On Aug 14, 2005, at 7:46 AM, <k5go@cox.net> wrote:
> 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?
At a minimum, you need to install a glitch-R in the +HV.
>
> I learned a good, inexpensive lesson and will not try a used tube
> again without prior testing.
Stan -- I would wager a medium pizza with 4-toppings that the used
tube is not defective.
>
> 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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>
>
Richard L. Measures, AG6K, 805.386.3734. www.somis.org
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