Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives :: Books
Support This Site: Contributors :: Advertise


It is currently Dec Sun 17, 2017 7:11 am


All times are UTC [ DST ]





Post New Topic Post Reply  [ 7 posts ] 
Author Message
 Post subject: tom bonomo mods
PostPosted: Nov Thu 30, 2017 10:51 pm 
New Member

Joined: Sep Wed 27, 2017 3:05 pm
Posts: 1
looking for tom bonomo's mods for the viking-1 and2 from the er mag.6-8-98 art. 110-111-112. I have a viking 1&1/2 I think it has his mods. Tube was changed to a 8643 any help would be appreciated thank you RED N9GHE


Top
 Profile  
 
 Post subject: Re: tom bonomo mods
PostPosted: Dec Fri 01, 2017 12:30 am 
Member
User avatar

Joined: Nov Sat 07, 2009 11:37 pm
Posts: 1775
Location: Sayreville, NJ 08872
n9ghe wrote:
looking for tom bonomo's mods for the viking-1 and2 from the er mag.6-8-98 art. 110-111-112. I have a viking 1&1/2 I think it has his mods. Tube was changed to a 8643 any help would be appreciated thank you RED N9GHE


All the issues you mentioned seem to be available for purchase:
https://www.ermag.com/index.cfm?v_link= ... k%20Issues

_________________
Pete, WA2CWA - "A cluttered desk is a sign of genius"
http://www.classicradiomanuals.com


Top
 Profile  
 
 Post subject: Re: tom bonomo mods
PostPosted: Dec Fri 01, 2017 12:59 am 
Member
User avatar

Joined: Jun Sun 19, 2011 2:31 pm
Posts: 4812
The original final for a Viking 1 was a 4D32 and it sounds like someone substituted the later 8643 final which would fit the same socket and probably works OK with rewiring. At one time the 4D32 finals were very expensive, probably the "Collins tax" since the 32V series uses this final also but then the FAA dumped a ton of them on the market in the late 1990s and the price is very reasonable now.

The Bonomo mods mostly monkeyed with the audio system extending the low end down far lower than the original designer intended and then increased modulator output and opined that the lower power rating on AM compared to CW was because of modulator shortcomings. Or it might just be that the Viking 1 designer followed the ratings of the final tube manufacturer-amazing how those Johnson designers actually followed good design principles... The Viking 1 and 2 are the best built of the Johnson line and are quite reliable in stock form.

I don't recall any published mods substituting the 8643 final tube but because of the price for a few years I expect some different modifications were tried. Johnson also suggested the 829 tube as a substitute (slightly reduced ratings) because of a 4D32 shortage during the Korean conflict.

If the final loads properly and the wiring changes were neatly done then it is probably fine to leave it as is at least until you need a new final. Think long and hard before making audio and other modifications to any of these vintage rigs because unlike the original designers who were trained as engineers to take a systems approach many hams try to treat these rigs as a group of discrete circuits which they really are not.

Rodger WQ9E


Top
 Profile  
 
 Post subject: Re: tom bonomo mods
PostPosted: Dec Fri 01, 2017 1:59 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 3381
Location: Monterey California USA
8643 was a 5984 on steroids which in turn was a beefed up 829B. At one time they were plentiful as they were used in Motorola's Motrac high power VHF mobile radios. Not any more. Now that 4D32's are cheap I don't see any reason to not use them in the Viking I, either.

There are some speech amp mods that might be useful now that goal is not maximum "cut through the QRM" power but I agree, many of these ham mods are messing with a design that a number of degreed engineers came up with after considerable outlay of R&D money and for good reasons. One mod that makes sense is a PTT relay for the Vikings. I dislike using that toggle switch even though that is the "old buzzard" method.

I wish there were a mod to stop that roller coil from arcing right at the "sweet spot" where you need it. :evil: Yes, I know the usual cures, it's just a nuisance and like the bad penny, comes back sooner or later.

_________________
WB6NVH
California Highway Patrol Radio
Bell System Mobile Telephone History
http://www.wb6nvh.com


Top
 Profile  
 
 Post subject: Re: tom bonomo mods
PostPosted: Dec Fri 01, 2017 3:33 am 
Member

Joined: Jul Tue 21, 2009 1:38 pm
Posts: 690
Location: SW WA state
Ah... 4D32's and 8643's... A nice trip down memory lane...
I have a 32V3, and put in a supply of spare 4D32's... I think I had two before the FAA tubes became available, and one of those was gassy!
I'm still on the stock, early 1950's tube, but have the one spare and several of the FAA tubes now.
I also have a stockpile of NOS 8643's left over from my two way days.
The VHF Motorola Motracs used them as finals, and we had a LOT of Motracs in service back in the day...

I don't like to modify rigs unless absolutely necessary... One candidate that comes to mind is the Gonset VHF amps using 826's... At least half the tubes I have are gassy, no idea how long the others will last, so I was considering the possibility of an 8643 conversion there, but I think the easiest thing to do is to just move the amps along.
Best of Luck with your Viking I/II... I gave away three of them recently. I'll stick with the Viking Valiant and the Viking 500...


Top
 Profile  
 
 Post subject: Re: tom bonomo mods
PostPosted: Dec Fri 01, 2017 5:34 am 
Member

Joined: Apr Thu 20, 2017 2:35 pm
Posts: 36
Hi Red,

Check your email. The ER documentation is all there as you were looking for.

73

Al


Top
 Profile  
 
 Post subject: Re: tom bonomo mods
PostPosted: Dec Sat 02, 2017 3:57 am 
Moderator
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 22134
Location: Somers, CT
Red

Also check out Tom Rauch's webpages on the Vikings, if you haven't already.

https://www.w8ji.com/johnson_ranger.htm

https://www.w8ji.com/johnson_vfo_chirp_jump.htm

Regards

Pete k1zjh

_________________
Just because it can be done doesn't mean it should be done.


Top
 Profile  
 
Post New Topic Post Reply  [ 7 posts ]  Moderator: Sandy

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 7 guests



Search for:
Jump to:  


















Privacy Policy :: Powered by phpBB