Warning: Creating default object from empty value in /homepages/11/d132647312/htdocs/Amfone/mkportal/include/SMF/smf_out.php on line 47
Viking II grid current on 10 meters




 
The AM Forum
August 20, 2019, 07:39:13 PM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: Viking II grid current on 10 meters  (Read 2522 times)
0 Members and 1 Guest are viewing this topic.
KX5JT
Contributing
Member
*
Offline Offline

Posts: 1954


John-O-Phonic


« on: October 16, 2011, 08:38:50 AM »

This Viking II was operating beautifully on 10 meters this passed week.  I tried yesterday to put it on the air and now I can't seem to get the buffer to dip in the tune up process.  Undecided
It will tune up and dip fine on lower bands... so touchy now on 10 and I can't get any grid current now... for no apparent reason...  I reseated the tubes and cleaned band switches but it's like it has a mind of it's own.  Sometimes when I turn her own there is a pronounced dip and BOOM no problem getting grid current... sure it takes more drive than other bands but that is to be expected.

Any guidance as to what to do to chase the ghost out of this machine?  It's "driving" me nuts!

John
Logged

AMI#1684
kb3rdt
Member

Offline Offline

Posts: 248


poop cup


« Reply #1 on: October 16, 2011, 02:52:28 PM »

sounds like you have resisters that needs changed or some caps went south need check that out first then try again but mine is a booger cause my osc is high so is my buffer so i got tune mine in grid turn drive up yo 5 then tune my buff to 80 on knob then fine sweet spot on osc then play from there but mine has mods done not sure what all yet i need to get the manual the doc it all but bands been good so i have not done so!! Grin
Logged
WD5JKO
Member

Offline Offline

Posts: 1763


WD5JKO


« Reply #2 on: October 16, 2011, 10:01:30 PM »


John,

   Your trying to fix something that as designed barely works. So this job you have will be challenging. I undertook the same task on a Viking I, and so did my friend at the time. I replaced the 6AQ5 driver with a 2E26, and my friend used a 5763. The 5763 was the better fit, but I always liked bigger hammers. In both conversions there was plenty of grid drive on 10m, and enough to do damage to the finals on the lower bands.

   I do believe you have an intermittent though. Could be a cap, a resistor, or any connection soldered or not like a tube socket pin. Remember the driver works the hardest on 10m. Look at the driver current, does it peak with oscillator tuning, and does it dip with the buffer tuning? Your 6146's could have reverse grid current too (big issue with Viking I's 4D32 tube) such that it only acts up on 10m.

  10m was wide open most of today...made several contacts too.

Jim
WD5JKO
Logged
KX5JT
Contributing
Member
*
Offline Offline

Posts: 1954


John-O-Phonic


« Reply #3 on: October 16, 2011, 10:53:06 PM »

Hi Jim,

Yes it's maddening since some days I kick on the filaments and she'll tune up on 10 fine.. albeit a bit touchy but she works... other days (last two anyway) I can't get her to co-operate.  (and previously as well)... she has a mind of her own on 10 meters... AHHH!!!

Yes 10 has been awesome, I worked Uruguay, Australia and France this last week and a bunch of west coast and new england and quebec.  It's OKAY with the ricebox but it's SOO much funner with the Viking II.  Timmy told me I was the "channel master" when he dropped in on me last weekend.  *gloat* (is that still a word?)

I'll guess I'll have to really get in there with some measurements on components in the oscillator/buffer section.

73 John
Logged

AMI#1684
W7POW
Member

Offline Offline

Posts: 85



« Reply #4 on: October 17, 2011, 10:35:17 AM »

Hope you figure it out John,

My Viking II has been working GREAT on 10.  No problem at all getting plenty of grid drive.

Hope to work you on 10 soon.  What time of day are you usually on?

Logged
KX5JT
Contributing
Member
*
Offline Offline

Posts: 1954


John-O-Phonic


« Reply #5 on: October 17, 2011, 10:41:04 AM »

Hey Chris, I'm usually on between 4 pm and 7 pm on 10 meters, which is when I'm awake in the afternoons.  Even if the Viking II isn't cooperating at that time, I put the ricebox on and make some noise. 

I'll likely see what I can find out on the Viker tonight after 10 shuts down.  *fingers crossed*
Logged

AMI#1684
KX5JT
Contributing
Member
*
Offline Offline

Posts: 1954


John-O-Phonic


« Reply #6 on: October 17, 2011, 10:51:36 PM »

Okay... close examination of the buffer circuit revealed a lead from the variable capacitor C22 in the buffer tank circuit had come off it's grounding terminal..... tacked it back on with a bit of solder and viola!  Yay! 10 meter grid drive again!  *fingers crossed*

Logged

AMI#1684
kb3rdt
Member

Offline Offline

Posts: 248


poop cup


« Reply #7 on: October 19, 2011, 10:49:28 PM »

ouch sounds like need new air cap hamfest fix that up!
Logged
KX5JT
Contributing
Member
*
Offline Offline

Posts: 1954


John-O-Phonic


« Reply #8 on: October 19, 2011, 11:42:56 PM »

ouch sounds like need new air cap hamfest fix that up!

No, it's working now.  It was a lead coming FROM the cap TO a ground terminal on the chassis... it had come off the solder-joint on the ground terminal... I resoldered it on.  All is well!!!

Cya on the air!
Logged

AMI#1684
Pages: [1]   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.093 seconds with 20 queries.