148 GTL Malaysia interesting mod

[Eskimo_Pie]

I have a 148 GTL that the previous owner did the HI/LOW BRT/DIM switches mod as well as adding 2 crystals, switched by the NB/ANL NB OFF switch. One is 11.1755 mhz and the other 11.0258 mhz. I have no idea where these crystals pull the radio to. Any ideas? THanks!!

[Eskimo_Pie]

Did some research and found the info in another one of my threads.....D'OH!!!!

The 11.1755 pulls the radio down for 40 below ch1.

Not sure where the 11.0258 goes

[PA629]

Are you positive that it's 11.0258 and not 11.3258? The 11.3258 is the usual xtal used with the 8719 chassis to go from 26.815 to 28.045.

[Eskimo_Pie]

Are you positive that it's 11.0258 and not 11.3258? The 11.3258 is the usual xtal used with the 8719 chassis to go from 26.815 to 28.045.

I'll have to crack open the radio again to be sure. Wouldn't the switch have 3 crystals? I have normal 40ch CB frequencies when the switch is in the NB/ANL position. I'll take some photos of the MOD to see if anyone else has done something similar. Thanks for the reply.

Greg

[Sporty Mike]

I have a 142 gtl that has the upper and lowers on the NB/ANL and the CB/PA switches. I don't use them because I have no idea where I'm at, I'm going to get an inline Dosy Freq. counter to solve that problem.


Mike

[Eskimo_Pie]

I have a 142 gtl that has the upper and lowers on the NB/ANL and the CB/PA switches. I don't use them because I have no idea where I'm at, I'm going to get an inline Dosy Freq. counter to solve that problem.


Mike

If I recall, the NB/ANL and CB/PA control two pins on the PLL chip. Do a a Google search, or search on this wonderful site, (I've learned TONS!!) for MB8719 MOD or 8719 MOD and you can find what channels you have. One position of the switches gives you 27.605mhz to 28.045 on ch 1-40, another position 27.445mhz to 27.725mhz on ch 15-40, and lastly, 26.815mhz to 27.005 on chs 15-40. The "A" will be skipped If I am not correct, someone please jump in and let me know.

73's

Greg

[TheCBDoctor]

Hi Eskimo_Pie

The 11.1758 will provide 40 channels below CB 1. The 11.3258 is the normal loop crystal with pin 10 on PLL MB 8719 lifted from ground. Using an 11.4758 for the loop crystal is for 40 channels above CB 40.

By using these 3 Crystal you will get a seamless frequency range of 26.515 MHz to 27.855 MHz. You can ground Pin 10 and Pin 11 using a MB 8719 PLL for additional frequencies. Do Not Do Ground Pin 10 on a MB 8734 PLL.

You will still have skips on the "A" Channels unless you mod Pin 16 with a 4.7K ohm resistor by cutting the trace and placing the resistor in its place, then simply apply zero or 8 votes to go higher or lower by 1 Channel. Use a 3 position toggle switch with a center off for normal operation.

If the radio is a Cobra 142 GTL, you will find a loop crystal of 11.1125 with pin 10 on the PLL MB 8719 grounded. Lift the ground and use an 11.3258 MHZ loop crystal.

Respectfully,

[Eskimo_Pie]

Hi Eskimo_Pie

The 11.1758 will provide 40 channels below CB 1. The 11.3258 is the normal loop crystal with pin 10 on PLL MB 8719 lifted from ground. Using an 11.4758 for the loop crystal is for 40 channels above CB 40.

By using these 3 Crystal you will get a seamless frequency range of 26.515 MHz to 27.855 MHz. You can ground Pin 10 and Pin 11 using a MB 8719 PLL for additional frequencies. Do Not Do Ground Pin 10 on a MB 8734 PLL.

You will still have skips on the "A" Channels unless you mod Pin 16 with a 4.7K ohm resistor by cutting the trace and placing the resistor in its place, then simply apply zero or 8 votes to go higher or lower by 1 Channel. Use a 3 position toggle switch with a center off for normal operation.

If the radio is a Cobra 142 GTL, you will find a loop crystal of 11.1125 with pin 10 on the PLL MB 8719 grounded. Lift the ground and use an 11.3258 MHZ loop crystal.

Respectfully,

Thanks again and again and once again for your help!! How can I identify Pin-1 on the 8719's? Is pin one (1) the top/left pin? If I am looking at the printed info on the chip upright, is pin one (1) the top left one, closest to the little indentiation on the left of the chip?

[Eskimo_Pie]

Well, I opened it up again and verified that the 2 xtals are deff 11.1755 (with markings on it of "148 GTL, FM 9818") and the other is 11.0258 (with a single marking on it of "SUNNY"). The stock 11.325 xtal is still in the original location.

To recap, BRITE/DIM and HI/LO do switch pins on the 8719. See photos:
[ external image ]
[ external image ]
[ external image ]

The number on the main board is "EPT014811Z" and it does have a Fujitsu 8719. Any ideas?