Changing region band on Nakamichi SR-40?

[filmis]

Hello,

I've got the Nakamichi SR-40, which is the Japanese variant of the SR-4. I've gotten everything to work except for one thing: the tuner is set to the Japanese broadcasting frequency range, which is 75-90MHz. There's only one station I can pick up in this range, and it's a Christian rock station. As enlightening as that may be, from time to time I imaginably will want to listen to something else!

I have managed to get the Toshiba TC1647BP chip to operate in the North American frequency range by setting pins E1 and E2 to high, where previously they were low. While I can search up and down the whole frequency range, the tuner stays permanently, and badly, tuned to a single station. I've followed the schematic and datasheet to the letter and I just can't seem to get this to work. VT stays at a constant 30.50V. I know I haven't done any damage because I can go back and switch it back to the Japanese range and it'll tune correctly then, with VT changing as it should.

Any ideas or suggestions?

 

[rcs16]

Little bit more to it than just the PLL LO VCO range, the RF tuned ckts have to center on the freq range in question, 88-108MHz and the LO has to have a range of 88-108MHz + 10.7MHz IF offset. It is a lot of work and requires you to understand the design completely, re-wind coil/transformers, not an easy job for a hobbyist.