[Yaesu] FT-2600M Memory Loss
Patrick A. Thompson Sr.
[email protected]
2002年8月11日 00:50:08 -0400
I looked again at my notes from my last unsuccessful try at
fixing the memory problem. One thing I noticed this time because
of your reference to the Azden problem was Q1030 a M51951 three
legged thing that I assumed was a regulator.
It turns out the M51951 isn't a regulator at all but a "voltage
detecting, system resetting IC".
see http://doc.what-trend.com.tw/pdf/14560.pdf
It also turns out there is a Schmitt trigger internal to this chip.
The input to the M51951 is set by R1171 and R1340 as a voltage
divider both 4.7k.
I'm considering changing this ratio so the chip causes a CPU
power down at a higher voltage. I think I should also move the
extra caps I added to the output of Q1028 to the input pin. Q1028
is a three legged 5 volt regulator.
Of course I could quit while its still working ;-)
Thank you...
WA4TUK
> > -----Original Message-----
> > From: [email protected] [mailto:[email protected]]
> > Sent: Saturday, August 10, 2002 11:00 AM
> > To: [email protected]
> > Subject: Re: [Yaesu] FT-2600M Memory Loss
> >
> >
> > While this may not have any bearing on your problem, the Azden PCS-4000
> > initially came out with the same problem. The cause in that
> case was the
> > input voltage. When it decayed slowly, the set was unable to determine
> > that the micro should be placed into the "sleep" mode. If the switch on
> > the set was opened instead, there was a sudden drop in voltage and this
> > could be detected and the micro placed in the proper mode. Azden had to
> > add an additional transistor to act as a schmitt trigger to the line
> > going to the micro. This cure the problem.
> >
>