Cobra 2000 GTL Alignment?

[Eastside]

I need the alignment procedure for the Cobra 2000 gtl with PC-497 AB board.

 

[GnG8d]

CB Tricks doesn't have it?

 

[Eastside]

CB Tricks doesn't have it?

Not that I could find?

 

[Robb]

Cobra 2000GTL

http://www.cbtricks.com/radios/cobra/2000gtl/graphics/cobra_2000gtl_sm.pdf

 

[Eastside]

Thanks Robb.

 

[Eastside]

When setting the driver bias and the final bias..you set your dmm on mV right?

I got a new dmm...never had one with mV and mA setting.

 

[sonoma]

you put it on MA as the specs calls for.

 

[Eastside]

you put it on MA as the specs calls for.

Thanks.....prolly should have looked before asking.

 

[Eastside]

I am at the stage of checking the driver bias and the manual says to check at tp3.....it looks like on this radio that there is no tp3...it sez tps on the board and just 2 empty pin holes?

 

[Robb]

TP8 is the driver bias point, and TP7 is the final bias point. It is all in the manual link I posted yesterday.

You will find two wires (TP7 & 8), usually purple and green that have push-on connectors at the +8v junction on the board, found here in this picture:

 

[Eastside]

TP9 is the driver bias point, and TP8 is the final bias point. It is all in the manual link I posted yesterday.

You will find two wires (TP8 & 9), usually purple and green that have push-on connectors at the +8v junction on the board, found here in this picture:

I wish that pic was better quality so I could see how he had his dmm set.

Yeah...I have set the bias on my uniden washington and it is the same.....but the 2k service manual says tp3....so I said that must be a typo and tried tp7 and tp 8 to check the final bias n the driver bias.....but I must have this new meter set wrong because I am not getting a reading......my new meter is a Fluke 179.....I set it on mA Hz and the leads are plugged into the com n V....

 

[Robb]

I just reviewed the SM for this radio, and it explicitly says TP7 & 8. Not to mention, I have done this about a bazillion times. Don't know what you are reading, but you should re-read it before you bust a move.

The DMM setting should be on 'mA' . . .

 

[Eastside]

I just reviewed the SM for this radio, and it explicitly says TP8 & 9. Not to mention, I have done this about a bazillion times. Don't know what you are reading, but you should re-read it before you bust a move.

The DMM setting should be on 'mA' . . .

If set on mA how do you plug in yer probes?

 

[Robb]

If set on m how do you plug in yer probes?

Either the purple or green wire is closer to the driver or the final; they have been different colors in some radios. The wire closest to the final will be the final bias wire; the other will be the driver bias wire. They both share +8v posts sticking up off of the board, near the modulation VR pot. Connect the '+' probe to the post and insert the '-' probe lead inside the connector; then adjust the driver bias first using the appropriate wire.

On the Fluke, the COM will be the '-' test lead, and the '+' test lead should go to the 400mA.

Set the radio in either LSB or USB, turn the Mic Gain control all the way down, key the mic, and then read the meter. Adjust the bias pots according to specs. Easy peazy.

 

[GnG8d]

I'm afraid this isn't going to end well