Tracy,
I am replying directly and also reflecting the message on the new list.
If anyone wants to reply to Tracy, please send plain text directly to his email
address as I am uncertain of his email receiving ability. Also, please CC the list
so others can see your reply.
To bring the rest of you up to date, here is the original mailing from him, and
then my reply.
Kevin,
I see you have a lot of knowledge on Micor's and wonder if you
could help me?
Do you know of anywhere one might be able to obtain a manual which
explains the 'card controller rack' and backplane logic? Which manual #
this is? I've got a vhf micor mobile manual which appears to take care of the
receiver, exciter and pa questions... But the card rack is still a mystery.
Any help would be greatly appreciated.
Thanks,
Tracy,
K0DOE
Tracy,
Does the backplane board have a model # on it anywhere?
How about the cabinet? any numbers will help determine this.
Is it a Unified Chassis or does it have a big 50 conductor ribbon
cable connecting the backplane to the rx and tx, (non unified)?
The model # for the Control & Applications manual MAY be
68P81025E60-C
Don't let the card rack and backplane intimidate you. For all
practical purposes (in ham use) it can be bypassed.
What cards are installed into the rack?
Kevin
This next part I just received and I am replying to him and the list.
My reply is threaded below.
Acsdsupt@... wrote:
The model # is scratched out from moving it. It does have a big 50 conductor
ribbon cable (mylar) connecting the backplane to the rx and tx!
You have a "non-unified" chassis.
I got the receiver to tune up however, not quite to the sensitivity that I am
accustomed with GE! Only blows about .5 Microvolts @ 12 dB SINAD. I'd heard
that one needs to add length to the bolts in the helical in order to get them
to tune all the way down? Do you know if this is true?
I have a different solution to this problem. My solution does not compromise the
front end selectivity like when using longer tuning screws. Go to
and
for explanation of this solution. Also
the coils are now on sale from me if you choose to purchase them.
The exciter tuned up too. Although I had to dive into the schematics for a while
to figure out where to "test" the test points since I don't have a service box.
I just used a digital vom instead.
A simple 50 uA meter works fine.
Seems to work. But I can't get the crystal tune on frequency. It's high! The
crystal (147.165 MHz) will only
warp down to 147.166.4. I'm going to try sticking a 1-20 pF cap in parallel with
the varicap and see if I can get more range. (BTW, Didn't work in parallel with
the varicap but tried this with a 1 pF across the bottom of the
crystal and it worked! Right on frequency! Hot Darn!)
Your exciter must use elements with 4 pins, Correct? The 3 pin model (with K 1007A
element) is standard and does not have a modulator in it. This model utilizes
phase modulation. The 4 pin model (with KXN 1019 element) was originally designed
to transmit DPL (digital private line) and was a true fm exciter. I don't know why
the cap across the varactor did not work.
Lastly, this thing was configured as a remote base for a business. It has a
Squelch Gate Card, Line Driver Card, DC Transfer Card, Station Control Card
and TOT Card. Don't have a clue what some of these do except for the obvious.
Can't seem to get it to repeat with opening the squelch. Something is muting
the receiver when I push to manual tx key on the Station Card. So close but
yet so far! Any ideas?
Thanks!
Tracy
Yea, lots of ideas....
Are you going to use an outboard controller with this station? If so refer to
for information. If not, refer to and
ignore the rest.
On the first conversion, since your station is a NON UNI chassis, some things are
going to need to be translated. Read the information and try to understand the
CONCEPT, don't try to convert yours using the information. Basically to keep the
receiver from muting and to eliminate the need for the line driver card. Pull the
line driver card out. Then, on the Remote Control Chassis, (the chassis where the
cards go in) jump pin 15 to 39 (where the 50 pin ribbon is attached). This allows
the preamp audio from the receiver audio and squelch board to be fed into the
volume control to provide amplified receiver audio to drive a local speaker with
no muting action. My personal notes also show modification to the Audio & Squelch
board. My notes show to cut off the trace leading to IC 202 pin 14. Also cut trace
leading from the intersection of IC 202 pin 13 and C235 (a .22 uF) and the long
pins leading to the outside world. If anything is allowed to input to pin 13 on
the A&S board (except for having the .22 uF cap connected) will totally mess up
the action of this board.
Bottom line is to eliminate as many of the cards as possible. I do not care for
the way the Squelch Gate card manages the squelch action, or anything else it does
(I eliminate it because I use external controllers) . This concept is outlined in
the Station Modification listed above.
If you have trouble cross referencing the modification to the non uni chassis
email again and I will take the time to do it.
Hope this helps,
Kevin
