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Icom IC 718 schematic FOUND!




 
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Author Topic: Icom IC 718 schematic FOUND!  (Read 17370 times)
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WD8BIL
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« on: December 10, 2007, 01:15:49 PM »

OK Guyz,

I have the pdf of the 718 schematic. It is a 2 meg file. Unfortuantly attachments here cannot exceed 1meg.

SO.... ifn ya send me an email or PM with ur email address I will send it to you.

bud@wd8bil.com

It appears (on page 14) that there are ALC adjustments that can be made. IC 1701 appears to be the place to start.

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ka2zni
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« Reply #1 on: December 22, 2007, 12:21:39 AM »

welcome to the world of hollow-state---- Hello Bud, havn't talked to you in a while! Merry Christmas!

Anyway, does the IC need to be removed or jumped around? I don't have enough knowledge to go sticking my potato skinners in there just because...

Anyone found the secret yet?
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KF1Z
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Are FETs supposed to glow like that?


« Reply #2 on: December 22, 2007, 08:56:54 AM »

Most Icoms have an on-board ALC adjustment....

You have to decide whether you are EVER going to use it on sideband or CW again before you do much...

If not, then you can usually adjust the ALC so it doesn't act on your audio at all...
(no alc) if you do this though, in SSB and CW, the rigg will try to put out as much power as it can (probably around 175 watts) and cause damage..
But will work FB in AM.

If you want to keep all modes available, just reduce the ALC a little bit.....


There should be also an AM level pot on the board, use that to adjust the carrier level, with the front panel "power" pot fully clockwise...

good place to be is about 15 watts maybe 20 max.




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Pete, WA2CWA
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« Reply #3 on: December 22, 2007, 01:25:55 PM »

If you want to diddle with the ALC, why not just float a variable 0 to -10 volt supply connected to the ALC pin and ground in the Accessory jack. You can adjust it for whatever you want depending on mode. If you screw with the internal ALC adjustments, you might just want to kiss your finals one last time before you send them to their after-life.
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Pete, WA2CWA - "A Cluttered Desk is a Sign of Genius"
WD8BIL
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« Reply #4 on: February 08, 2008, 08:57:51 AM »

Because, Pete, the larger of the 2 voltages will dominate. When the internal ALC goes higher than the outboard it will still shut the rig down. And with the over-active ALC, at least in my rig, it happens far to much.

I figure, if I set the internal ALC to shut down the "dangerous" peaks I'll have plenty of headroom at a 20 watt carrier to drive an amp and have respectable strap.


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W5EFR
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« Reply #5 on: July 22, 2008, 11:43:14 AM »

I know this is an old thread...


But if anyone is interested, I have the IC-718 Service Manual, in PDF file... 8Mb
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W2WAS
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« Reply #6 on: July 22, 2008, 08:34:12 PM »

Scott,

I would appreciate a copy of the service manual.  My email address is good on QRZ.com.

73, Tony W2WAS
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73, Tony W2WAS
W5EFR
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« Reply #7 on: July 30, 2008, 09:40:55 PM »

Heading your way....
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