Technics ST-03C

[Hellmuth]

The so called AM Syntheziser part in this Tuner does not work correct.
when i use the Rxfreq. 549kHz - the LO moves to 1,4MHz (instead of nearly 1 MHz); What i found out is. that the varicapvoltage starts with +4Volts ( 522KHz) and jumping !! somtimes up to 15 or 18 Volts; But with an extern Pwr Supply the AM VCO tunes correctly from 2volts (RXfreq 522KHz) up to 15Volts ( rx freq 1600kHz) When i am using a seperate Rf generator with an output frequency at nearly 1,4 MHz , feed this one into the MN6045E - i found with the display set to 549KHz at the outputpin (3) at the MN6045E the he will indicates nearly a phase/ freq. comparement.

Is there any gentleman who could help ?
my Idea should be - the MN6045E must have a not known mistake
because the FM ( vhf) part works correctly
And I do not have any circuitdiagramm of these Tuner and I do not know the correct function of these MN6045E ( no datasheet available)