DAK IX Plate Current
Ze...@webtv.net
The meter on my Dak IX shows in the red when flipped to measure plate
current.Can someone explain what plate current is and why it is burying
the meter.As always I will appreciate all info.
Thanx
Zeb
tn...@muck.net
The plate current meter is there to give you an idea of how the
final amplifier tube is adjusted or functioning. I do not know what
tube this is, but in general terms, if this radio has SSB, and if you
key up the radio without any modulation, you should get no power
output. With the radio in this state you should be able to read
what is called the idle current of the tube. This should be low.
You use the plate current meter and adjust the idle current to a
specific value.This is an internal adjustment that does not needs to
be done very often.
This same plate current meter will rise up when
power is developed. Do not confuse this with a power meter
and adjust the radio for maximum plate current. This could
destroy the tube. Misadjusting the external plate and load
controls (if this radio has them) can also make the plate
meter go to high.
When on AM, with no modulation, you are still developing
power, so the plate current reading will read above the idle current
reading, when the radio is on AM.
The red on the meter, is probably there to let you know when
your pulling more plate current than the tube should have.
If the meter is burried, then one of four things are probably
happening. The plate current is actually high because of a
misadjusted idle current (bias), or misadjusted plate and load
controls, or the plate supply voltage dropping resister has been
strapped (shorted). It can also be caused by a faulty plate current
sensing circuit.
Whatever it is if the current is actually to high it can damage
the tube. Good luck.
Toll Free
It is an AM only rig.
It should only run in the high middle of the meter.
If you are burying the needle, either your tube is shorted, or you are
running your radio misaligned.
There are two capacitor adjustments that you can make. Place a tone at the
mic input, and adjust those for max output on the meter (power, not plate
current) on the radio.
If you are getting low or no power output, then your tube is more than
likely bad.
These where a PLL02A Cybernet chassis with a tube modulator and final.
All around decent radio.
Toll Free
--
Remember.... Technicians make it happen!
Toll Free
http://www.bigradios.com/tollfree
One of the Big Johnson Boys in the Dome!
Every woman likes a man with a great big Johnson!!!
Mobile 51
!>
dennis W. Ostrowski
>
> The radio uses a 6L6GC or 6DG6GT in the final.
That (the larger 6LQ6 tube) is the shunt
modulation tube, not the RF amplifier tube (unless
someone heavily modified the radio and made it
very illegal!
The RF amplifier was a smaller tube, like a 6BQ5.
> It is an AM only rig.
Correct. I believe it ran a Cybernet mobile
radio chassis in a big, big, cabinet.
> It should only run in the high middle of the meter.
>
> If you are burying the needle, either your tube is shorted, or you are
> running your radio misaligned.
Or lost the negative bias supply for the control
grid of the RF amplifier (final) tube...
Just my 2 cents worth!
Dennis
#12
Toll Free
My DAK never had a 6LQ6 in it!!!!
As a matter of fact, neither of the tubes in it had a plate cap on them...
Are you thinking of something else????
--
Remember.... Technicians make it happen!
Toll Free
http://www.bigradios.com/tollfree
One of the Big Johnson Boys in the Dome!
Every woman likes a man with a great big Johnson!!!
dennis W. Ostrowski wrote in message <35ED5E25...@lucent.com>...
>Toll Free wrote:
>>
>> The radio uses a 6L6GC or 6DG6GT in the final.
>
> That (the larger 6LQ6 tube) is the shunt
>modulation tube, not the RF amplifier tube (unless
>someone heavily modified the radio and made it
>very illegal!
See above
>
> The RF amplifier was a smaller tube, like a 6BQ5.
>
>> It is an AM only rig.
>
> Correct. I believe it ran a Cybernet mobile
>radio chassis in a big, big, cabinet.
Yes, PLL02A
>
>> It should only run in the high middle of the meter.
>>
>> If you are burying the needle, either your tube is shorted, or you are
>> running your radio misaligned.
>
> Or lost the negative bias supply for the control
>grid of the RF amplifier (final) tube...
True
dennis W. Ostrowski
>
> Dennis,
>
> My DAK never had a 6LQ6 in it!!!!
