PRO433 Completed discriminator output

[kd5dga]

I had asked for this a few times in the past about a discriminator output for the PRO433. I just completed mine a hour ago and works fine.
I started here for the information on what IC to possibly look for;
http://www.discriminator.nl/index-en.html
I had found that the PRO433 uses a SL5018 low power narrow band if ic.
http://www.discriminator.nl/ic/sl5018.pdf
The output is on pin 9 of that ic. However if you turn the scanner over, bottom side showing up, you will see a test point called LND4 FM det. This is hooked to pin 9 of the SL5018. I used a sheilded thin cable and hooked to this point (soldered)then to a 10k 1/4 watt resistor to the center pin hook up of a 1/8 inch mono socket on the back side of my radio.

Works great.

 

[KD4YGG]

Thanks for taking up this challenge and sharing with us.

 

[ka3jjz]

This question is quite liable to show up again - this should go into the wiki, including a shot of the tap point, if possible. Good job! 73s Mike

 

[kd5dga]

I would have took pictures but my digital camera went down over Christmas.
Heck taking up the chalange was nothing but pure research on the parts.
I wanted to do this since I am weary of my old PRO92 going dead.
Now since I did borrow some information from the website mentioned in my first message and used a 10k value for ther resistor there maybe a substitution with a lessor value like 1k ohms or so fourth. The output is exactly the same as my PRO92 when it come to volume.
Go ahead and post it to the WIKI reference page.I dont know how to do it.

 

[kd5dga]

I had finally put together some information on a discriminator output for the PRO433.
1. since there is no information directly relating to the PRO433 for modifications I had to do a little reading;
http://www.discriminator.nl/index-en.html
2. I opened both upper and lower radio case halves.
3. Looking I had found an IC SL5018 (IC numbered 3) which is a low powered narrowband fm IF IC.pin 9 is the connection point.
http://www.discriminator.nl/ic/sl5018.pdf
4. looking at the printed circuit board with bottom side facing up there will be a test point called LND4 FM disc.
5. solder a shielded cable to this point and run the cable to the back of the case. I had to snake mine around the side of the pc board to the top side where there is room to put a 1/8 inch mono socket on the back of the radio.
6. drill hole for 1/8 inch mono socket. (Radio Shack brand)
7. solder a 10k ohm resistor to the center pin connection of the socket and to the center cable of the discriminator output wire from LND4.
8. reassemble radio and enjoy!

73’s
Glenn Blum
kd5dga