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Boxcar
| | Posted on Sunday, February 08, 2004 - 5:46 pm: | 
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I have a question here and I'm stumped! I recently acquired a used rci 2980(older model) off of ebay and when trying to figure out a few issues with low swing on the am side I found the following. Both variables for am modulation and am low power do not change while adjusting these so that got me wondering if anything's been clipped(audio limiter)and found nothing has been cut. In trying to troubleshoot this low am problem, I went ahead and cut the r249 resistor and found no change in the swing either. I can set the deadkey at 2 watts and it swings no more than 15 tops. Both finals (2312's) are fine also. Trying to adjust the ferrite pod that changes your power didn't really help either. I did notice also that there is a 1N4005 diode that was put in that is a typical mod done on this but right off hand I don't remember which number it was but my tech told me it's supposed to lower the deadkey and not change the swing. We changed this out to a different one and still no results on swing. Here's the catch though that we found. When setting the deadkey at 2 watts and got nothing more than 15 for swing, I turned up the rf power knob to a 10 watt deadkey and it shot up to 30 watts on the swing so I'm wondering why I can't get nothing on the lower side of setting a deadkey. Anyways, enough radio babble. I just thought maybe this might be something interesting for you guys out there! Thanks for any input on this!!!! |
Bigbob
| | Posted on Sunday, February 08, 2004 - 9:19 pm: |
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you're getting a 7to1 swing ratio I'd say that's pretty good 6to1 is perfect for driving an amp,I don't know why but I can get a 15 to 1 ratio with my 2517,well actually I do 307 is his username,but my eagle 2000 has the same board as your 2980 and it does the same as you stated,so you really don't have a problem,you could try replacing the 2sb754 mod.regulator with a heavier one,more current may mean more modulation if you can't get 100% now. |
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