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Author Topic: What to do with a beat up Viking 1  (Read 9270 times)
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WA1HZK
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« on: March 29, 2009, 09:28:28 PM »

OK
I have a Viking II to use that is supposed to work but with it came a Viking I that's in real beat condition. The meter and most of the tubes are gone and there's the usual Hammy Hamebone mods to fix. Naturally the beat up Viking I looks like more fun. What have you guys done for a final in those things? Do you bite the bullet and spend the bucks on E-Bay for a 4D21 or do you rip the thing apart & put something else in? I'm thinking 813? What have you guys done? What are the weak points in the output tuning network? Can it take maybe 1600 Volts if I FW bridge the HV? Your thoughts before I tear into this.
Keith
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« Reply #1 on: March 29, 2009, 09:50:26 PM »

A 4D32 is only about twenny bux, Keith.  Very cheap for what it is.  The RF section in the Viker is Fine Business; it's the mudulator that needs help.  Drill 'n' blast the mudulator, mebbe build in a VFO.

Whatever mods you do make sure you do it in the spirit of the 50's.  Hand brace 'n bit drill to make sure you mar the front panel; cut holes with a can opener; use a slobbering copper to carbonize all the compoennts and use some acid core flux as a bonus  Grin
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« Reply #2 on: March 29, 2009, 09:54:26 PM »

Yeah, I know it's cheap but an 813 X 811's would be more fun! It's a huge chassis, lotsa room for new iron. I got to get Budley to describe his Viking-Bud...
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« Reply #3 on: March 30, 2009, 02:14:44 AM »

  I'm interested in this too! Got a stripped chassis with no cab to start with.
Was thinking of a pair of 4D32s for the best power versus plate voltage since I doubt that the tank can handle much over a KV plate after you add 100%+ mod voltage. Just a little dust on one of my working ones lit off like a firecracker and I had to carefully clean out the cap.
  The plate tranny and choke is rated for good enough current to be reasonable with just the RF load and use an external modulator.
Wouldn't take a lot of surgery  and still look stock on the outside.
  Heater current would be close but without any of the audio section  or rectifier load might just make it. Anyway adding another filament tranny would be easy without the mod tranny there or even a bigger plate tranny would fit.

 I will be watching....

Bill, KB3DKS in 1 Land
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« Reply #4 on: March 30, 2009, 07:21:05 AM »

Hi ...had this conversation with Tim WA1HLR about EFJ vikings...if I remember correctly he said going above 900 to 950 V was risky with stock plate tuning components ... the spacings tend to confirm this .... an 813 would be similar to an art13 usage at about 150W or so ... I offered using a couple of 4X150's at 900V ...would be very conservative in application and would operate at about 2.5k Ohm plate Z ...since the plate dissipation would be low, could allow use of a MUCH less noisy cooling system, maybe oil immersion .... must use low Z screen V stuff ...see Eimac app notes to avoid distortion .... the 4x150's will require more drive, maybe the 6aq5 driver can provide and maybe not ... just got to be too many unknowns to proceed .... so I chickened out and made a plate and mounted a pair of 6146's .... they are stable to 40 m and showing some instability on 20m ...will probably add single ended neutz circuit as time permits ... evidently this is why EFJ submounted the 6146 in the Viking II ...it is hard to find tube(s) that can be as easily driven as a 2E26/6146 to the appropriate power level ...73...John 
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WD5JKO
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« Reply #5 on: March 30, 2009, 07:28:38 AM »


Keith,

   Back in the 1970's the 4D32 was a lot scarcer than it is now. I modified a junk Vik I in about 1975, and I did an 814 and then 813 conversion. I few details:

* Beef up the RF driver, 5763 or 2E26

* Neutralize the 813

* FW bridge the HV; B+ will be about 1400v, and the plate tank did not arc for me. It might for you though.  Remove the B+ wiring from harness to minimize HV leakage and arcing possibilities.

* Get modulator B+ externally. I used a pair of 8417's at 600v B+. Today 811's might be a better choice, or use a big solid state modulator.

* Bigger mod transformer with appropriate turns ratio, with reactor + oil coupling cap


This rig ran about 200 watts RF input, and 150 watts RF out with decent modulation. Getting a lot more power will require a lot more work.


I gutted this rig at some point while I was building another up with ultra modulation. The pi-network components make one nice transmatch!

Good Luck!
73
Jim
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N3DRB The Derb
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« Reply #6 on: March 30, 2009, 07:42:24 AM »

get rid of stock audio driver section with a 12B4 driver toob and use teh stock driver transformer as a slinging transformer. stuff one of he hammond P-T124E in there instead. You will have to add a another mic gain stage, 6c4 with a internal gain pot ( set it and forget it ) between the first mic amp and the 12B4. So there is some drillage and blastage involved. the 12B4 is basically more or less a miniature 9 pin 2A3 or 6B4 with a 12 volt fil. the plate impedance is SUPER MEGA BAD low. much better than a triode connected 6AQ5.

or you could go push pull as soon as possible in the mic stage with a phase inverter setup and make every thing after that push pull as well right up to the mod tube grids......

bottom line is here is no "right way", only what you wanna try.
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N2DTS
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« Reply #7 on: March 30, 2009, 09:08:29 AM »

While I think its fun to mess around with the old stuff, putting an 813 in seems a bit crazy.
Most 'ham' stuff was on the light side stock, trying to double the power output seems futile.
Why not just build an 813 rig if that is what is wanted?
The power supply would not be good for an 813, the filiment is light, the audio power way low, rf drive is too low,
the chassis would already have a buch of holes in it....and it does not even have a vfo....

