Herve,
Thank you so much for your helpful suggestion. The diode was bad, I replaced
it, and the amplifier works perfectly again. I am feeling good again!
The only diodes I had were 1000V/2.5A. Do I need to get a 1A diode instead?
I learned a good, inexpensive lesson and will not try a used tube again without
prior testing.
Stan, K5GO
>
> From: Hervé BIRAUD <f5hry@wanadoo.fr>
> Date: 2005/08/14 Sun AM 03:45:31 EDT
> To: <k5go@cox.net>, <amps@contesting.com>
> Subject: Re: [Amps] AL-1500
>
> Hello Stan,
>
> If you can "monitor" the following problem (i.e. the needles of both
> meters showing the same values and moving exactly the same way),
> it is just a matter of grid current readout (the tube is fine).
>
> Replace the 1N4007 (300-0266) in the filter board (check it out before
> to be sure it's dead !), and your AL-1500 will work fine again ! It's
> very usual that this diode burns when a flashover occurs in an AL1500.
>
> Hope that helps.
>
> Vy 73
> Herve F5HRY
>
> www.win-test.com
> www.fy5ke.org
>
> ----- Original Message -----
> From: <k5go@cox.net>
> To: <amps@contesting.com>
> Sent: Sunday, August 14, 2005 3:16 AM
> Subject: [Amps] AL-1500
>
>
> > I'm sick after using one of my AL-1500 amplifiers to check an unknown
> 8877. High voltage came up fine but when I closed the relay with about 5
> watts drive, it immediately blew both mains fuses. I replaced the defective
> tube with the original, and it does not blow fuses but the grid current
> shows higher than it should with very little drive and does not decrease
> with heavier loading. I knew something was wrong and stopped at about 400
> watts before applying more drive. Any input before I start diaassembling the
> thing would be appreciated.
> >
> > Stan, K5GO
> >
> > _______________________________________________
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> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
> >
>
>
>
>
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