СХЕМЫ И ДОКУМЕНТАЦИЯ

Модификация трансивера ICOM-756



Модификация трансивера ICOM-756

Сергей Матвеев (UA1OSM)
ua1osm (at) archangel.ru

Посети сайт www.mods.dk

Модификация гетеродинного фильтра трансивера ICOM-765, выполненная радиолюбителем SM0EBP, Боргом.

Subject: Re: IC-765 mods

Hello agn, Serge!

Let's se how it works this way!
Here is my text from 1989:
The IC 765 is a fine radio. Unfortunately we miss the old fine
passband-tuning.
IF-shift of course is also nice; but PBT better.
How abt getting both!?
Here comes a little easy mod that will give u IF-shift when the
IF-shift-button is IN and PBT when it is OUT!
You have to get to the PC-board at the underside of the radio.


Locate the brown wire going to base of Q38, cut that lead and insert a diode
in series.


Locate the multi-connector J31, cut the orange lead and connect a diode from
the coming lead to the same point as the one above (both diode-cathodes
together).
THAT's ALL!
Best of luck/73
Boerge/SMOEBP

I also enclose two small JPG.illustrations, I hope you can read them!?
This modification is very worthwhile. The diodes can be any low-level
SI-diodes.
>What rig do you have now? Why did you part with 765?
I had the 781 after the 765, liked it very much; but now have the IC 756 as
my base-station. It's OK and SMALL!!

>I consider 765 as best ever met rig, and thoroughly thinking of, refused to
>take 775, for I dislike it's design very much.

Same here - i think the 765 is a VERY good radio - I didn't like the 775
either!

>Still I have found in 765 some weak points; one of them is lack of PBT;

This u now can fix!!

The other weak point is VCO
>trimmers, if the air around has too much of sulfur, the upper VCO trimmers
>often go bad, due to lack of gold in contacts. I experienced such a problem
>both in 765 and 751.

You are rite - this trimmers are no good - we have the same problems here in
CLEAN Sweden -also on the IC 735, e.g.!!

I am born OZ - 1931, but moved to SM in 1967.TNX fer pix.
73's
Boerge