We seek to understand and document all radio transmissions, legal and otherwise, as part of the radio listening hobby. We do not encourage any radio operations contrary to regulations. Always consult with the appropriate authorities if you have questions concerning what is permissable in your locale.

Author Topic: Ameriton 80A will not transmit on 80m or 160m  (Read 2200 times)

Offline K2BUG

  • Newbie
  • *
  • Posts: 5
  • Karma: +0/-0
    • View Profile
    • Email
Ameriton 80A will not transmit on 80m or 160m
« on: December 30, 2015, 1617 UTC »
Hi,

I am trying to recover from a newbe mistake of a couple of years ago.  I had purchased an Ameriton 80A amp used in good shape and I was setting up my shack for a higher power transmission.  Icon 746 into a 80A with a LDG AT 1000 pro tuner (1 kw) into a Cushcraft A3S 3-element beam (10-15-20m) with a 40 meter add-on.  Everything worked beautiful testing 10-40m with the 80a operating on 115v putting out 700-1000 watts depending on the band.  The tuner did not have to work hard since the antenna was tuned to these frequencies.

I then tried 80 m and apparently I did not have the antenna tuned properly with the tuner.  When I engaged the amp and started to transmit, all hell broke lose and the transmission was very short.  After that, the amp would not transmit anything.

I unplugged the amp and took off the cover to look for damage.  To make a long story short, the relay contacts were burned (replaced), a couple of diodes were burned on the PO/ALC detector board (all replaced), and the safety choke was smoked (replaced).  Put the amp back together and it worked as before on 10-40m.  No output on either 80 or 160 m into a dummy load.  Looked a little further and 80m contacts on the band selection switch were burned (replaced the whole switch).  Amp still only shows output on 10-40 m.

Checked the radio and it puts out RF at 80 m though a little weak.  Sent it in and no damage to the radio.  Substituted a different radio which has a robust 100 w on 80 into the amp (Icon 706) and still no output.  I replaced the pertinant doorknob caps within the 80 m circuit with no effect.  I even checked the tuned input components for 80 m but the RF would have to flash back through the tube.  No problem found.

Frankly, I am puzzled because I cannot find any component defective on the 80m circuit or I have replaced them all.

Any suggestions or help is requested.  The amp acts like no RF is entering the tube on 80 m and the output on 160 m is very small (20 w).

I am new to the forum so I have not figured out if I could post the schematic. 

Thanks

Offline ka1iic

  • Hero Member
  • *****
  • Posts: 900
  • Karma: +0/-0
  • Troy, Ohio
  • Troy, Ohio. 20m Vertical & low long wire E/W,
    • View Profile
    • Email
Re: Ameriton 80A will not transmit on 80m or 160m
« Reply #1 on: December 30, 2015, 1933 UTC »
The diagram would really help and a few pictures of the rig would also help...  I am sure someone on this forum can help you...

First off check the connection between L1 and L2 in the output stage. L1 is the output for 160 meters and 80 meters.  I just down loaded the diagram BTW :-)
« Last Edit: December 30, 2015, 1944 UTC by ka1iic »
73 Vince
KA1IIC

"If you can't be anything, you can at least be annoying"

Troy, Ohio. 20m Vertical & low long wire E/W, Yaesu FT-187ND, SDRplay 2, Ratt Shack 2 meter rig, and other little bits of electronics I'm not talking about, homebrewed and otherwise... so there bleech!

