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Message |
    
Olerowdy1
New member
Username: Olerowdy1
Post Number: 2
Registered: 7-2007
| | Posted on Wednesday, August 20, 2008 - 2:25 am: | 
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I recently purchased a 140gtl and have started the process of fine tuning it to my liking , amazingly I found one that had not been touched internally .I want to modify the clarifier & The problem I am having is locating r187 , d35 & d36 . My eyesight is not what it used to be and this circuit is so much more densely populated in comparison with the 148GTLs that I have recently done . I have done google searches to find any images of the circuit board that may clue me in as to the location of these components . I also searched for images of the 142GTL circuit board , But had no luck there either . any help would be greatly appreciated . |
Olerowdy1
New member
Username: Olerowdy1
Post Number: 3
Registered: 7-2007
| | Posted on Tuesday, August 26, 2008 - 6:31 pm: |
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Would it help if I mention its the same radio as the 142gtl ? Just in a mobile case . I know somebody still has one of the 142s that has the clarifier mod done on it . The closest thing that I found on the r187 search was r178 . Is it possible that they mis-labeled some radios in the printing of the boards ? |
Hotwire
Senior Member
Username: Hotwire
Post Number: 2590
Registered: 1-2005
| | Posted on Tuesday, August 26, 2008 - 10:47 pm: |
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I'm not real sure but I'll try to help.
I think r187 is in the area right behind the voicelock control probably well hidden, it should be a 22k resistor.
Diodes d35 and d36 should be right next to each other back towards the center but along the left side of the radio. Componets r145, r144, r143,L24 and vr3 are pretty much surrounding d35 and d36, so if you can find some of those it might help. The 140gtl schematic I studied was not the clearest and my eyes are not the greatest either but this is the best I can do for you. Hope this helps, good luck and welcome to the Copper Forum! 73
Kenny
CEF491
Mudduck County
Indiana
The Hotwire Mobile coming soon to a radio near you!
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Olerowdy1
New member
Username: Olerowdy1
Post Number: 4
Registered: 7-2007
| | Posted on Wednesday, September 03, 2008 - 7:14 am: |
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Thanks for your reply Hotwire , I had looked at schematics & block diagrams myself & it really help me as much as I had hoped it would . I will dig back into it soon and take note as to the suggestions you have listed |
Press_man
New member
Username: Press_man
Post Number: 8
Registered: 5-2008
| | Posted on Tuesday, October 21, 2008 - 3:21 pm: |
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Hi guys I hope you've already worked out the locations for your 140. Yes the 142 is the same as is the Ward 719. On the componant side of the radio I traced the wires on the clarifier. Center goes to diodes. cut and jump D-35, cut D-36, cut R-187 this goes to ground. Move right clarifier wire from left of R-187 to ground on right side of resistor. Move center wire from D-35 location to a choke you'll add to the varactor(add 2uh choke at varactor). Move left(orange) wire to + of C-66. I got a smooth 1.5 kc slide. for more range try a 5.6uf choke.(quick and uneven). In short trace the clarifier wires. |
Press_man
New member
Username: Press_man
Post Number: 9
Registered: 5-2008
| | Posted on Tuesday, October 21, 2008 - 3:44 pm: |
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Forgot to add tune instructions for Cobra 140. Adjust L26,L27,L28,L29,L36 for max on USB ch19. VR6 am power. VR10 power meter. VR7 SSB ALC. VR8 driver bias. VR9 final bias. L39 tvi trap, adjust for least signal on TV ch5. Remove TR33 am AMC (about 1/2 way between audio transformer and mike jack). VR1 S-meter. Adjust CT3 to center clarifier. If you need AM power mod for VR6 let me know. Be sure to use NON metalic tune tools. |
Johhn
Intermediate Member
Username: Johhn
Post Number: 150
Registered: 8-2007
| | Posted on Saturday, November 08, 2008 - 5:06 pm: |
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Cobra 140, D-36 is just in front of the
PLL-chip, Step #3,Expo 100 expander'B' kit on
someone elses site.Do a google it's there.
johhn 361 |
