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Re: Question about Ameritron AL-1200 Amp (Uses one 3CX1200Z7 tube)

 

The Step Start relay arc is normal.? They all do it when the start is on an AC cycle peak or close to it.


-----Original Message-----
From: DupyRail <andymueller@...>
To: ham-amplifiers <[email protected]>
Sent: Tue, Jan 28, 2020 3:02 am
Subject: Re: [ham-amplifiers] Question about Ameritron AL-1200 Amp (Uses one 3CX1200Z7 tube)

FWIW, keep one hand in your pocket while doodling with it.

Andy? K9ATX



On 1/27/2020 10:49 PM, Cliff Fox (KU4GW) wrote:
No, not yet Alek, I'm planning on taking the cover off it tomorrow afternoon. One guy in Idaho told me the step-start relay may be the culprit or it could need the electrolytic caps replaced. If I could see the arc it would be very helpful, but I'm reluctant to turn it on without the cover on it, it may kill me! Maybe I can hear it, P.J. told me what it was doing when he brought it here, but I haven't hooked it up yet. The guy in Idaho told me the step-start relay in on the left side at the back so if I can hear it arc back in that area then maybe P.J. should order a new relay from Ameritron. Hopefuly I'll find a sign of the arc like a burnt or discolored resistor or a leaky capacitor, something I can see.?Thanks for your reply!

Very /73 de Cliff


On Mon, Jan 27, 2020 at 8:56 PM Alek Petkovic <vk6apk@...> wrote:
Have you determined where the arc might be? Bandswitch, RF deck, power supply, power switch, transformer, filter caps, etc?
73, Alek. VK6APK
On 28/01/2020 8:05 am, Cliff Fox (KU4GW) wrote:
I have a Ameritron AL-1200 brought to me by the KN4UNA, P.J., who received the amp from his uncle's estate (W4WWF Dale Mash SK) and it has a problem with giving a arc when the power switch is first turned on. The amp runs fine after that initial arc. Can anyone offer any advice on what I should check that may be the cause? I own a AL-80B and I know it has a inrush current step-start circuit in it to prevent a surge, but know nothing about the AL-1200. Does it have inrush current protection or a step-start circuit? I had a issue with my AL-80B a while back arcing from the tube parasitic resistors to the shaft going to the band switch. I wrapped the shaft in heat shrink tubing and that solved that problem. What should I check first in the AL-1200, perhaps a current limiting resistor? The amp is as clean as a pin and looks like brand new! Thanks in advance and very 73!?

Cliff, KU4GW 

-- 
"Where the Old Soo crossed the New Soo"
Duplainville, Wisconsin

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