813, 2000 volts, 200 ma, 400 watts in, about 300 out.
You could do 811a's at 2000 volts with bias.

On the other hand, the 4D32 works well at 1200 volts and below.

You have a pile of old marginal 100 watt transmitter parts, it would be foolish to try to get more out of them in my book.
Best you could do is to get them working well at the 100 watt level, use them in something else, or as spares.

Brett
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« Reply #8 on: March 30, 2009, 09:49:04 AM »

I agree that doing a major change makes absolutely no sense if you value your time spent for no real gain.

The 4D32, as mentioned, is readily available and cheap since the USAF released thousands of hoarded ones for a radar system that had been scrapped decades earlier. I picked up a NIB pair for $20 total about 2 years ago off Ebay as spares for mine.

You can also use a 829B, 5894, 7854 and a few others of that type. When the USAF forced Raytheon to curtail civilian sales of the 4D32 in the mid 50's Johnson came out with a 829B change bulletin that was rather simple.

Carl
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WD5JKO
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« Reply #9 on: March 30, 2009, 10:30:59 AM »


I did my Vik I conversion at a time where I had NO money, and lots of free time. I hit the books so much that I was able to pass the 2nd Class radio telephone exam cold turkey, and then went for the 1st while I was there, also cold turkey. I passed that too! In my case, the whole effort was a wonderful learning experience for me, and it opened the door for me into the broadcast industry.

I agree with others however that as a project to do, the choice is questionable. Then again, if you have the hulk sitting there, and a junk box of parts, have fun, and see what it will do.

Jim
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N2DTS
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« Reply #10 on: March 30, 2009, 01:18:48 PM »

I would be more tempted to use the parts to build a real nice 100 watt rig in a new cabinet, or rack mount it.
It might be fun to build it with seperate decks for power supply, modulator and RF, with lots of room on each.
Or put in two 4D32's and build a seperate 811 mod deck with its own power supply.

That way, you are putting the parts to good use, and ending up with something nice, hifi, and reliable, with loads of fun building and designing.

I remember working on many old rigs that had no room for better parts, or extra stages, extra holes left over, and looking poor, and wondering why not just use the good parts and build something right.

Brett
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« Reply #11 on: March 30, 2009, 02:49:56 PM »

The Viking One is a great little rig. When my last 4D32 ran out of emission, I built a little chassis with 3 x 6146B tubes on it and floated it right above the original 4D32 socket. I simply ran the wires down and soldered them right up to the 4D32 socket. It works great from 160 - 10 meters. I ended up pulling out the 807 modulators and all the speech components so it is simply an RF deck. I solid stated the HV supply and it has never complained with the RF tubes pulling 300 ma at 725 volts. I modulate it with an external 811 deck that has its own 1250 volt supply and a Thordarson 300 watt mod transformer. I call that rig my Viking 3. The tank circuit looks like it might handle 1000 volts, but if I recall correctly, there are some fixed value caps that switch in on 160 meters that might be problematic. Should be a fun project.


* viking3.jpg (17.77 KB, 210x704 - viewed 421 times.)
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« Reply #12 on: March 30, 2009, 04:06:12 PM »

At one point, I tried the exact same thing on a 32V3, two 6146 tubes on a board right above the 4D32 socket.
It did not work through, must have got the pin out wrong somehow.....

Brett
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« Reply #13 on: March 31, 2009, 01:52:06 AM »

No old Viking is too bad to scrap or rework! I have this wonderfully finished example painstakingly done with several layers of clear coat over an ingenious "cat-piss and dents" theme.


* jvik.jpg (16.4 KB, 351x198 - viewed 443 times.)
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« Reply #14 on: March 31, 2009, 07:23:50 PM »

The 829B sounds like the ticket - a 75 cent tube that is hard to kill! I built a nifty 10M rig around a 829 modulated by a pair of 807s for 10M on the last cycle and it was FB. 829B does take a bit of grid current (drive). You should be able to do 100 Watts input.

Mike WU2D
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KM1H
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« Reply #15 on: March 31, 2009, 09:18:51 PM »

Johnson claims 90-95W out with the 829B mainly to keep within ratings. Never tried it but have seen a few over the years at hamfests.

The 5894, 7854, and all the Motorola clones are also everywhere and dirt cheap, often NIB as nobody seems to want them.


Carl
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WA1HZK
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« Reply #16 on: March 31, 2009, 10:08:15 PM »

Russian?
http://cgi.ebay.com/GMI-11-gmi11-500W-Tube-Brand-New-With-tube-Socket_W0QQitemZ200269459947QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item200269459947&_trksid=p3286.c0.m14&_trkparms=72%3A1234|66%3A2|65%3A12|39%3A1|240%3A1318|301%3A0|293%3A1|294%3A50

One of these with an outboard modulator would be cool?
Just looking for an excuse to play with this tube. Looks like the lower voltage will be OK.
Keith
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Carl WA1KPD
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« Reply #17 on: April 01, 2009, 10:19:16 AM »

W1JZ built one up into a nice lookng rack mount transmitter.
Black crinkle and all.
I have seen in person at Nearfest last year and saw some pics of it somewhere on the net

Carl

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