I need some advice of any of you.
Cobra - 148GTL - Malaysia - PCB EPT014811Z
You can get its schematics here: http://www.cbtricks.com/radios/rci/tr_2 ... sm_sch.pdf.
I got a 148GTL, dead on arrival, with the following characteristics:
- PLL MB8719
- Crystal X3 is 11.1125MHz (Someone may have changed it to achieve channel -79)
- CB/PA key is unconnected. Radio is hardwired to CB (This key must have been used to extra channels)
- HI/LOW key is unconnected. Radio is hardwired to HI (This key must have been used to extra channels)
- Almost everithing else is unchanged.
- I have the trippler circuit working (after replace TR20) and I can read 33.3375Mhz at the TR20 emitter.
- I have VCO Unit (UHIC070) working and I can set valid frequencies (34765Mhz to 35205Mhz) variating voltage on its pin #5.
- I have plenty of sure PLL is working good, since I tested it on another radio and it works as expected.
- Frequencies at the FI (PLL Pin #17) are difference between the frequencies present in TR20 emmiter and base, as expected, and are about 1.5Mhz (if my memory serves me well at this time).
Since I was away from analogic electronics for about 20 years, this error is beating the hell out of me.
So, I ask you for guidance. I can perform any tests you like, if requested. But since I'm doing it in my spare time, it can take a day or two for the results.
Thanks in avance.