Uniden Washington (MB9719) Channel Mod

[David Waits]

Extra channels Washington(Uniden w/8719 chip)
1.) Remove crystal X4(11.1125). Install 11.3258 crystal.
2.)Realign Xmit to reset freq. USB(CT-3)27.2075,LSB(L19) 27.2025,AM(L20) 27.2050
3.)Locate pin 10 of 8719 PLL and cut trace on both sides of pin 10 to isolate it from ground.
4.) Solder one side of switch 2 to cut by pin 10 and other side to board ground on other side of pin 10.
5.)Solder wires of Switch #1 to traces on pin 11 and pin 12.
6.) Cut trace by pin 14 and jump with 4.7k,1/4watt resistor.
Solder one side of switch#3 to pin 14 side of trace and solder other side to pin 9 .

If you need to unlock and stabilize the freq. drift on the Clarifier let me know.

All for educational uses only!

 

[Harley3315]

This is the conversion I do with the Uniden Washingtons and Cobra 142GTL's. I don't swap out the 11.1125 mhz crystal, it's not necessary. I just leave it in the radio and utilize the 11.1125 crystal.

I use this switch configuration as shown for my channels. This setup will get you 192 channel capability, (26.175-28.085) with no skips other than the usual "A" channels.

Both toggles must be double throw, center off. I illustrated a DPDT center off and a SPDT center off, but you can use DPDT center offs for both, don't matter.

Make sure you do the resistor mod on pin 14 that Unit 399 illustrated in a previous post to get your bank of 4 channels (26.775-26.805, 27.415-27.445, 28.055-28.085).

Hope this helps!


~Cheers~

The pic isn't showing can you post it again?

 

[Harley3315]

Extra channels Washington(Uniden w/8719 chip)
1.) Remove crystal X4(11.1125). Install 11.3258 crystal.
2.)Realign Xmit to reset freq. USB(CT-3)27.2075,LSB(L19) 27.2025,AM(L20) 27.2050
3.)Locate pin 10 of 8719 PLL and cut trace on both sides of pin 10 to isolate it from ground.
4.) Solder one side of switch 2 to cut by pin 10 and other side to board ground on other side of pin 10.
5.)Solder wires of Switch #1 to traces on pin 11 and pin 12.
6.) Cut trace by pin 14 and jump with 4.7k,1/4watt resistor.
Solder one side of switch#3 to pin 14 side of trace and solder other side to pin 9 .

If you need to unlock and stabilize the freq. drift on the Clarifier let me know.

All for educational uses only!

could use help getting it to settle in. The jumper and cap on pin 9 trace side need to be there still?

 

[Enterprise312ok]

Extra channels Washington(Uniden w/8719 chip)
1.) Remove crystal X4(11.1125). Install 11.3258 crystal.
2.)Realign Xmit to reset freq. USB(CT-3)27.2075,LSB(L19) 27.2025,AM(L20) 27.2050
3.)Locate pin 10 of 8719 PLL and cut trace on both sides of pin 10 to isolate it from ground.
4.) Solder one side of switch 2 to cut by pin 10 and other side to board ground on other side of pin 10.
5.)Solder wires of Switch #1 to traces on pin 11 and pin 12.
6.) Cut trace by pin 14 and jump with 4.7k,1/4watt resistor.
Solder one side of switch#3 to pin 14 side of trace and solder other side to pin 9 .

If you need to unlock and stabilize the freq. drift on the Clarifier let me know.

All for educational uses only!

I need to know about stabalizing the clarifier. I have a freinds washington with two xtals added on the bottom of the board. The unlocked clarifier works fine at first but after warm up It can not be adjusted below 400 cycles above the proper freqency. Any help would be appreciated I have had this washington almost a week and would like to get it back to my friend

 

[brandon7861]

I have a washington that did something like that, but it went in the shed before I had a chance to look at it. If I remember right, when I extended some wires to move the channel mod switch, things started acting funny.

I wonder if the added wire caused the crystal to jump to one of its spurious frequencies. Did you make any wires longer?