I.e. neglecting unbalanced winding capacitance to ground, and capacitance between the windings that can conduct AC to ground... the AC current going into one side of each transformer's primary must be equal and opposite to the a AC current going into the other side of each transformer's primary... and there is no AC current flowing in the safety ground wire.

Stu

[KA2DZT]

I always tell folks to remove the line caps, they are not needed and can cause more problems than they're worth.  Those caps act as a leakage path to the chassis and is most likely the reason the GFI is tripping.

Fred

[N9axl]

Thank you. Thank you. I went downstairs and removed those line caps. I had already removed some of them because I took out that 117 volt ceramic outlet plug. There were other caps on the other side of those Inductor coils. They are actually almost invisible unless you look for them.

In regards to those caps - I did replace the ones around the final. There's two .002mfd and one .005mfd. These .002 caps need to handle 2000 volts so I replaced them with 6KV units. They say 1.5KV on the old cap, but I didn't want to trust 50 year old units. Complete overkill but they will be good for another 50 years now.  

The ones I pulled were actually still in spec - .0025mfd by my meter.

I still have an issue with an intermittent b+ issue. It was fine with the HV rectifier in earlier and now it blows the GFI.  Low voltage seems fine.

  That said, I fully agree that a variac and an isolation transformer are a good idea.  So I will defer any further power on tests until I get those.  I get the idea of a variac and an isolation transformer. What are you recommending in saying have both - plug the variac into the isolation transformer.

[Pete, WA2CWA]

The Apache line by-pass caps use to trip my GFCI until I removed them. Then RF from the Valiant started to trip the GFCI. Then I removed the GFCI and haven't had a problem since.

[W4AMV]

Agree with all on the line caps, they are today, more of a problem than a solution and the TVI motivation is history. I guess I bought off on the idea at the time to try to keep the Ranger as original as safely possible. On the VARIAC, that alone is a key investment in safety. The isolation transformer I added as a comment in that I got involved with working on power supply switchers and it was essential again from a safety issue as well as the ability to troubleshoot. No, the VARIAC alone will not provide the function of isolation but I do not believe you need the isolation transformer in your particular instance.   

[N2DTS]

What is the worry?
If you have a problem, the fuse blows.
If you have a big problem, the circuit breaker blows.
No reason the house is going to burn down.

GFI, variacs and isolation transformers can just cause more problems.
If the high voltage blows, you found a weak point, fix it and move on to the next failure.
Those old rigs are filled with bugs, design shortcuts, and really old parts.
The only way to get it working well is to find what blows up, burns out, gets hot, reads wrong and fix it.

For testing things, I have a 3 prong cord with a fuse in the hot wire and alligator clips on all the ends.
A 5 amp fuse is what has been in there for a while.


Also, beware of some of those no name brand electrolytic caps you can get off ebay cheap, some are no good.

[KA2DZT]

You don't need an isolation xfmr when working on equipment that has power xfmrs first in line off the AC supply.  The power xfmrs provide the isolation.  Isolation xfmrs may be useful when working on equipment that runs directly off the AC line without any input xfmrs, like most modern consumer products.

A variac is always a good piece of test equipment to have on the bench.  Best to get a 15 or 20 amp unit.  Over the years, I've collected probably over 30 variacs from small 1amp units to 30amp monsters.

Fred