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Author Topic: Ameritron AL-811 'fixes'  (Read 17582 times)
W8JX
Member

Posts: 13268




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« Reply #15 on: January 13, 2018, 02:59:52 PM »

Fixes for the AL-811(H)?

Better rear band switch, pain in the bum to replace and easily damaged.
Better case screws, as you'll need to remove them often.
Switches are a bit cheap and nasty.
Rear circuit is a pain to work on.

Fixing these would be a start...

Better fix is cut losses and get rid of it and get a real amp
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--------------------------------------
Ham since 1969....  Old School 20wpm REAL Extra Class..
W1BR
Member

Posts: 4196




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« Reply #16 on: January 13, 2018, 03:03:30 PM »

Fixes for the AL-811(H)?

Better rear band switch, pain in the bum to replace and easily damaged.
Better case screws, as you'll need to remove them often.
Switches are a bit cheap and nasty.
Rear circuit is a pain to work on.

Fixing these would be a start...

Ouch....   Grin Grin
Better fix is cut losses and get rid of it and get a real amp
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MM0IMC
Member

Posts: 255




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« Reply #17 on: January 13, 2018, 03:04:33 PM »

Fixes for the AL-811(H)?

Better rear band switch, pain in the bum to replace and easily damaged.
Better case screws, as you'll need to remove them often.
Switches are a bit cheap and nasty.
Rear circuit is a pain to work on.

Fixing these would be a start...

Better fix is cut losses and get rid of it and get a real amp

Already did. Cheesy And no, not a RM or Zetagi! Tongue
« Last Edit: January 13, 2018, 03:09:56 PM by MM0IMC » Logged
KM1H
Member

Posts: 5541




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« Reply #18 on: January 13, 2018, 03:33:03 PM »

Id like to see a better Load cap, something with a wider spacing as they spit under some loads and/or the relay bogs down. Once a few arcs the cap is ruined.
Get rid of those ancient design filter caps which are still a retarded 60's era  -10/+50% tolerance plus the equalizing resistors open.

Ive had to replace all a few times plus that PITA rear switch section and several sockets with poor tension. Also one transformer which was actually touching a tube and burnt the insulation off, great QC. Angry

Also scrap the 811H and convert the other to a pair of 572B's at ~500W. That will force more into the AL-80B if they want a 3dB increase and stick with tubes.

AND I dont want to hear about those with perfect never failed amps, we all know they exist so no need to keep repeating it.

Carl
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K9AXN
Member

Posts: 442


WWW

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« Reply #19 on: January 13, 2018, 04:18:38 PM »

Fixes for the AL-811(H)?

Better rear band switch, pain in the bum to replace and easily damaged.
Better case screws, as you'll need to remove them often.
Switches are a bit cheap and nasty.
Rear circuit is a pain to work on.

Fixing these would be a start...

Does the rear bad switch have C23, 4, and 5 clips?
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WY7CHY
Member

Posts: 1018




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« Reply #20 on: January 13, 2018, 04:56:25 PM »


Better fix is cut losses and get rid of it and get a real amp

Ah, the bias mantra never stops. Such constructive advice. We are so blessed to have your input.
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Born Wild - Raised Proud: 73
Cheyenne, Wyoming
W8JX
Member

Posts: 13268




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« Reply #21 on: January 13, 2018, 06:03:11 PM »


Better fix is cut losses and get rid of it and get a real amp

Ah, the bias mantra never stops. Such constructive advice. We are so blessed to have your input.

Some, like you, live in denial while some see it for what it really is, a cheap CB like ham amp that is basically a POS. There is no other amp built (other than old sweep tube amps) that had so little plate dissipation for rated output, none, which speaks volumes on what a cheap design it is. A 50 year old design, ie 600+ watt rated SB200, has nearly twice the safe anode/plate dissipation as a AL811H. Ameritron/MFJ could of built a modern day SB200 but choose otherwise.  
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--------------------------------------
Ham since 1969....  Old School 20wpm REAL Extra Class..
WY7CHY
Member

Posts: 1018




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« Reply #22 on: January 13, 2018, 07:47:56 PM »

Some, like you, live in denial while some see it for what it really is, a cheap CB like ham amp that is basically a POS. There is no other amp built (other than old sweep tube amps) that had so little plate dissipation for rated output, none, which speaks volumes on what a cheap design it is. A 50 year old design, ie 600+ watt rated SB200, has nearly twice the safe anode/plate dissipation as a AL811H. Ameritron/MFJ could of built a modern day SB200 but choose otherwise.  
https://www.youtube.com/watch?v=q_BU5hR9gXE
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Born Wild - Raised Proud: 73
Cheyenne, Wyoming
MM0IMC
Member

Posts: 255




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« Reply #23 on: January 14, 2018, 12:41:34 AM »


Does the rear bad switch have C23, 4, and 5 clips?


Unfortunately, I don't remember as I did the repair back in 2013 and traded the amplifier in for a better one back in 2015.  It was a 2012 model though, as it had the stickers with the date in it.
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N1RND
Member

Posts: 63




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« Reply #24 on: January 15, 2018, 05:22:05 PM »

How about a quieter fan. 
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KM1H
Member

Posts: 5541




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« Reply #25 on: January 16, 2018, 07:58:23 AM »

Quote
How about a quieter fan.

Headphones fix that issue.

If the fan bearings are OK a series resistor can slow it down a bit as the external airflow will not stop the plates from glowing into destruction.

Carl
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N1RND
Member

Posts: 63




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« Reply #26 on: January 16, 2018, 09:05:33 AM »

I  thought I heard of some one putting the fan in box and plumbing the air to the amplifier.
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W1BR
Member

Posts: 4196




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« Reply #27 on: January 16, 2018, 09:11:04 AM »

Drill holes in the 811 glass envelopes and allow cooling air to directly cool the plate structure.
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AA2UK
Member

Posts: 923




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« Reply #28 on: January 16, 2018, 11:32:13 PM »

Drill holes in the 811 glass envelopes and allow cooling air to directly cool the plate structure.
Yeah that'll work........................not
Bill, AA2UK
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N2EY
Member

Posts: 5096




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« Reply #29 on: January 17, 2018, 05:09:58 AM »

Fixes for the AL-811(H)?

Better rear band switch, pain in the bum to replace and easily damaged.
Better case screws, as you'll need to remove them often.
Switches are a bit cheap and nasty.
Rear circuit is a pain to work on.

Fixing these would be a start...

(and others)

So.....let me get this straight.....

One starts out with a brand new amplifier. Then one invests considerable time, parts and money into improving it, by replacing cheap parts with better ones, inadequate tubes with adequate ones, adding features that were left out of the original design, etc.

And if you do it all correctly, you wind up with an amp that's a pretty decent performer - at a power level that is almost what is advertised for the original stock amplifier.

Do I have that right?

73 de Jim, N2EY
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