[Amps] Macaw PRM-1

[Martin Sole]

Hi Alek,

Only 2 devices? I'd think it would be hardly complex so drawing the
schematic from the physical unit would not be too difficult, and useful for
reference. Just the job for one of your frozen nights over a hot cocoa!
Stick it the files section mate then we can all have a gander.

Martin


-----Original Message-----
From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
Behalf Of Alek Petkovic
Sent: 07 September 2010 13:37
To: amps at contesting.com
Subject: [Amps] Macaw PRM-1

I have a Macaw PRM-1 peak reading power/swr meter. From looking through the
archives on this list, I see that others have been looking for manuals or
schematics for this  meter.

It seems that this unit has a commonly occurring fault. Namely, when set to
peak reading mode, the meter moves hard over to the full scale position.
Mine had the same symptoms.

There are two active devices in the meter. A 2SK117 mosfet and a 741 op amp.
To clear the full scale fault, you simply need to change both devices. I
just did it with my unit and I'm very pleased to have the meter working as
it should. You don't need the schematic.

73, Alek
VK6APK

PS: I have 9 spare 2SK117's. If anyone else has the same problem, let me
know and I'll post one to you.




http://www.qrz.com/db/vk6apk
http://www.qrz.com/db/vk6ap


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