The Defpom Forum, for RadioMods, S&M Software and Music by The Defpom

Guys

A friend of mine has a Revision 2 Cobra 200 GTL DX (PCB# PFM-0090A-BE)

It's well documented that the coarse clarifier shift isn't sufficient on the Rev 2 to reach the zero's (obviously it needs 5Khz at the very least but only manages approx 3Khz)

I'm led to believe there are a number of ways to increase the frequency shift of the clarifier.

Does anyone know the easiest way to correct this problem on the Cobra 200???

Many thanks

Change crystal X2.
Common fault.

Thank you Rick - excuse my ignorance, I take it X2 is 10.240Mhz reference?

X2 is the PLL loop Osc.
X2 is a special crystal and not just any old 10.2400 MHz will do.
You will need to realign the PLL loop Osc when you replace the crystal.
Have a word with Richard at Truck King he may still have some, you can tell him that Rick from Euro Radio Co put you in touch.

Cheers Rick, I've done just that - Richard said 'Rick who?'

Hope you can give me some guidance when I come to re-align the PLL loop osc

Thanks again, much obliged.

It would be best to do a full realignment job.
You will need a good frequency counter at least 6 digit with a 10:1 probe.
The info can be found on CBTricks.
http://www.cbtricks.com/radios/cobra/20 ... e_info.pdf

If you are stuck with it, I can do it for you but it is not free.

Would it be cheaper than buying an Anritsu or Marconi test set???

Can you send me a PM with your 'phone number please Rick?

Many thanks.