JC Penny Frequency Expansions


This is for radios that use the SM5104 PLL



The PLL is a binary type, to increase the radio up to 28.000 you just need to pull pin 8 high and pin 9 low, this will increase the frequency range by 128 channels (up to 28.245 on channel 1).

If this is too high you could just pull pin 10 high instead, this will increase the range by 64 channel and move the radio up to 27.605 on channel 1 through to 28.045 on channel 40.

If this is too low pull pin 11 high as well as pin10, this will give you and increase of 96 channels between channels 1 and 27, so it will cover 27.925 on channel 1 to 28.235.


To control a pin cut its track and add a 4.7 KOhm resistor across the cut.

So to pull a pin low cut its track and add a 4.7 KOhm resistor across the cut, then jumper (through a switch) the PLL pin to pin 16 (this is the ground pin), or to pull it high jumper to pin 1 (this is the + supply).


This counter shows the number of hits since the 28th February 2002


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