Tube substitution in Swan finals
Ken McCoy
Pardon the cross-posting. I am having some trouble while transmitting
on my vintage Swan 400 (all tube). It seems to arc once the tubes in
transmit circuit heat up; the lack of visual evidence around sockets
and solid state components leads me to believe it is in a tube
somewhere. I have tested and replaced all tubes except the finals,
since the setting instructions are confusing to me, calling for an
external ampmeter to further adjust the bias to 55 ma (even though the
adjustment knob only goes to 50 ma)...
Anyway, the real reason for my post is that the tubes currently in the
final amplifier stage are 6146. The schematics and manual call for
6HF5. The compatibility of these separate types is unknown to me; the
settings on my Heathkit TT1 tube tester differ greatly.
Does anyone know whether these tube types are compatible, or should I
consider trying to acquire the original tube type called for in the
manual? I don't *think* there has been any modification to the
circuitry.
Please reply here or email me directly at kmc...@stetson.edu
Thanks much,
Ken KF4BQF
Steve Robertson
YIKES!! No wonder you are having problems! The 6146 is a "real"
tranmitting tube, while the 6HF5 is a color television sweep tube. The
6146 was made to go all day and night without complaining at medium
power (about 180 watts CW input for a pair). Sweep tubes, however, are
great for *INTERMITTANT* service at high power. Doing a replacement
without circuit changes is really asking for trouble. The power supply
for the Swan probably delivers voltage too high for the 6146 and that is
causing the problem.
Get the tubes that are supposed to be in there. (I don't know offhand if
the tube pinouts are the same, so be real sure that no mods were made to
the set before replacing the tubes). BTW, they won't be cheap!
73 de Steve, KE4OH
--
To get my real e-mail address, remove the characters ".xxx" at the end
of my address.
Greg Anders
--
>>>>>>>>>>>If nothing has been modified then 6146s would be a poor
substitution to say the least. FYI, the last time I checked
about a month ago 6HF5s at Antique Electronics were CHEAPER
then new 6146s, something like $10.00 ea... The 6LQ6s used
in later Swans are the expensive ones...
Greg Anders
"If at first you don't succeed......then skydiving is not for you"
and...@autopsy.sgi.com
KG6YV
Richard Carroll
6146 tubes require an entirely different socket than the 6HF5. If your
radio has 6146's, the sockets HAVE been changed and other changes would
have to have been made, possibly unsuccessfully since it is not working.
Sorry, this problem may be a tough one to solve.
Dick W0EX
fro...@megsinet.net
On Mon, 29 Sep 1997 01:03:27 GMT, kmc...@stetson.edu (Ken McCoy)
wrote: Ken: 6hf5 tubes are the type of "TV sweep tubes" you should
use. 6146 tubes are used in more modern rigs and probably are
screwing things up in the SWAN. I have a SWAN 350 and it is like
yours. I use 6hf5 tubes, and it is a real performer. Visit the old
remaining TV repair shops and make an offer to get their 6hf5 tubes!
Or you could peruse the YELLOW SHEETS or QST to find a tube guy or
maybe even RF PARTS Co. will still sell some 6hf5's in matched pairs.
Good Luck! SWANs are cool.
Paul, N9GTQ
1RealHope
There is a site in Maryland that repairs Swans. They have government
contracts that pay the bills and do the Swan stuff for giggles - really, I
had them do some work and the prices were amazingly cheap!
There is a 40 Meter net at lunchtime weekdays where Swan affectionados
gather to talk about such things and the guy who runs the Swan piece of
that shop is often on. He's a real nice guy. Forget his call.
If you absolutely cannot find them let me know and I'll try to run the info
down here somewhere.
Guaranteed they will restore it for real short money - and do a nice job of
it. DavidC AA1FA
Patrick Keogh
Wow...why do people do things like replacing sweep tubes
with 6146's!
I just purchased a new-old-stock matched pair of Sylvania
6HF5's from Antique Electronic Supply of Tempe, Az. Seems
that they have lots of already matched pairs in warehouse
bins...they did not charge me extra for matching (I asked
the salesman over the phone if he could check stock to see
if he had Sylvania...these were the matched pairs). Price
was $34.00 with shipping. Not bad considering real 6146B's
are twenty bucks each.
