Hi! Mr.Cacek ! Now after you switched your processor to our Euro FM band setting 87,5 Mhz , it ordered cx7925A to be waiting for 87.5+10.7=98.2 Mhz from the tuner oscillator. Then your CX7925 with the pump+filter circuit produces a voltage for the oscillator varicaps and the oscillator should make 98.2 Mhz and give that freq back to CX7925b. But this doesn't happen because the oscillator is still limited by Japanese band. I guess it makes very low frequency ( possibly 90-10.7=79.3 Mhz ) . The CX7925b receives wrong ( and low) frequency and following its own logic to increase voltage for varicaps it waits for right higher frequecy in return. In this stupid situation what it can do - is to send more higher and higher voltage untill it reachs a limit of 23Volts , still having no desirable frequency from the oscillator. Can you measure somehow your current oscillator frequency ? I remember - when I re-tuned my Technics st-g90 from Japan FM standard to Euro FM I was wondered that they used a lower heterodyne (-10.7Mhz) in the 76-90Mhz band .When I switched standard to 87.5-108Mhz the processor logic changed. Now here with the Euro standard a higher heterodyne is used ( +10.7Mhz to carrier freq). What you need to do now - is to check and measure your current oscillator frequency under these 23 volts on varicaps (I hope it is still alive) and retune it to new frequency band. Force it to oscillate 87.5+10.7=98.2Mhz with 7.5V and 108+10.7=118.7Mhz with 21V as shown on the schematic diagramm of Pioneer F-701. Disconnect the tuner unit from control voltage source and take variable voltage from your bench laboratory power supply or an external battery with a potentiometer (or use voltage of inner power unit). Changing the control voltage you watch the frequency on your measuring tool. I do not use the direct method with an oscilloscope for a frequency couting . The best and cheap tool is TinySa portable spectrum analyzer. You do not have to connect this device to a tuner directly. Just place its antenna( or any short piece of wire) near by an oscillator. It is very good tool to tune hi frequency circuits you will have to retune in your radio.
Synteza słuzy tylko i aż do trzymania częstotliwości "za mordę" natomiast obwody wejściowe jak i sam oscylator jest przestrajany poprzez warikapy właśnie napięciem zwanym warikapowym. To tuner tak naprawdę analogowy...
Daj se z tym spokój. Kup se coś prostego i taniego. Ja mogę ci pomóc w ten sposób, że znajdę obok gdzie mieszkasz wysypisko i załatwię tego tam przyjęcie. Może to zutylizują, a może nie. W każdym bądź razie pozbędziesz się dziadostwa.
![Naprawa Radmora - Odc.23 [Reduktor Szumu]](http://i.ytimg.com/vi/j6G7T-V6plk/mqdefault.jpg)
Hi! Mr.Cacek ! Now after you switched your processor to our Euro FM band setting 87,5 Mhz , it ordered cx7925A to be waiting for 87.5+10.7=98.2 Mhz from the tuner oscillator. Then your CX7925 with the pump+filter circuit produces a voltage for the oscillator varicaps and the oscillator should make 98.2 Mhz and give that freq back to CX7925b. But this doesn't happen because the oscillator is still limited by Japanese band. I guess it makes very low frequency ( possibly 90-10.7=79.3 Mhz ) . The CX7925b receives wrong ( and low) frequency and following its own logic to increase voltage for varicaps it waits for right higher frequecy in return. In this stupid situation what it can do - is to send more higher and higher voltage untill it reachs a limit of 23Volts , still having no desirable frequency from the oscillator.
Can you measure somehow your current oscillator frequency ? I remember -
when I re-tuned my Technics st-g90 from Japan FM standard to Euro FM I was wondered that they used a lower heterodyne (-10.7Mhz) in the 76-90Mhz band .When I switched standard to 87.5-108Mhz the processor logic changed. Now here with the Euro standard a higher heterodyne is used ( +10.7Mhz to carrier freq). What you need to do now - is to check and measure your current oscillator frequency under these 23 volts on varicaps (I hope it is still alive) and retune it to new frequency band. Force it to oscillate 87.5+10.7=98.2Mhz with 7.5V and 108+10.7=118.7Mhz with 21V as shown on the schematic diagramm of Pioneer F-701. Disconnect the tuner unit from control voltage source and take variable voltage from your bench laboratory power supply or an external battery with a potentiometer (or use voltage of inner power unit). Changing the control voltage you watch the frequency on your measuring tool.
I do not use the direct method with an oscilloscope for a frequency couting . The best and cheap tool is TinySa portable spectrum analyzer. You do not have to connect this device to a tuner directly. Just place its antenna( or any short piece of wire) near by an oscillator. It is very good tool to tune hi frequency circuits you will have to retune in your radio.
Dokładnie to tak wygląda jak by oscylator pomimo wysokiego napięcia Vt nie wchodził na tak wysokie pasmo.
Tam nie ma napięcia warikapowego. Jest syntezer częstotliwości, przestrajany pętlą fazową PLL.
Synteza słuzy tylko i aż do trzymania częstotliwości "za mordę" natomiast obwody wejściowe jak i sam oscylator jest przestrajany poprzez warikapy właśnie napięciem zwanym warikapowym. To tuner tak naprawdę analogowy...
Na stronie hifi engine jest serwisówka do F-701
Przydałaby się do modelu F-777 a tej brak
Witam. Ale pytanie, czy warikap zmieniał napiecię się przed zmiana zakresu?
Wspominam o tym, na zakresie japońskim działa wszystko poprawnie
Ladny kawalek sprzetu ale kto slucha radia FM :/
Tacy starzy ludzie jak ja... 😜
@@zbyszek1871 tam bredza tylko nie lepiej cd i bez reklam
Też słucham FM
@@jasnyjasny27 nie ma w polsce DAB ? to jeszcze bym jakos pogodzil ale w kuchni do gotowania.
@@adredyjak już to dab+
Daj se z tym spokój. Kup se coś prostego i taniego. Ja mogę ci pomóc w ten sposób, że znajdę obok gdzie mieszkasz wysypisko i załatwię tego tam przyjęcie. Może to zutylizują, a może nie. W każdym bądź razie pozbędziesz się dziadostwa.