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Cobra 2000 GTL DeBunking

88_bandit

Active Member
Dec 13, 2009
10
0
31
Okay I recently purchased a used 2000 and upon receiving i noticed a weird modificaton. It is using the CB/PA switch and is hooked up to the PLL area and consists of:
1 - c945 transistor
2 - 4148 diodes
1 - 10k Ohm resistor

Also there is a 4148 diode on the bottem side of the power supply board with a cut trace???
Any help would be much appreciated.

73's20220920184817.jpg
 

Recon

NY 881
Jul 28, 2019
789
999
103
Up-State NY
Okay I recently purchased a used 2000 and upon receiving i noticed a weird modificaton. It is using the CB/PA switch and is hooked up to the PLL area and consists of:
1 - c945 transistor
2 - 4148 diodes
1 - 10k Ohm resistor

Also there is a 4148 diode on the bottem side of the power supply board with a cut trace???
Any help would be much appreciated.

73'sView attachment 60666
Does it transmit and receive?
 

nomadradio

Analog Retentive
Apr 3, 2005
5,557
8,175
573
Louisville, KY
www.nomadradio.com
If you know what frequency each of the legal 40 channels should show, you can see what frequencies above 40 or below channel 1 you'll get by flipping the PA and ANL (maybe?) switches. They will change the counter reading on some of the 40 channels, but not all.

That radio has more secret sauce in it than a Kansas City barbecue joint.

73
 
Last edited:

Rwb

tell the devil im gettin there as fast as i can,r
Jun 30, 2018
3,327
4,183
273
67
If you know what frequency each of the legal 40 channels should show, you can see what frequencies above 40 or below channel 1 you'll get by flipping the PA and ANL (maybe?) switches. They will change the counter reading on some of the 40 channels, but not all.

That radio has more secret sauce in it than a Kansas City barbecue joint.

73
old sears roadtalker i got has 5 extra bands.every band has about 15 diffrent frequincys from standard 40. and not in sequnch either
 

NZ8N

Sr. Member
Dec 25, 2017
445
710
103
58
88 Bandit's C2000 PLL mods.jpg

Pin 11 - Grounding this drops you 320kc (or 32 channels from whatever Pin 10 is set to.
If Pin 10 is high (normally open or floating) then Ch 15 becomes 26.815 MHz, or
If Pin 10 is low (grounded) then Ch 15 becomes 27.455 MHz

Pin 10 - Normally open or floating (pulled high with internal resistor), grounding this pin "bumps" you up by 640kc, or the equivalent to 64 channels, which puts Ch 1 to 27.605 MHz.

Pin 9 - +8v VCC PLL chip supply pin.

Page 3 (of 4) gives you the frequency chart.

They did not implement Pin 12 or Pin 13 to backfill frequencies missed by the above mod (27.425 for instance).
 

ShakyMcQuiver

Member
Apr 11, 2018
40
26
18
Search the net for 'Digimax Lite'. These are a microprocessor type of mod that gives you all the channels, even the A's and displays it correctly on your counter.

When I bought my Cobra 2000 it had the extra crystals wired up to one of the radio's switches too. Very poorly done BTW.

Before Arduinos and other microcontroller type of kits, I made my own crystal board using relays. It's much more stable, but by no means perfect. Basically it's like the old Expo kits but without the rotary switch (that stick or fail).

I want to eventually upgrade to the Digimax system, (the word 'eventually' in this case means... when the WIFE says I can) LOL!

I wish I still had my old college stuff. I've done some microcontroller work. Loads of fun!
 
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Woody-202

Sr. Member
Sep 5, 2018
567
901
103
66
Search the net for 'Digimax Lite'. These are a microprocessor type of mod that gives you all the channels, even the A's and displays it correctly on your counter.

When I bought my Cobra 2000 it had the extra crystals wired up to one of the radio's switches too. Very poorly done BTW.

Before Arduinos and other microcontroller type of kits, I made my own crystal board using relays. It's much more stable, but by no means perfect. Basically it's like the old Expo kits but without the rotary switch (that stick or fail).

I want to eventually upgrade to the Digimax system, (the word 'eventually' in this case means... when the WIFE says I can) LOL!

I wish I still had my old college stuff. I've done some microcontroller work. Loads of fun!


Yep, I like my DigiMax. Have one in a 29xlr and another in a 148gtl

8_1000_466-tiny.jpg
 

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