Hi Brian !
There is a general problem with ALC circuits and some transceivers:
If your TX is capable of giving substantially more power than your
PA wants, the ALC/power adjustment circuits are often not fast enough
to avoid overdrive peaks at the beginning of syllables or cw "dits or
daahs".
You could try to send a string of cw "dits" with extra spacing between
them,-
this should normally also trip your circuit if this is the problem,- but not
always.
What confuses me is that you can transmit a couple of minutes before it
happens. It could be that your your PSU protection has a "sample- and hold"
circuit that triggers when it "thinks it has got enough of it".
As i do not know your amp,- I can not give you any specific advice as to a
mod.
Be aware that some transceivers actually use internal power adjustment
circuits
showing exactly the problem described above... even if you do not use
external ALC.
Peter
----- Original Message -----
From: "Brian Sarkisian, KG8CO" <cqkg8co@yahoo.com>
To: <amps@contesting.com>
Sent: Saturday, December 01, 2007 10:26 PM
Subject: [Amps] ALS-600 with ALS-600SPS SSB problem
>
> The problem I am having is that the power supply is kicking off while
> in SSB. I can key up the amp into a dummy load using RTTY and CW at
> about 400-500 watts out and the amp and power supply works fine.
>
> The amp is hooked to an FT-1000MP. I have the ALC hooked up and
> adjusted. I am running abt 50 watts in with about 400 watts out, and
> have been testing it on a dummy load .. so the SWR is flat. Mic gain
> has been minimized and processor turned off. The amp is wired for
> 120.
>
> But once I am on SSB and lets say have been chatting for a couple
> minutes, the amp and power supply will kick off. Looking at the
> meter on the switching power supply it looks like it is only pulling
> 5-8 amps when it kicks off.
>
> It seems to be a voice thing on SSB.
>
> I have read a couple reviews on E-ham with people having this same
> issue. I am hoping there is some sort of fix.
>
> I have spoken with Ameritron, and they didn't have much to say,
> though he did mention there is a SWR protection circuit and the power
> supply has an line voltage protection circuit. If there is NO fix
> per say, can the protection circuit in the power supply be disabled,
> and I will just take my chances.
>
>
>
>
> Thank you for your time.
>
> 73 de Brian, KG8CO
>
>
>
>
>
>
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