chinese YWR-33 receiver schematic needed

[Eugen_E]

I have a small chinese radio, the YOKO World Band Receiver YWR-33 that covers almost all the broadcast bands: LW, MW, SW 5.9-15.8MHz, FM (it has a PLL synthesis with LCD display).

I have a problem with my YWR-33: I think the synthesis doesn't lock on the upper half of all the bands. For example the receiver tunes corectly in the interval 88-98MHz, but at higher frequencyes I hear a strange rumble and a station that is on 98.3. If I go to higher frequencyes the display shows the increasing frequency, but all I hear are rumble and the 98.3 station.
If the receiver is not powered for a long time - a week - when I turn it on it works for about 5 minutes corectly and after that the malfunction reapears. I suspected some capacitors because of the frequent malfunction, but I can't be sure.
Not having the schematic I started with checking the VCO control voltages, but as the YWR-33 is quite "crowded" I finally cut a wire that powers the LCD board and now the frequency is not displayed.
I know a chinese receiver schematic is hard to get, but I hope I will repair my YWR-33.
So, I want to ask you if you have an YWR-33 schematic, or some ideas about how it can be solved to post them. Thanks in advance.

 

[honggun]

I think the YOKO World Band Receiver YWR-33 is not made in china.

 

[Eugen_E]

On the receiver box is written "4 band PLL receiver", "Made in CHINA".
So the YOKO YWR-33 is made in China.
I was unable to find any information on YOKO and their receivers on the net. Only some sale information on EBAY regarding some YOKO receivers and mp3 players.

 

[Eugen_E]

Hi
I want to ask you again about the YWR-33 schematic.
If you have the schematic of this receiver or you seen it or used it I am interested in asking some questions. It seems I'm the only one who has this receiver :?: .

If you have the schematic please post it.


Thank you