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Post by Marc on Apr 16, 2010 13:56:12 GMT -5
Well now that the power switch is in place I have found the first and hopefully only issues.
Seams that no mater how low I set the dk on a RMS watt meter
when modulated the meter shows reveres modulation.
On a peak meter it shows only about 3 watts forward swing
2 watts dk swings to 5 watts.
Any thoughts
Marc
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Post by Tombstone (R.I.P.) on Apr 16, 2010 16:48:31 GMT -5
Try peaking the RF power up to about 3/2 to four watts. If it won't do that you probably have bad final or final driver. If you can get the power up you'll probably see more modulation "swing". That's as long as the modulation circuit hasn't been butchered. There may be other issues but that's where I'd start.
Tombstone
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Post by Marc on Apr 16, 2010 16:59:58 GMT -5
Thanks I will try that
Marc
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Sandbagger
Administrator/The Boss 
Posts: 6,247 
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Post by Sandbagger on Apr 17, 2010 20:03:16 GMT -5
Well now that the power switch is in place I have found the first and hopefully only issues. Seams that no mater how low I set the dk on a RMS watt meter when modulated the meter shows reveres modulation. On a peak meter it shows only about 3 watts forward swing 2 watts dk swings to 5 watts. Any thoughts Marc How much power does it put out on SSB? If that too is low, then it's either badly misaligned, or I'd agree with Tombstone that a final is possibly weak. If SSB power is normal (18- 20 watts with the ALC opened), then it's more likely a problem with the AM modulator/regulator circuit, possibly a swing mod gone horribly wrong........ |
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Post by Marc on Apr 19, 2010 12:06:10 GMT -5
Yes ssb power is not up to snuff pushing the audio hard will get about 12 watts but is very touchy. I would say it is the finales also as there have been on mods done to the radio other than standard ch expansion and r131 changed to a 47-50 K resistor
When I checked the bias it was very high on both driver and finale.
Radio was taken to Shop.
Marc
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Sandbagger
Administrator/The Boss
Posts: 6,247
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Post by Sandbagger on Apr 20, 2010 8:30:22 GMT -5
Yes ssb power is not up to snuff pushing the audio hard will get about 12 watts but is very touchy. I would say it is the finales also as there have been on mods done to the radio other than standard ch expansion and r131 changed to a 47-50 K resistor When I checked the bias it was very high on both driver and finale. Radio was taken to Shop. Marc 12 watts is a little low, but not low enough to suspect a bad final. I would suspect that the radio just needs a good tune up, especially if the bias settings have been screwed around with. Sending it to a (hopefully good!) shop is probably a good idea. They'l hopefully straighten it out. |
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