Batboard

I have an 800 MHz Maxtrac (D35MQA5GB5BK) that I want to use as a 902 MHz receiver. I also have a conventional EPROM that I can use to convert it to a conventional radio.
I need to review the process to do this.
Do I blank the radio first, then change the EPROM and re-initialize ?
The reason I need to make it conventional is to get the COR signal on the accessory plug which does not seem possible if its a trunking radio.
After that I can do the rest of the "surgery".

Thanks, Dick, W1KSZ

Assuming you are satisfied that the radio is working properly first, you do just as you said. (Assuming you have a radio that has the talkaround (Tx 851-870) VCO)

First blank the radio. Regular Maxtrac LAB will do this even if the radio is a trunking model.

Then change the firmware. Next reinitialize the radio as a conventional unit. You should go through the alignment section of the board replacement at this time. Since you are going to use it as a receiver - you can skip over the transmit settings, but getting the crystal data in will make the radio stay on frequency.

Last step is to do your conversion (change the front end filters) Makes a great repeater or link receiver.

Good luck.

Where do I find the Rosetta Stone that tells me which VCO I have ?

Thanks, Dick, W1KSZ

Your RF board should be an HLF9122 which has the talkaround VCO. Removing Q205 on this board is one way of causing the VCO to operate on the upper range at all times (which is where you want it so you get low side injection for the 902 band)

The other RF board - HLF4095 - usually does not have the talkaround capable VCO.

xmo wrote:Your RF board should be an HLF9122 which has the talkaround VCO. Removing Q205 on this board is one way of causing the VCO to operate on the upper range at all times (which is where you want it so you get low side injection for the 902 band)

OK, I've got one in front of me right now...

I don't have a manual, so I am hoping someone will take a photo of which transisor Q205 is for we who are manual-less.

Thank you!

there was a pic floating around, but cant find it..

but, if you look on the RF board , there is a glob of glue that has a cap and a transistor on it, thats the one you want (you have to remove a metal shield to get to the glop)

OK, for once and for all...

A or B?

Link doesn't work.

va3wxm wrote:Link doesn't work.

It should work now.

"B", and you can just cut the leg farthest away from you as you look at that picture. That is the collector. That way you can restore it if needed and you don't have to pull the board.

And I just pulled the MuRata filters and jumpered them.