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Trying to deal with tube finals.

johnny9

johnny9

Active Member
Dec 3, 2013
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bikini state
the small drive tube in my tram d201 glows blue flames when keyed but my father says its normal..but not from what ive read on wikihow about tubes?any thought on that?

captain k,,i think i have gotton more from your original post than i have from any other threads on the web..thanks for sharing this as im trying to learn and it gets frustrating at times for sure;)

when you say to "dip" the load plate after adjustments and go a lil past to have cleaner audio,does that mean to back off a lil and watch the meter go down a hair,or go up and watch the meter go down,so the tubes last longer? sorry if im sound stupud with some of these terms lol.
im asking so i can do this part on my tram d201 radio,as ive finally got it adjusted then read your article and was told to do the same with my radio as in your thread,,thanks,john
 

If your tube glows blue it is gassy and should be replaced. As for your question, advance the loading control slightly and watch the power meter. It will drop slightly....not too much.....and leave it there.This results in the best linearity.
 
thanks ck. i even tryed a 3rd tube last night and it glowed blue when keyd up also..i didnt think wiki would have bad info but i cant argue wih my father lol.
i wil just get new 12by7 tube there not that pricey.
the 12by7a i tryed also glowed blue when keyd up.
 
captain K, read the thread again lol to make it stick with me hopefully.
i dont have a dummy load..can i use my antenna like one of the guys on here did? page 2 iirc? or do i need to wait till i can get a dummy load?

i run a astroplane with flat swr,s if that matters..

also,im set up with a 4 watt deadkey,do i need to def go to the 1-2 watt deadkey to tune the abc 250 amp?

just confuses me a lil,thanks
 
Antenna is OK if the SWR is really low. A dummy load is for people who don't want to cause interference on the air while testing. It also helps when adjusting a transmitter to know that the results will be the same as when operated into a properly tuned antenna which should present the same 50 ohms load as the dummy load does.

As for the carrier level going into the amp....I couldn't tell you. I have no knowledge of that amp or most CB type amps in general. i am MUCH more familiar with amateur amplifiers and their drive requirements are VASTLY different and we don't deal with ridiculous carrier to peak ratios of things like 1 watt "dead key" and "swinging" to 20 watts peak. that is a CB thing. Amp tuning techniques however are the same regardless however for basically all tube type amps.
 
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thanks ck..well at least now i can get started on the amp today..
im still making room for the tram and amp on the bottom shelf thats a disaster at the moment.
i like to keep the hinged lid lifted when talking cause the tubes are so cool lol..hopefully one never explodes on me,that wouldnt be good.

i read most all these old tube amps for cb was for the most part made for 4 watt deadkey and no higher than 5.
i will read a few things again before i start on this in a few hrs..

another great weekend in the bikini state,cold yesterday and hot today:headbang
im from here and cant wait to move where its a lil colder someday before its too late,hopefully tn can wait for me lol..i prob couldnt handle the real cold most are used to..:)
 
i will try to make this short but not easy for me lol..i seen my tram was leaking a few spots where it was sitting,opened it up,has a cap leaking,and a zillion more thats growing fuzz lol.. so covered it up till i can get the caps all changed...the ole radio means a lot to me and want it done right.

so,hooked up the old pres grant mobile and forgot it was hooked to a 4 amp power supply at the time..it says its deadkeying 10 watts.

then hooked up the abc 250 plus tube amp..radio to meter,meter to amp,antenna to correct side of the amp..seemed correct hopefully.

i ate supper and let the amp warm 15 min..then went to ch 15 and keyed up to adjust tune and load..
still only showed the 10 watt key up,no matter what i did with the tune/load it was the same..amp clicked and tubes seemed to be all in working order btw.

turned the drive up a lil past half way,still no difference on meter.still 10 watts.

then a few diff channels,everything i did was kinda fast,didnt wanna screw up something but everything seemed fine.except the meter reading lol.

i noticed when on ch 1-7 the amp wouldnt click and connect when i keyed the mic?
ch 8-40 the amp clicked and made great contact..seems weird?

then i realized the power supply was only 4 amps and read i need 6-7 amp p.supply so i stopped and let the amp sit 5 min like was told and let the fan do its thing,then shut the amp down..

