AX-9909 Data?

[N8ETQ]

   I don't know if it was the same rig but I converted my GC300
to 4X150's back in the day (1992 ish?) and sold it to TPH. small
world huh?

   The 4X150 tubes are Identical  in all respects to the AX9909
spec wise. The mechanical differences were easy to overcome
with the GC300.  I used air system sockets but I suppose the
flat ones out of a T-195 Mod. Deck would work OK.

 GL with that

/Dan N8ETQ

     Hey VH - John w8tph converted the  GC/300 using a pair of 5894s and then sold it to Glenn wa3gpe. So if you hear him on 80 give him a call. It is an easy change over.HOPE YOU ARE FEELING BETTERwith your cold.

[W3GMS]

Very interesting thread on the old Globe Champ.  Bert, WA3JYU put in a 4CX300 years ago in his Globe Champ and its worked very well.  If I remember, he put a small box in to raise it above the chassis which I am assuming allowed him to pressurize the air into the socket.  I believe he uses 811A's as modulators and it sounds quite good. 
Joe, W3GMS   

[Jim, W5JO]

IIRC Motorola's tube is an 8643. It looks like a 5894 but is a little fatter around the middle,
has a 3rd fin on the plates, and the plate pins are a little fatter as well. They used to be expensive, but now that no one wants or uses Motracs any more, they are cheap as dirt.

They have a considerably higher dissapation rating than a 5894 and they have 12v filaments allready. I am planning to use 2 of them whenever I get around to re doing my Glob Chump. the Slab Bacon

Using a pair in my 300A now.  They work just fine.

[n5op]

An 813, eh? I have two of those, with sockets. But, how well would they do with only 1000 V on the plate? I thought they liked singing at about 2000 V or so.

[n5op]

And, it sounds like the 8643 might be the ideal replacement, requiring minimal modifications. Looks like I need to get serious about checking into this... How common are the 8643s?

[Jim, W5JO]

Probably you are going to go to the larger fests, OKC, Tulsa, or Belton to find them.  Look for Motorola Boxes with the number 97-(or the letter S)136A01 on them.  Sometimes the tube will be marked with 8643 but most of the time it won't.  It will have the Motorola part number on the envelope. 

It will stand a lot of abuse.

[ke7trp]

You can get replacement 9909s on ebay from a guy oversea's,  They are the same as the PE1/100 or OS-51

They are on ebay for $50 a SET right now.  THey Drop right in.  They are listed the same as the ax9909. However,  I have found the rig does about 30 watts less output.  I dont know why.    I can load up to 220 watts out on my original AX9909s.  I run them at around 200 watts out and have for years now.  The OS51 tungsrams seem to make 170 to 180 tops. If thats ok with you, Buy them up. 

Also.. Keep in mind, I did NOT neutralize the Rig after trying the OS-51s.  I did not want to desturb it as the rig was at full output with the AX9909s.  It might come up full power if I did neutralize it with the OS-51s.

Also.. there are 6083s that are the same.   

I paid the $200 for new ones.  I dont want to have to hack up my Globe Chump and $200 to me is not that big of deal to keep originality.  A set should last a very long time.  Mine has 50+ years of use and they still run full output.

Clark

[n5op]

Thanks for all the input and advice.

I'm certainly not in a hurry to modify the rig. I inherited it from my Dad (W5JHJ, SK in 2007), who was the original owner. He bought it new in 1959 and, lacking the facilities to build it, had another BC engineer friend assemble the kit. At one time, I saw the original manual and even sales receipt, but they seem to have walked out since then. Dad had documented what changes he'd made in the manual, so I'll have to rediscover them. I know what a few are.

As far as I know, it has the original AX9909's in it. I got my Novice in 1970 and I used it for several years strictly for CW. After about 1970 or so, Dad's activity dropped off. It probably didn't get turned on much after about 1976 or so. He would fire it up every few months to make sure everything worked, but only briefly. He ultimately got an FT-102, which caused him a lot of trouble until he sent it to NC4L, after which it was nothing short of a wonderful rig. He was active with it for a few years, but as his health declined, so did his activity.

At one time, Dad had a spare set of the AX9909s but they, too, are no longer in evidence. I fired up the rig in 2006 and made a QSO on 40 m. It made full output then. Given that I probably will not use it or its companion Hammarlund HQ-170 on a daily basis, the longevity of the final tubes is probably not my biggest worry. But, like my Dad, I always want a contingency plan and spares on hand. Maybe I should stop worrying, bite the bullet and shell out for a pair of AX9909s!

Kim N5OP

[ke7trp]

Just buy some OS51s and put them in a Drawer.  Thats what I did.  Those 9909s should last your lifetime if you tune and load it Properly

C

[The Slab Bacon]

The big problem with 9909s is having the plate pin out the bottom instead of the top. Dirt around the socket and/or mistuning would cause arcage at the plate pin and crack the bulb.

If you are planning to keep the 9909s in place (or something similar) be sure to keep the final sockets good and clean and free from dirt. also make sure the pin grabbers are making good, tight contact with the plate pins.

[n5op]

All good advice. Thanks!

I hope to have everything up and going in June some time (I'll be out on a field project for all of May) and I'll be sure to make myself known on some of the AM spots.

Kim N5OP