[1000mp] delayed display turn on

Sat, 19 Jul 2003 08:57:26 -0700

Hi,

        Re:   Yaesu 1000MP display

The details provided by Leo relating to the display suggests the
reason for the slow or blank display.
The description by Mike Gilmer N2MG states that there is a
"...thermal fuse..". Possibly this thermal fuse is not a fuse,
rather
it is an NTC thermistor. This will explain the slow start up.
When
cold (room temperature), the thermistor will have higher
resistance,
limit the inrush current and the display will be dim.
As it warms up, the resistance drops, current increases and the
display
is bright. If indeed it is a thermistor (??), replacing it with a
piece of
wire may not be a good idea. There will be no inrush current
limit!
As the saying goes, "if it is not broke, don't fix it". So, I
don't like
the idea opening my 1000MP and poke in.
Possibly, someone who is working on the radio, can measure the
room temperature resistance of the 'thermal fuse' and the current
profile. If it is a thermistor it is possible to replace it with
similar unit
but higher ratings. The effect may be slower turn on of the
display.
Another possibility is that the device is a resettable solid
state fuse.
My vote is that the device is a thermistor.

If someone has a non functional inverter board, I would like to
have
it and try to figure out the details.

Thank you

73,

Mort, KB6BSN

----- Original Message -----
From: "Aur�lio da Costa" <[email protected]>
To: <[email protected]>
Sent: Saturday, July 19, 2003 2:43 AM
Subject: Re: [1000mp] delayed display turn on

> The problem is that eventually the display does not come up at
all. There is
> a mod to take care of that. You can find more details on this
web page:
> http://mailman.qth.net/pipermail/1000mp/2002-August/003516.html
> Mine is showing the same symptoms and is taking more and more
time for the
> display to turn on.
> 73, Leo CT1CSN
>
> ----- Original Message -----
> From: <[email protected]>
> To: <[email protected]>; <[email protected]>
> Sent: Friday, July 18, 2003 9:32 PM
> Subject: Re: [1000mp] delayed display turn on
>
>
> > Ron, W8GUS wrote:
> >
> > "...last week I went on vacation..... After my return, when I
turned on
> > the radio, for the first time ever the display was blank for
a few
> > seconds. Then the radio worked normally.
> > ==========
> > The problem of delayed turn on of the display appears to me
to be
> > directly related to how long the radio has been turned off.
At times I
> > may not use my MP for a week or more and when I power it up I
might have
> > to wait as long as 5 seconds for the display to light up.  If
only
> > powered down overnight, the display comes on immediately the
next
> > morning.
> >
> > It does not seem to be related to whether the antenna is
connected to the
> > radio or not because during those extended periods of power
off the
> > antenna is connected to a different radio (and not to the
MP).
> >
> > I'm not at all concerned about this and just write it off as
one of those
> > nuisance things.
> >
> > 73, de Earl, K6SE
> > _______________________________________________
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