then like a dummy realized if the radio is dead keying 10 watts thats prob to much since i read most old tube amps need 4 watts or less to run them?

but,i also realized when i key up just the radio,it has no swing,just the 10 watts it dead keys?

i honestly dont think the 4 amp p.supply was the issue,but rather the radio having 10 watts but really dont have a clue..so for now,
im back quite,as im used to it..any thoughts,john

edit;just turned the radio only back on and it dead keys 20 watts on 19,12-13 on ch 12 and 8-10 on the lower channels,,i assume thats kinda normal..its been rainy here and lightning now so un pluged everything for now.
 
are you using a peak meter to watch for swing??

ever thought about getting some newer modern equipment to get you on the air reliably then work on getting the older radio's and amps restored if you really like them.

not a good idea to be even be trying to put 10 watts into an amp if you don't know what it can take, start way on the low side. everything has to match,, you cant just take a radio that is dead keying anywhere from 10-20 watts and plug it into an amp and expect good results
 
i agree..i was into this with the tram in my head and all the reading ive done.
then had a brain fart when i tryed it with the mobile radio..

not sure what a peak meter is..im using a older big micronta 3 range power/swr tester.. i also have a new astatic pdc2 swr.power meter but didnt hook it back up..when it was hooked up the tram would really swing it..
i also had the old one hooked to the tram and it didnt swing it at all.

good point,maybe i should go back to the new meter and not this old one.
the old one looks like new and is real big so i can see it w/out glasses lol.

yes,im gonna get things right before messing with the amp again as the amp seem so far to be the best thing out of the 3 boxes of stuff i got recently..

not into new stuff but i may be headed that way as i will get a ham radio sooner or later,prob sooner.

i may go get dads pristine cobra 2000 gtl that has lots of extras..just gotta trade him out of it lol..im working on my free 2000gtl right now..
 
changed meters and the mobile is only dead keying 1.5-2 watts and dont show any swing lol..still no difference..
i have a thread "abc electronics 250 plus amp" that i posted what i feel the problem is..

and captain k you were correct on the old midland having that clock knob in the off position lol..got it working and hooked up just now so maybe i can use it for the time being..will see tomorrow..also hooked up the siltronix vfo to it;)
 
johnny9 said:
changed meters and the mobile is only dead keying 1.5-2 watts and dont show any swing lol..still no difference..
i have a thread "abc electronics 250 plus amp" that i posted what i feel the problem is..

and captain k you were correct on the old midland having that clock knob in the off position lol..got it working and hooked up just now so maybe i can use it for the time being..will see tomorrow..also hooked up the siltronix vfo to it;)
Click to expand...

From what you're saying here, and in a previous post, I believe your dead key is too low for this amplifier. I have seen that on some amplifiers, where they need at least 4 watts to key the thing up. You didn't say what your new meter is, but if it reads average power instead of peak, that could explain why you didn't see any "swing" on the meter. You might want to take the whole setup to a tech and have him set it up to match for you.

73,
RT307
 
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the new meter is a astatic pdc2 10/100/100 watt swr meter..with my old tram it deadkeyed 4-5 and swings 15-16..but i had to retire it for a while..

hooked up this old midland 898b and still the same with the amp keys up with all 3 radios,,the amp has a small tube 6kv6 and then a bigger 6bq5,then the next 3 in line are 6jg6 tubes,and the center tube of those 3 seem to no be keying with the others.
im no tech but i feel its to do with that tube.

its all on the side as of now till i can afford someones newer junk lol,and het my old stuff checked out..
hope everyones having a great weekend ;)
 
couldnt remember if i put this out there,but after talking with alan the tube guy and repairs old tube trams,amps etc etc,he said it was normal for the tubes to glow blue when keyed up..
i read to other things online today that also say when your keying up your amp tubes glow blue..
so im guessing the center tube thats not blue when keyed may be the culprit..

every 4 watt keyed radio i tryed did the same thing.

hard to belive there arent many knowledgable people with tube stuff anymore,but i guess money talk when you wanna buy a amp nowadays.

sorry to have highjacked your other thread ck..
 
"then hooked up the abc 250 plus tube amp..radio to meter,meter to amp,antenna to correct side of the amp..seemed correct hopefully."
You can not read the output of your amp with the meter at the input.
Rich
 
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