rci 2970n2

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479tx
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rci 2970n2

Postby 479tx » Mon Sep 09, 2013 8:00 pm

I found the post where Goldfinger told someone which caps to parallel with larger value non-SMT (modder beware of course) for the 2995 DX. I'd like to try something similar to open up the lower end of the TX of a rci 2970n2 (I'm using a Drake R8B as a separate receiver which already does 6k beautifully)

From the specs on the 2995dx (can't imagine the 2970n2 would be too terribly different, although I hear its a different board) is 400hz-5000hz on AM TX. 5khz for a high end isn't bad for stock. If you could just get the low end down to 75-100 or so...
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Postby 479tx » Mon Sep 09, 2013 8:02 pm

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Postby Goldfinger » Tue Sep 10, 2013 2:19 pm

Is the 2970n2 surface mount or discrete components like the 2950DX? I've never worked on one before.
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Postby 479tx » Tue Sep 10, 2013 3:39 pm

2970n2 = SMT.

I also have a 2950-dx (also SMT) that I'd feel less bad about "tacking" some 1uf caps across in the right spots to get the TX frequency down below 400hz a bit.

If anyone has the right locations :)
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Postby Dago 971 » Mon Jan 20, 2014 12:21 pm

Any update on this? I just acquired a 2970 myself and I would like to widen out both the receive and transmit.
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Postby Goldfinger » Mon Jan 20, 2014 1:23 pm

Sorry 479tx, I musta let this thread slip my mind back in September. If it's the same as a 2995:

Receive:

C87: change to a 1-2.2uF mylar or non-polar electrolytic
C47: make smaller for more highs.
C48: 1-2.2uF
C193: 1-2.2uF


Transmit:

C163: Change to a 10uF Tantalum (observe polarity)
C199 and C262: change to 2.2uF mylar
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Postby 479tx » Sat Jun 21, 2014 6:51 pm

To those that are curious,

You can (if you are careful, and have a steady hand) solder light weight poly or tant caps across the existing caps you're supposed to change (shorten the leads, and bend them like a U shape) with good results!

I didn't feel comfortable removing the existing SMT components but this works just as good.
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Postby Goldfinger » Sat Jun 21, 2014 8:43 pm

Yes, leaving the old smaller value caps doesn't hurt a bit in parallel with the larger replacements.
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Postby 426 » Wed Dec 02, 2015 1:41 pm

On the 2970N2 the di point would it be C199 or 262
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Postby Goldfinger » Sat Dec 05, 2015 1:11 am

262
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Postby 426 » Tue Dec 08, 2015 7:55 pm

Thanks
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