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Message |
    
1861
Intermediate Member
Username: 1861
Post Number: 285
Registered: 2-2004
| | Posted on Wednesday, August 03, 2005 - 8:50 pm: | 
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I THOUGHT THE RX WAS OUT ON MY 2000GTL , IT RECEIVES FINE UP TO ABOUT 3/4 MILE THEN STARTS FADING TO NOTHING AFTER ABOIT 1 MILE . I WAS NOTICING TODAY , WHEN IT WAS QUIET , IT IS INFACT RECEIVING AT DISTANCES , BUT SO QUIET YOU CAN HARDLY TELL . IT ISN,T THE SPEAKER , TRIED SEVERAL . ANY IDEAS APPRECIATED . JUST GOT IT BACK FROM A GUY WHO CLAINED TO BE A TECH , HE FINALLY GAVE UP AND SAID HE COULDN,T FIGURE IT OUT . FOUND OUT HE WASN,T A TECH , AND HAD NO TEST EQUIPMENT . |
Hollowpoint445
Advanced Member
Username: Hollowpoint445
Post Number: 610
Registered: 6-2004
| | Posted on Wednesday, August 03, 2005 - 9:46 pm: |
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Don't feel bad 1861 - in my experience 99.9% of CB techs aren't electronics technicians. They've got screwdrivers to open the case, a book to tell them what to clip, and finger nail clippers to clip the limiter.
It sounds like the receiver is out of alignment because it's working a little but not as well as it should. Since it's already screwed up there's no harm in trying to peak it up yourself. Tune into a weak station and turn inductors L6, L5, and L4 with a non-inductive tuning tool. Try to get the maximum signal and don't be afraid to go back and forth between the inductors to get the best signal.
If that doesn't solve the problem then you'll need to find a tech with signal generators to do a more indepth receiver alignment. |
Kid_vicious
Intermediate Member
Username: Kid_vicious
Post Number: 453
Registered: 9-2004
| | Posted on Wednesday, August 03, 2005 - 9:47 pm: |
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1861, start replacing the electrolytic caps in the radio. its old and they are probably drying out. this will affect your modulation, receive, power supply, etc.
get a parts list and order new caps. its much cheaper then sending teh radio to a tech.
i bet doing this and doing a tune up on the receive will cure your problem. if not, you hve made the radio better anyway.
for more receive gain, replace TR14 with a 2sc2999 transistor.
increase the value of C18 to 330mfd.
increase the value of the big cap next to VR10 to 2200mfd.
increase the value of the cap for the power supply, (bottom side of radio) to 5,000mfd or 6800mfd.
also replace all caps rated at 10 volts with 16volt caps.
hope this helps. |
1861
Intermediate Member
Username: 1861
Post Number: 287
Registered: 2-2004
| | Posted on Wednesday, August 03, 2005 - 10:03 pm: |
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ONE MORE THING , THE RF GAIN KNOB HAS NO EFFECT WHATSOEVER , LIKE IT ISN,T HOOKED UP OR SOMETHING . SQUELCH KNOB DOES WORK |
Hollowpoint445
Advanced Member
Username: Hollowpoint445
Post Number: 612
Registered: 6-2004
| | Posted on Thursday, August 04, 2005 - 6:18 am: |
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If the RF gain knob has no effect it sounds like the AGC circuit has been altered for some reason. Did you always own this radio? Has it worked well before? Was it working before your tech looked at it? What did your "tech" do to it? |
1861
Intermediate Member
Username: 1861
Post Number: 288
Registered: 2-2004
| | Posted on Thursday, August 04, 2005 - 8:39 am: |
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No , I aquired the the radio as it is . It has had extra channels added , so maybe that is what the problem stems from , don,t know . |
Hollowpoint445
Advanced Member
Username: Hollowpoint445
Post Number: 613
Registered: 6-2004
| | Posted on Thursday, August 04, 2005 - 11:31 am: |
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It full alignment sounds like a good place to start, and see how it works after that.
Before you try anything though - play with L6, L5, and L4 to see if it helps. It could just be that someone was tweaking the wrong pot and got things out of alignment with those three inductors. You can't really hurt it at this point, and you might get it working again.
Maybe someone was trying to enhance the already excellent receiver and got things out of whack.
Extra frequencies shouldn't cause this kind of problem unless someone aligned the radio for a specific frequency far from the normal CB channels and that caused the lack of sensitivity. |
1861
Intermediate Member
Username: 1861
Post Number: 290
Registered: 2-2004
| | Posted on Thursday, August 04, 2005 - 8:44 pm: |
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NO CHANGE PLAYING WITH L 6 L5 & L4 |
1861
Intermediate Member
Username: 1861
Post Number: 306
Registered: 2-2004
| | Posted on Monday, August 22, 2005 - 9:14 am: |
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OKAY , I FOUND WHERE MY PROBLEM IS , BUT BEFORE I MESS ANYTHING UP , MAYBE SOMEONE CAN GIVE ME SOME GUIDANCE ? I TOOK BOTTOM COVER OF AND LIGHTLY TOUCHED AROUND ON BOARD WITH MY FINGER TIP . AT ONE SOLDER POINT , JUST TOUCHING , NOT PUSHING , THE RECEIVE COMES ALIVE , REMOVE FINGER AND IT,S GONE AGAIN . AS LONG AS I,M TOUCHING THAT SOLDER , IT WORKS FINE . I CAN TOUCH IT WITH PLASTIC SCREWDRIVER AND IT DON,T HELP . SEEMS LIKE MY FINGER TIP PROVIDES A NEEDED GROUND . ANY SUGGESTIONS APPRECIATED . |
Sg569
Intermediate Member
Username: Sg569
Post Number: 222
Registered: 12-2004
| | Posted on Wednesday, August 24, 2005 - 10:32 am: |
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that does sound like a ground prob. Can you follow the trace from that solder point?
Have you put a meter on that point and a good ground?
USE the correct tools!!! I have blown traces by not using the proper tools.
Just had to ask the dumb ??? to get them out of the way, ya know.
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