On Aug 14, 2005, at 12:45 AM, Hervé BIRAUD wrote:
> 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.
A flashover in an 8877 can be due to loss of vacuum or due to loose
gold meltballs. The Joe Funderberg (W6IHA) test will detect loose gold
without opening the envelope.
http://www.somis.org/Goldmeltballs.html
>
> 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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>
>
>
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>
Richard L. Measures, AG6K, 805.386.3734. www.somis.org
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