[1000mp] Very Hot Final Heatsinks

[William Shadid]

Norm,

Hans is correct. I long ago learned this with my Mark V -- leave the power
level at maximum on Class A. I note a higher temperature level in Class A
but nothing like what I hear about on the reflectors. Up to now I had
thought this to be a problem with selected radios -- but Hans' note gets me
to thinking that it is really a lack of understanding with the radio. Yaesu
should be more clear about this -- but they certainly do not have an edge on
things omitted from the manual!!

I drive an older Drake L-7 with my Mark V and use the Class A selection
simply to keep my drive power low. I do not use Class A when I run PSK.
While I don't often run the amplifier, I can say that I note only somewhat
higher heat sink temperatures. The fins are far cooler than running older
domestic, solid state radios such as an old Cubic Astro 103 with its large
rear heat sink. They are also much cooler than the single heat sink on my
Ten-Tec Omni VI+ after a long operating session. If you are experiencing
"scalding" temperatures at 75 watts output, Class A, I would say that a call
to Yaesu is in order.

73,

-Bill, WA9MXQ


----- Original Message ----- 
From: "Hans Remeeus" <hans at remeeus.nl>
To: "All about Yaesu 1000mp" <1000mp at mailman.qth.net>
Sent: Monday, November 28, 2005 11:54 AM
Subject: Re: [1000mp] Very Hot Final Heatsinks


When you run Class-A and decrease your power output from 75 Watts to
20-25 Watts this will cause an extensive amount of extra heat.

Be extra careful using Class-A and don't decrease your power output when
using Class-A!

The finals of my Mark-V (200) were blown out during a Class-A
SSB-transmissions decreased from 75 to about 25 Watts.

73,
Hans Remeeus (PA1HR)
http://www.remeeus.nl
Communication is about people, the rest is technology.




Norm Bryant schreef:
> I purchased a new Yeasu FT-1000MP Mark-V in February of this year. The
> radio has seen almost ten months of service. The final heatsinks have
> always seemed to run extraordinarily hot but, just recently, I began using
> PSK-31 mode. After a normal on/off QSO that went for approximately ten
> minutes during which the cooling fan came on almost immediately, I
> measured a heatsink temperature of 143 degrees on the second heatsink from
> the outside. This is too hot to touch, and seems to me to be way out of
> line with safe operating parameters. The Yaesu technical folks said they
> do 'get a little toasty', but that has done little to convince me that
> this radio is operating safely. In PSK, I'm usually running about 20-25
> watts out. I always stay on top of the SWR with both the built in meter
> and a secondary meter. Cooling fan comes on within 30 seconds of beginning
> a transmission. Output is solid, and signal reports are good. But, as far
> as I'm concerned, anything that gets this hot should have been labeled
> with a 'caution' warning.
>
> Is this a normal operation parameter for the 1000MP?
>
> Thanks,
> Norm
>
>
>

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