Bob, although it is not unusual for the BIG BOX Ameritron amps to let the smoke
out of the caps at some point, it is most unlikely to have the diodes blow. In
fact in the many years I have been repairing these amps and owning about a
dozen or so of my own, I can never recall ever seeing a diode go in them.
Caps, yes, and routinely, along with the bleeder resistors opening up. But
yet, even just replacing the caps, the amp still runs normal for a good long
time afterwards. There has to be some underlying problem there someplace. I
am not familiar with the Wd7Y board. But 10 caps should never blow up.
-----Original Message-----
From: Bob Gibson <w5rg@yahoo.com>
To: Louis Parascondola <gudguyham@aol.com>; Amps <Amps@contesting.com>
Sent: Wed, Dec 24, 2014 1:45 pm
Subject: Re: [Amps] AL-1200
I have added a WD7S ABOARD WHICH HAS 10 FILTER CAPS ON IT..I do need to check
the input voltage and the wires to the transformer.. that is one thing I have
not done..I replaced the step start because he has trouble before with the
original relay and resistor burning out.. With the original P/S board the
diodes would blow, now with the newer WD7S boards, the filter caps pop.. I know
the last time I replaced the board it was one of mine that I had in a AL-1500
so I know it worked before I switch it out on his.. He lives in OKLA and I live
in Florida so I'm headed back up on Friday to help him out..
Bob W5RG Almost 60 years in Ham Radio
From: Louis Parascondola <gudguyham@aol.com>
To: w5rg@yahoo.com; Amps@contesting.com
Sent: Wednesday, December 24, 2014 12:34 PM
Subject: Re: [Amps] AL-1200
Yes, make sure the plate transformer is NOT using the green wire instead of the
brown/white lead. If the green wire is used it can very well up the HV to 3900
volts will eventually stress out the filter caps and they will let go. This is
exacerbated further buy very high line voltage. Some people could have up to
250v. Also it is prudent to modify the capacitor system to use 10 capacitors.
I make a homebrew kit with instructions on how to install it to add 2 more
caps. Unless the amps blows up right away at turn on there is NOT a problem
with anything else.
-----Original Message-----
From: Bob Gibson via Amps <amps@contesting.com>
To: Amps <Amps@contesting.com>
Sent: Wed, Dec 24, 2014 12:51 pm
Subject: [Amps] AL-1200
I'm having a problem with a friends al-1200 amp.. He is 80 years old I'm 71
and we can not figure this out.. I have replaced the stock P/S board twice..
after a short time it blows out.. I have replaced it now with a WD7S HV board
and again it blows the caps.. I have replaced the step-start board with a W7RY
board.. still samething.. I headed back up to try to work on this thing again
this weekend.. any ideas would sure help out..Bob W5RG Almost 60 years in Ham
Radio
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