I would recommend replacing the 6146's with the 'HF5's only
if you are experienced with such surgery and are willing to
track down the sockets for the 'HF5's (this may be more
difficult). Neutralizing a Swan of this vintage is a
little tricky also.
Good luck...don't get in too deep. Remember, if all else
fails, you still have a fine receiver!
Pat Keogh
WB9GKZ Green Bay, WI
ke...@netnet.net
J M Noeding
On Tue, 30 Sep 1997 08:19:24 -0400, Steve Robertson
<stephen.h...@cpmx.saic.com.xxx> wrote:
>Ken McCoy wrote:
>>
>> Pardon the cross-posting. I am having some trouble while transmitting
>> on my vintage Swan 400 (all tube). It seems to arc once the tubes in
>> transmit circuit heat up; the lack of visual evidence around sockets
>> and solid state components leads me to believe it is in a tube
>> somewhere. I have tested and replaced all tubes except the finals,
>> since the setting instructions are confusing to me, calling for an
>> external ampmeter to further adjust the bias to 55 ma (even though the
>> adjustment knob only goes to 50 ma)...
>>
>> Anyway, the real reason for my post is that the tubes currently in the
>> final amplifier stage are 6146. The schematics and manual call for
>> 6HF5. The compatibility of these separate types is unknown to me; the
>> settings on my Heathkit TT1 tube tester differ greatly.
>>
>> Does anyone know whether these tube types are compatible, or should I
>> consider trying to acquire the original tube type called for in the
>> manual? I don't *think* there has been any modification to the
>> circuitry.
>>
>> Please reply here or email me directly at kmc...@stetson.edu
>>
>> Thanks much,
>>
>> Ken KF4BQF
>
>YIKES!! No wonder you are having problems! The 6146 is a "real"
>tranmitting tube, while the 6HF5 is a color television sweep tube. The
>6146 was made to go all day and night without complaining at medium
>power (about 180 watts CW input for a pair). Sweep tubes, however, are
>great for *INTERMITTANT* service at high power. Doing a replacement
>without circuit changes is really asking for trouble. The power supply
>for the Swan probably delivers voltage too high for the 6146 and that is
>causing the problem.
>
>Get the tubes that are supposed to be in there. (I don't know offhand if
>the tube pinouts are the same, so be real sure that no mods were made to
>the set before replacing the tubes). BTW, they won't be cheap!
>
>73 de Steve, KE4OH
>--
>To get my real e-mail address, remove the characters ".xxx" at the end
>of my address.
another problem using 6146 type instead of sweeptubes is
6146 type never live 18-20 years with heater voltage on. 6146 sicken
and emission decreases when not operated, while the sweep tube does
not have such problems. The 6146B may not last 5 years, while many
sweep tubes may still work after 20 years.
Jan-Martin Nöding,LA...@online.no
Collecting WW2 comm.equipment, VHF/UHF/SHF operation/experiments
old...@mdi.ca
fro...@megsinet.net wrote:
>On Mon, 29 Sep 1997 01:03:27 GMT, kmc...@stetson.edu (Ken McCoy)
>wrote: Ken: 6hf5 tubes are the type of "TV sweep tubes" you should
>use. 6146 tubes are used in more modern rigs and probably are
>screwing things up in the SWAN. I have a SWAN 350 and it is like
>yours. I use 6hf5 tubes, and it is a real performer. Visit the old
>remaining TV repair shops and make an offer to get their 6hf5 tubes!
>Or you could peruse the YELLOW SHEETS or QST to find a tube guy or
>maybe even RF PARTS Co. will still sell some 6hf5's in matched pairs.
Great to hear other guys using the old swans!
I put a pot in the screen voltage supply and I am able to run the rig
with it only puting out 5 watts or full power, the pot is a 5 meg ohm
if I recall and when set for low power you can never over heat your
finals and burn them out,even with no ant connected!
6hf5 tubes are hard to get, so are all most any tube that will work.
Good luck finding them!
jdag...@gate.net
On Sun, 05 Oct 1997 06:57:00 GMT, la...@online.nospam.no (J M Noeding)
wrote:
Most sweep tubes that I have always used in my Drake fail to last
more than 2 or three years. I converted the 6JB6's in my T4XB and
have had them in there for more than 2 years and no loss in power out.
Regards
James
WA4BZJ