[Kenwood] TS-830S etc. HOW TO TEST TUBES IN THE RIG

[Bill]

hey kENWOOOD LIST  MODERATOR please fix the list so that our replies go to the whole group instead of just the post-er.  Sure will save me some typin'...
OK gang, here's how I test the tubes in any hybrid rig:
Into dummy load, warm up filaments.
SSB mode.
Get access to the BIAS pot.
TX mode, observe plate current, should be normal idling current of 50-60 ma.
If not, carefully adjust bias pot for correct idling current. If you cannot get it, stop here and do troubleshooting (filaments really on? ACC plug in place? Metering problem? Cathode resistors open ckt? etc).
With rig in TX, increase your BIAS control for max plate current, then observe that the tubes can hold it there (whereever it is, should be 100-250ma) for at least 2-3 seconds.  Then IMMEDIATELY reduce the BIAS pot back to normal idling current.
If the plate current comes up with the BIAS pot, then drops off more than about ten percent fairly quickly, you have weak finals. 
If you cannot get over about 150mA AND you cannot get at least 85 watts on any band, you have one or more bad tubes or a power supply or screen grid voltage problem.
If the plate current comes up nicely and stays steady or drops off less than ten percent, slowly, you have good finals.
To test the driver tube:
Tune rig for max smoke, any band. Switch meter to ALC, allow rig to rest a bit.
Key up again in CW mode, max output, and watch the ALC. Should come up and stay up.  If it drops off more that about ten percent of full swing quickly, you have a bad driver tube. If it hangs well, and doens't drop off, or drops just a little bit and slowly at that, you have a good driver tube.
RX mode, let rig rest a bit.
Now, switch to plate current on the meter. TX again in CW, max output.
Swing the driver tune (or preselect for some rigs) from one end of travel to the other.  Observe that plate current rises and falls smoothly as you tune the control. If it's jerky or jumps at all, your driver tube is out of neutralization. Only cure is to change it, as this is not adjustable in most rigs. Have assortment of 12BY7's available as you own the rig. Don't throw out one that is unstable.. it may work fine in another rig! 
Go back to SSB and double check your idling current.  Book says 50-60 mA, you can run around 30-40 just fine.
b
 Rick Markey <kn3c@arrl.net> wrote:I've seen that twice in my 830. Both times it was the 12BY7 driver. 
Replacing it brought the power back to normal. My 830 is still making 
rated power with the original finals from 1980.

de Rick, KN3C

----------
From: John Williamson[SMTP:john_maria@hhinternet.com]
Sent: Wednesday, November 20, 2002 22:13
To: kenwood@mailman.qth.net
Subject: [Kenwood] TS-830S Power output

Hi - I have a TS-830S that has low power out on 17 (50 Watts), 12 (15 
watts)
and 10 meters (10 watts). Everywhere else it is 110 watts except 40 where
it is only 80 watts. Also, the drive on 75 meters seems low. I can not
drive it into the ALC range without turning on the processor - when I do I
can get it into the alc range with the mike gain at 10 o'clock and the
processor level turned to 9 o'clock. Any suggestions where to look would 
be
appreciated. Thank, John N4HV



- - -

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Larry Wilson KE1HZ kenwood-owner@mailman.qth.net

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