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[Amps] Yaesu Quadra circuits wanted

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Subject: [Amps] Yaesu Quadra circuits wanted
From: "Mark Hill" <>
Date: Thu, 16 Oct 2008 10:03:57 +0100
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Does anyone have an electronic copy (or even a paper one, come to that!) of
the circuits / service manual for the Yaesu VL-1000 (Quadra) amplifier?

I have recently completed a PIC-based interface to allow my TS-2000 to
control the Quadra in a Internet Remote Base (IRB) application.  Now I can
power the amp. on and off remotely and the amp. tracks band changes made on
the TS-2000 TX.  Problem is, with the amp. having no control port, the
control-side runs a little blind (poke and hope!).  Pointing a web cam at
the amp.'s front panel works, but it's somewhat crude and chews up Internet
bandwidth.  If I had the circuits, then perhaps I might be able to extract a
few useful status signals from the CPU circuitry.

I would also like to investigate making the Quadra auto ATU work at lower
power levels.  The amp. will give full power out with around 40 W of drive
on most bands, but the auto ATU will not operate with much less than 100 W
of drive.  Connecting the ALC up might sort this, but I prefer just to give
the amp. the drive it needs and no more.

It's a pity that Yaesu have not refreshed the design of the Quadra in the
control department.  They must have lost quite a few sales to the SPE Expert
as a result.  For my money, the Quadra, old as it may be, is still the
better of the two as an RF tool.



Mark Hill - G4FPH
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