Where is P3 located at on the cabinet door?
I'm trying to interface a external controller. The Motorola bulletin says locate J3/P3. J3 is the service handset and only has 8 pin, but the instructions want the connections to pins 9 and 14.
Thanks for any help on this
Tim
Motorola R100 P3 location
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tskilbride
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Re: Motorola R100 P3 location
They are talking about the J/P3 connector on the QRN4314A interface board.
You pretty much must have a main control board attached to bottom of the "lid" of the radio cabinet.
The QRN4314A interface plugs into that main control board "piggy back" style, plugging into a couple pins of a white connector.
There is another plug of wires that are "hardwired" to the main board.
And the J/P3 connector is the third connector going from the piggy back board to the DB25 on the side of the cabinet.
This QRN4314A board is about an inch and a half wide, and about four inches long.
Depending on what options the radio was purchased with, you might not even have one.
You pretty much must have a main control board attached to bottom of the "lid" of the radio cabinet.
The QRN4314A interface plugs into that main control board "piggy back" style, plugging into a couple pins of a white connector.
There is another plug of wires that are "hardwired" to the main board.
And the J/P3 connector is the third connector going from the piggy back board to the DB25 on the side of the cabinet.
This QRN4314A board is about an inch and a half wide, and about four inches long.
Depending on what options the radio was purchased with, you might not even have one.
Steve K.
Re: Motorola R100 P3 location
Right many R100's did not have the option interface board and the DB25 connector on the chassis.
You can interface by going direct to points on the large board in the cabinet lid.
You can interface by going direct to points on the large board in the cabinet lid.
Re: Motorola R100 P3 location
Where can I find where these locations are? I just brought one down into the ham bands and had to replace the tuning screws with brass screws to get it to play quite nicly in the uhf ham bands. I am not trying to high jack this thread. I am just trying to figure out where to get flat audio from the r100 receiver. I have found discriminator audio but not flat audio.
Re: Motorola R100 P3 location
Are you sure you have an R-100?
There are slugs in the R-100 coils, Maxtrac based radios are the ones that people typically use brass slugs.
And I have never had a problem tuning the R-100 down into the 440 range.
As for "flat audio" that depends on which way you define flat.
Discriminator audio is flat in that it has not been processed ( de-emp ) in the receiver.
So, it is still pre-emphasized as it was when transmitted by the originating radio.
But that is the flat RX audio to me.
Let us know for sure what radio we have, and it is pretty likely that we can find you the connections you need.
There are slugs in the R-100 coils, Maxtrac based radios are the ones that people typically use brass slugs.
And I have never had a problem tuning the R-100 down into the 440 range.
As for "flat audio" that depends on which way you define flat.
Discriminator audio is flat in that it has not been processed ( de-emp ) in the receiver.
So, it is still pre-emphasized as it was when transmitted by the originating radio.
But that is the flat RX audio to me.
Let us know for sure what radio we have, and it is pretty likely that we can find you the connections you need.
Steve K.
Re: Motorola R100 P3 location
If he has the older R100 that has the trimmer capacitor in the VCO, the trimmer capacitors fail from getting tarnished. They usually fail open so he would need a brass slug in the VCO coil.