| Author |
Message |
    
Red_devil
Junior Member
Username: Red_devil
Post Number: 21
Registered: 10-2004
| | Posted on Monday, January 17, 2005 - 4:52 pm: | 
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CEFers,
Any opinions on the best modification. Option “B” seems to be the simplest one to do. However, I want to make sure that the results are reliable. Any input is appreciated.
Option “A”
CB Tricks Method #1
First, remove power to the radio. Remove the bottom chassis cover of the radio.
Remove R113 and D68 as shown above.
Connect a jumper wire between +8V and J9 pin F1.
Option “B”
CB Tricks Method #2
First, remove power to the radio. Remove the bottom chassis cover of the radio.
Remove JP195 and JP196.
Connect a jumper wire between +8V and J9 pin F1.
Option “C”
Copper’s Mod
Unlock the Fine Tune Control!
#1 ~ Remove R-113
#2 ~ Remove D68
#3 ~ Remove D-38
#4 ~ Place wire across D-38 mounting holes.
#5 ~ Place wire from J-14 pin +8V to J-9 pin F1
CEF - 447
Red Devil - 392
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Sonoma
Intermediate Member
Username: Sonoma
Post Number: 150
Registered: 11-2001
| | Posted on Monday, January 17, 2005 - 10:20 pm: |
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I did option B on my radio and it worked fine |
Red_devil
Junior Member
Username: Red_devil
Post Number: 22
Registered: 10-2004
| | Posted on Tuesday, January 18, 2005 - 9:24 am: |
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Sonoma,
Did you just cut the jumpers or totally remove them?
CEF - 447
Red Devil - 392
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Sonoma
Intermediate Member
Username: Sonoma
Post Number: 152
Registered: 11-2001
| | Posted on Tuesday, January 18, 2005 - 11:41 am: |
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I just clipped them and pulled them apart so they would not touch.
sonoma |
Red_devil
Junior Member
Username: Red_devil
Post Number: 23
Registered: 10-2004
| | Posted on Tuesday, January 18, 2005 - 2:30 pm: |
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Sonoma,
Thanx! I figured that is how I would do it if I went with Option B. Quick and easy! Thank you for your input.
Others,
If you know of any advantages or disadvantages to the other options, Please share.
CEF - 447
Red Devil - 392 |
Chad
Intermediate Member
Username: Chad
Post Number: 104
Registered: 11-2004
| | Posted on Monday, January 24, 2005 - 9:15 am: |
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Red Devil, Did you have to re-tune it?
Chad |
Red_devil
Junior Member
Username: Red_devil
Post Number: 26
Registered: 10-2004
| | Posted on Monday, January 24, 2005 - 2:11 pm: |
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Chad,
I did adjust VERY slightly L20, L21, and L22 just to double check that the center of the clarifier was dead center of the freq. I did use The CB Tricks Method 2 (Option B above). It was the easiest one for my limited skill level.
I had this posting and another up for a while and the only positive feedback I received was from Sonoma (above). Thanx Sonoma!
The results... I talked to 447 (unknown if he is a CEF member) in New Jersey earlier today. I guess it is working well. I have had no complaints since the mod.
I have however, noticed some frequency drift (both before and after the mod) when the radio is cold. Once the heat sinks into the radio it performs nicely.
I did find it a bit challenging to work in the close quarters since the jumpers and L20/21/22 are under the overhang of the faceplate circuit boards. You need to be careful removing the knobs first and moving the faceplate area out of the way. Put some type of insulating material between the faceplate cards and the main circuit board while clipping and adjusting. I was VERY careful. No smoke on the bench… Only on the air :-).
I know you did not ask for all of this information but, it may help another reader.
73
CEF 447
Red Devil – 392 |
Chad
Intermediate Member
Username: Chad
Post Number: 106
Registered: 11-2004
| | Posted on Tuesday, January 25, 2005 - 9:01 am: |
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Reddevil
I keep my 2547 on in the winter (well this is the first winter in the new home). My shack is in the rear of my garage and is heated but can easily get down to the mid 40's when it's approaching 0 outside. I then bump it up to the 60's when I'm out there. I just leave the radio on and it seems OK especially Sat night for Sunday NET I REALLY want to do this clarifier mod but have been aprehensive due to the fact that I do not have a benchtop freq counter that will go high enough to do the PLL adjustment at this time. I may give it a shot in the most reversible way now that you said that it's not that bad. I was just invisoning it jumping alot with the mod and I would not be able to even get it close without the proper test equipment.
ALL of your information was appreciated, thank you!
Chad |
Red_devil
Junior Member
Username: Red_devil
Post Number: 29
Registered: 10-2004
| | Posted on Tuesday, January 25, 2005 - 1:54 pm: |
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Chad,
Live dangerously! If your radio is similar to mine, even an idiot like me can do it. If it does not work well, bend the jumpers back over, slap on a dab of solder and remove the extra power lead. You'll be back where you started. I only used the on board freq. counter for my adjustment and I have heard no complaints. Maybe I just got lucky. I don't know.
Happy Tweaking :-)
CEF 447
Red Devil – 392 |
Chad
Intermediate Member
Username: Chad
Post Number: 107
Registered: 11-2004
| | Posted on Wednesday, January 26, 2005 - 9:01 am: |
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Red devil
Did it last night went fast and works great. I went by thge front panel counter but then drove out and borrowed a real freq counter. It was within factory spec! Thanks for your time!
Chad |
Red_devil
Junior Member
Username: Red_devil
Post Number: 30
Registered: 10-2004
| | Posted on Wednesday, January 26, 2005 - 2:19 pm: |
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Chad,
No problem. Glad to share. I usually find myself getting assistance from others. It is nice to help someone else for a change.
Hope to hear you one of these Sundays. I'll listen for CEF 433 from the Land of Lincoln :-).
I try to hit the 13LSB as much as I can.
CEF 447
Red Devil – 392 |