Offline BDM

  • Hero Member
  • *****
  • Posts: 557
  • Karma: +0/-0
  • S/E Michigan
    • View Profile
Re: Ameriton 80A will not transmit on 80m or 160m
« Reply #2 on: December 30, 2015, 1937 UTC »
Hi and welcome aboard. Yes I'm sure someone here will help. You can also check out the Yahoo Group Ameritron Amps, Tom W8JI manages that group and he is one of the design engineers for that amp. I'd include a link, but Yahoo Groups is not responding (down?) right now  :P
Radios -- Perseus SDR // Icom IC-7410 // Tecsun PL-660 // Panasonic RF-5000A --Antennas-- Pixel Pro 1B loop - 82' fan-dipole at 40' - tuned MW/BCB 40" loop and 100' receive only dipole
-Brian--North of Detroit--MI-
1710/KHz the MW Pirate Clear Channel (not so much anymore "sigh")

Offline K2BUG

  • Newbie
  • *
  • Posts: 5
  • Karma: +0/-0
    • View Profile
    • Email
Re: Ameriton 80A will not transmit on 80m or 160m
« Reply #3 on: December 30, 2015, 1952 UTC »
Hi,

All connections on L1, L2 solid.  Also L3.  RFC3 replaced as was c17 which is on the 80 m circuit

Thanks

Offline K2BUG

  • Newbie
  • *
  • Posts: 5
  • Karma: +0/-0
    • View Profile
    • Email
Re: Ameriton 80A will not transmit on 80m or 160m
« Reply #4 on: December 31, 2015, 1600 UTC »
Some additional symptoms with use over the past several days of use.

The current tube is declining in amp power.  A couple of bands have completely faded to a max of 300 w with 90 w in. (10, 15, 20m).  40m has reduced power to 500 w.

Two backup tubes that have been in storage for 5 years(?) do not provide any boost of signal at all ( one new unused and the original tube which was putting out 700 w when removed).  100 watts in and 100 watts out.

Bad tubes or something else going on?

Went back and carefully retested the original tube from storage and it exibited the same symptoms as the tube I was using.  200-300 watts output on 10, 15 & 20m and 500 w on 40 m.  Some other circuit failing.  Any suggestions?

« Last Edit: December 31, 2015, 1734 UTC by K2BUG »

Offline BDM

  • Hero Member
  • *****
  • Posts: 557
  • Karma: +0/-0
  • S/E Michigan
    • View Profile
Re: Ameriton 80A will not transmit on 80m or 160m
« Reply #5 on: December 31, 2015, 1834 UTC »
K2, you may want to also swing this question by the Ameritron Group

https://groups.yahoo.com/neo/groups/Ameritron-Amps/info
Radios -- Perseus SDR // Icom IC-7410 // Tecsun PL-660 // Panasonic RF-5000A --Antennas-- Pixel Pro 1B loop - 82' fan-dipole at 40' - tuned MW/BCB 40" loop and 100' receive only dipole
-Brian--North of Detroit--MI-
1710/KHz the MW Pirate Clear Channel (not so much anymore "sigh")

Offline redhat

  • DX Legend
  • ******
  • Posts: 1324
  • Karma: +13/-0
  • USA
  • Music is my drug.
    • View Profile
    • Email
Re: Ameriton 80A will not transmit on 80m or 160m
« Reply #6 on: December 31, 2015, 2028 UTC »
I've burned up band switches before doing stupid stuff, check there.

+-RH
Somewhere under the stars...
WinRadio Excalibur/305 w/ a chi-town resonant loop, Kenwood KDC-U356 for mobile listening.
Please send QSL's and reception reports to xfmshortwave [at] gmail [d0t] com

Offline ka1iic

  • Hero Member
  • *****
  • Posts: 900
  • Karma: +0/-0
  • Troy, Ohio
  • Troy, Ohio. 20m Vertical & low long wire E/W,
    • View Profile
    • Email
Re: Ameriton 80A will not transmit on 80m or 160m
« Reply #7 on: January 05, 2016, 2052 UTC »
Just hit me...  Is the driver automatically cutting back on drive due to some defect in the amplifier?

Somewhere I remember that happening to me but when and where ???
73 Vince
KA1IIC

"If you can't be anything, you can at least be annoying"

Troy, Ohio. 20m Vertical & low long wire E/W, Yaesu FT-187ND, SDRplay 2, Ratt Shack 2 meter rig, and other little bits of electronics I'm not talking about, homebrewed and otherwise... so there bleech!