>
> As a matter of fact, neither of the tubes in it had a plate cap on them...
>
> Are you thinking of something else????
Sorry Toll,
I meant to say (or should I say type) 6L6GC, not
6LQ6......
The 6L6GC is the MODULATOR tube....
Yes, the DAK uses high-level modulation, by
shunting current from the final during the
modulation peaks, so the actual modulation
envelope actually gets inverted. I believe the
technique is called 'Heising' modulation or
something like that..., but I can't find any
references to tube modulation circuitry in any of
the new books I have around here at work...
Dennis
#12
Toll Free
You can stick a 6L6GC in the final, though. That will take it up to about
(give or take a watt) 10 bird watts.
That is the way I ran mine, with double the capacitance in the power supply.
Toll Free
--
Remember.... Technicians make it happen!
Toll Free
http://www.bigradios.com/tollfree
One of the Big Johnson Boys in the Dome!
Every woman likes a man with a great big Johnson!!!
dennis W. Ostrowski wrote in message <35EEBE54...@lucent.com>...
dennis W. Ostrowski
>
> It is the "Heisenberg" modulator.
Are you sure?
Or are you just pulling my leg?
> You can stick a 6L6GC in the final, though. That will take it up to about
> (give or take a watt) 10 bird watts.
>
> That is the way I ran mine, with double the capacitance in the power supply.
What is really needed is a voltage doubler on
that high voltage supply so you could run those
tubes at 800 volts instead of what they are
running at now!
Dennis
#12
Toll Free
name of the man who invented the particular modulator technic that you had
described the radio as using.
Your right... You could voltage double the power supply, but then you would
have to at the minumum do a bit of work to the pi network in it, as the
impedance would change greatly!
Toll Free
--
Remember.... Technicians make it happen!
Toll Free
http://www.bigradios.com/tollfree
One of the Big Johnson Boys in the Dome!
Every woman likes a man with a great big Johnson!!!
dennis W. Ostrowski wrote in message <35EF0931...@lucent.com>...
dennis W. Ostrowski
>
> If memory serves me well, it is the "Heisenberg" modulator... That was the
> name of the man who invented the particular modulator technic that you had
> described the radio as using.
OK. I still have not found an old enough
reference book yet...
I guess if it was a Heisenburg modulator, maybe
they would call it Heising modulation?
> Your right... You could voltage double the power supply, but then you would
> have to at the minumum do a bit of work to the pi network in it, as the
> impedance would change greatly!
Good point,.... but maybe if the impedance stayed
the same, and the plate input current increased,
then input power would be greatly increased, and
hopfully the output power would do the same....
Have a good weekend,
Dennis
#12
dmil...@gmail.com
> Hi
> The meter on my Dak IX shows in the red when flipped to measure plate
> current.Can someone explain what plate current is and why it is burying
> the meter.As always I will appreciate all info.
> Thanx
> Zeb
dmil...@gmail.com
> Hi
> The meter on my Dak IX shows in the red when flipped to measure plate
> current.Can someone explain what plate current is and why it is burying
> the meter.As always I will appreciate all info.
> Thanx
> Zeb
dmil...@gmail.com
> Hi
> The meter on my Dak IX shows in the red when flipped to measure plate
> current.Can someone explain what plate current is and why it is burying
> the meter.As always I will appreciate all info.
> Thanx
> Zeb
Guglielmo Marconi
>Hello,I know your Dak9 Final bias post was a LONG time ago but I have one
>with the same problem and have tried everywhere and everything to find out
>where and what the adjustment is, no one seems to know.Did you ever figure
>it out?If so I would really appreciate it if you could post it hear or even
>better if you would send the info to me at the following. dmil...@gmail.com
>
I was one of the engineers at M.H. Scott Corp that helped design the finals
in the Dak Mark 9 CB. There is nothing special about them and they really
are terrible finals, but what we didn't know at the time was that selling
a CB with tubes, there would be a Shit-load of retards asking how to adjust
plate current.
Guglielmo
Donald Mills
Garland Blake
>ood linears The meter on my Dak IX shows in the red when flipped to measure plate