Minitor II refreq. question

Dispatcher85 · Post by **Dispatcher85** » Thu Sep 30, 2004 7:59 pm

I was wondering how hard it is to refreq a minitor II. I have a couple that need to be changed and I would like to do it myslef instead of sending it out. Thanks...Corey

Hoseman292 · Post by **Hoseman292** » Thu Sep 30, 2004 8:14 pm

I've changed out the crystals on a few Minitor II pagers. I went from 154.010 to 154.160 without any alignment and the reciever is pretty sensitive.

If I recall correctly, the crystal is on a small board held in place by a few tiny screws. You remove the board so you can de-solder the old crystal and solder in the new one. Pretty easy to work on. I never had any problems.

Hope this helps.
Tim
N3WIR
Silver Spring Maryland

Dispatcher85 · Post by **Dispatcher85** » Thu Sep 30, 2004 10:06 pm

Did you ever do any that went with a wider freq change like say 154-165 mhz. I have never done alignment either.

firetech792 · Post by **firetech792** » Fri Oct 01, 2004 3:23 am

The MII models come in sub bands. You probably won't be able to get your pager to receive in 165 MHZ if its now set up on 154 MHZ.
Here are the Minitor II sub bands:
132-139.99 Mhz
140-147.99
148-159.99
160-174.00

You might get lucky. It might receive but at a reduced sensitivity. But I doubt it. Thats a pretty big change.

Good luck
firetech792

Fri Oct 01, 2004 3:41 am

Well, to align the pager, you will require both a service mon itor and a "shoe" to place the pager in allowing for consistent parameters to align it by. (The factory ones are quite expensive, but I have a home brew that I made for about $20.00) I would STRONGLY reccomend having a pager aligned after any crystal change, but,as has been stated, you can generally get away with changing within a 1/2 a meg and not having to do so. More than that, and it's a must do.

The crystal it's self is located on the RF board. It is the smaller board attached to the main board and is held in by a plastic clip on one side and a male/female circut connector on the other. Be sure to remove the antenna from the board before removing it. As for the crystal, it is soldered in, but if you have a pair of crystals on the board, make sure you are changing the right one. Most shops will charge about $35.00 or so to change the crystal (if you already have the crystal you want to use) and align the unit and I would reccomend going this route as it is cheaper than having to send it out for repair if you damage it due to being unfamiliar with what is involved.