my idea came that I was looking schematic of Midland 1001 Z CB radio, and I have noticed, they use same crystal for 2nd L.O. and for PLL reference freq. by adding another crystal OSC circuit of same frequency for 2nd L.O. and changing only PLL ref crystal, it may be possible to move up from CB freq. to 10 mtr or move down to 12 or even 15 mtr band. of cause they require retuning and possibly changing parts of front end, amplifier stages, final amp, low pass filter, etc. it is just my thought of conversion, I have not done it, it is just idea.
That is not necessarily true. Quite often by simply changing the PLL reference oscillator, especially in modern day 11 meter transceivers, can result in the PLL's "PD" (Phase Detector), setting the PLL to "Unlock". This will result in no receive and no transmit.
What PLL chip is in the Midland 1001Z transceiver? I suspect the PLL chip in the Midland 1001Z transceiver is one that will not allow you to modify the transceiver for operation on 10 meters.
Modern PLL chips have circuitry that prevents changes to be made that results in operation on "illegal" frequencies outside of the normal 11 meter band. When changes are made to the modern PLL circuit, the PD (Phase Detector) detects the "illegal" frequency error and the PD unit of the PLL circuit sets up the "unlock" state then turns the VCO (Voltage Control Oscillator) "OFF" that results in no transmit and no receive. I doubt you will be able to modify the Midland 1001Z transceiver to operate on 10 or any other ham band.
The term "illegal" refers operation on frequencies "outside" of or any frequency not determined to be a "legal" channel frequency in the 11 meter channel frequencies, 1 to 40. As far as the PLL is concerned, any frequency that does not fall within the normal 11 meter channelization, channels 1 to 40, is "illegal" so the PLL chip through the operation of the PD circuit, shuts the transceiver down, again, no transmit and no receive.
One more thing. Simply changing a PLL chips reference oscillator can and will affect the local oscillator IF injection frequency which can lead to loss of receive as well as transmit. Simply adjusting the IF transformers thinking this will "compensate" for local oscillator IF frequency error, will not work. There is more to a PLL reference crystal than meets the eye.