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shadow
| | Posted on Tuesday, April 22, 2003 - 1:37 pm: | 
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Recently I purchased a used connex 4800 dxl and upon further inspection, I noticed that there was an aftermarket switch in the rear of the unit. This switch goes to circuit #c-180 near a transformer(?) at the rear of the radio, near the power plug. I have switched it on/off and have noticed that there are no visible changes.
Sencondly whoever set this radio up installed a ranger echo board in it and seems to operate with no problems, the swr switch was removed to accomodate the installation of the switch for the echo/reverb board.
This radio will squeal when the mike gain is moved above 12:00 position, indicating to me that it is not tuned properly or possibly the the talk back circuit is interferring with the modulation.
This radio is set up w/ a wilson 5000 tuned to 1:1 on ch20 on the 11 meter band. A 600 palomar elite is also set up in line but not used until this problem is resolved.
(1) what is c-180? I can't seem to locate a schmatic for it and would like to know what the theory behind this mod was. Is it possibly a talk back circuit, if so they doo-dooed up because it works on both positions.
(2) what belongs in the c-180 slot looks like possible a diode.
(3) What are the long term effects of these mods if any?
(4) Does this radio come with a built in talk back from the factory and if the above is indeed a talkback circuit do I need to put a varible switch to adjust it down to a point that it won't feed back?
I have taken this radio to several shops but no one seems to know beans (nice way to put it) about this unit and none have schmatics for it, and I refuse to let them tinker w/ especially when they have shown they don't know anything about it.
Any help would be greatly appreciated. |
shadow
| | Posted on Tuesday, April 22, 2003 - 4:40 pm: |
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My apologies Cicuit c-180 as mentioned above is NOT The one upon close inspection it is circuit #D-75 which would be a diode...
Sorry about that
s |
Viking
| | Posted on Tuesday, April 22, 2003 - 6:46 pm: |
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The Galaxy DX2517. Like the Connex, it also has the EPT6900-10Z board. There they have the parts layout and a schematic (and other info for it).
1) I don't see C-180 on the parts layout, schematic nor parts list.
2) C-180 would/should be a capacitor.
3) Don't know on this one.
4) Talkback is not a stock item for the 4800DXL (at least the older ones without the echo board). But it's easily attainable by going through J7, an unused 6-pin jumper 'below' the transformer.
Hope that helps. |
shadow
| | Posted on Tuesday, April 22, 2003 - 8:53 pm: |
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Thanks for the reply viking, I boo-booed on the circuit I reposted and corrected the proper circuit is D-75 Sorry for the mistkae... |
Viking
| | Posted on Wednesday, April 23, 2003 - 10:47 am: |
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Well heck, now that I find D75, I see C180. Hmmm. At least on the parts layout view.
D75 goes to the audio amp. See what your modulation does with the switch up and down.
Just a thought. |
shadow
| | Posted on Thursday, April 24, 2003 - 7:22 pm: |
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ok d-75 was removed from someone to give the radio talkback. After replacing the diode all is well as far as the squel and hum.
Next, to properly install a variable talkback what would the proper proceedure be.
TThanks to Viking for all his help. Maybe one day I can find someone to do this for me that I can trust. Myself included. |
Viking
| | Posted on Friday, April 25, 2003 - 4:24 pm: |
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Variable talkback?
Radio with component side up, front towards you:
- Find J7, the 6-pin jumper 'below' the transformer (right hand side).
- The right 2 pins should be labled "TX" and "GN". Install a SPST switch (toggle, rocker...) between these.
- The 2 left pins should be labled "WT" and "W+". Install your variable dial between these 2. I don't know what value to use so you'll need to experiment. Or maybe someone can chime in here.
- leave the middle 2 alone.
The switch turns it on and off and the variable, well, makes it variable.
I did the switch on mine but haven't tried the variable. |
Shadow
| | Posted on Friday, April 25, 2003 - 7:15 pm: |
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Thanks once again Viking, That did the trick. as far aas the variable part that is not that important me me , all I want to do is set the radio in vehicle and shut it off again. I really don't care to hear me talk on a radio, just want to be able to set it and go.
The J-7 circuit on this one is labeled tb instead of tx, maybe just an older/newer version of the board, no big deal I figured it out with your help.
I bought this radio because for some wierd reason I figured it had potential and due to the fact I already have a 4400hp and love it. This one seems to perform almost (Strees almost) as good as the 4400 and with a little tinkering with the info you have given me Maybe this can be accomplished
now that we have a schmatic. Now that I am armed with that I can REALLY be dangerous....
Thank you again for you help and knowledge....
S |
Viking
| | Posted on Monday, April 28, 2003 - 4:05 pm: |
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Glad it worked. |
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