[Yaesu] Re: Pin Diodes FT-990

[Stuart Rumley]

John-

This IF hiss in the FT-990s has been something I've been interested in
working on for some time.   I haven't had the time to dig into it up until
now.  There are a number of places in the IF and AF circuits that I think
are contributing to this problem.   What I would like to propose is that if
you or someone else has an FT-990 that I can use to evaluate this problem I
will fix the problem and make the mod available to the newsgroup.   Of
course I would return the loaned radio and I would also need someone to
supply an extender card as well.  Kind of provocative but maybe we can make
this otherwise good radio close to perfect.

Stuart


----- Original Message -----
From: "John Bolduc" <hydro@fx2.com>
To: <yaesu@mailman.qth.net>
Sent: Monday, February 11, 2002 2:49 PM
Subject: Re: [Yaesu] Re: Pin Diodes FT-990


| Hi all
|      I have a 990 that I did the pin diode mod too..... My best advice
It's
| a waste of time. I notice no difference. & I am a Tech. The biggest mod
you
| could do to the 990 & 1000MP is fix the IF hiss coming out of the 455khz
| notch circuit !!! Both those radio have the exact same 455 IF circuit
using
| bipolar transistors and the same Hiss !!!!   I'm trying to fix mine and
come
| up with a circuit mod....... And it not just my rig I have many friend who
| have the 990 & they all are hiss box's !!!!!!!!!  So are the MP's it just
| Mask by the DSP filters
|
| 73's john KI4NR
|
|
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