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PostPosted: Mon Sep 24, 2012 11:12 am 
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Joined: Thu Aug 09, 2012 6:16 pm
Posts: 43
Hey Jim,

I started documenting the changes (ECOs) per the list on you google site. Not sure I have them all and where (E.G. which end of the trace) they should go. I just spotted this morning that the board bottom photo on your site has most of the changes visible. I took the liberty to mark and crop some things and hopefully you will be kind enough to help me set it all straight.

U8 pin 15- choke needed? Value?
3 100R resistors on U9 needed? Value?
TX_10 choke- I guess it is obscured by the heatsink in photo.
Caps on encoders needed, value?

Which trace end is better for the chokes? Closer to the amp, or closer to the digital side?


Attachments:
File comment: There appear to be some caps on the Encoders and three 100 Ohm resistors on U9- I added the 100nF cap across pins 7 and 13 as it seemed a shorter path.
U9_and_encoders.jpg
U9_and_encoders.jpg [ 106.93 KiB | Viewed 10370 times ]
File comment: Chokes added- did not see TX_10
Chokes_added.jpg
Chokes_added.jpg [ 51.5 KiB | Viewed 10370 times ]
File comment: These are the caps across the band relays- I mounted mine across the diodes topside, OK?
Caps_across_relays.jpg
Caps_across_relays.jpg [ 59.18 KiB | Viewed 10370 times ]
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PostPosted: Mon Sep 24, 2012 2:12 pm 
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Joined: Mon Jul 23, 2012 6:25 am
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U8 pin 15- choke needed? Value?

That's the TX line and it definitely had RF on it from the PA so if you aren't building the off-board PA you will need this choke. Select a bead which has high impedance from 20-60 MHz.

3 100R resistors on U9 needed? Value?
I think the only one that's needed here is the pull-up on pin 1 any value 1K to 47K without it the processor stays in reset. The other two resistors provide midpoint bias for an A/D pin but I seem to remember that they weren't needed. They look like 1Ks.

TX_10 choke- I guess it is obscured by the heatsink in photo. Yup, bound to be in there somewhere.

Caps on encoders needed, value?
If you are using mechanical encoders these are needed for debouncing, 0.1 uF.

Thanks for capturing this.

73's
Jim WA2EUJ


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PostPosted: Mon Sep 24, 2012 11:00 pm 
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Joined: Thu Aug 09, 2012 6:16 pm
Posts: 43
jimveatch wrote:
U8 pin 15- choke needed? Value?

That's the TX line and it definitely had RF on it from the PA so if you aren't building the off-board PA you will need this choke. Select a bead which has high impedance from 20-60 MHz.


How does 428 Ohms at 50MHz, 350 mOhms DC resistance, and 300 mA in a 0805 package sound? Should be OK? Fair-rite 2508056017Y0 Datasheet http://www.farnell.com/datasheets/908867.pdf and
product page http://www.mouser.com/ProductDetail/Fair-Rite/2508056017Y0/?qs=%2fha2pyFaduhufI1123ku7xkh0WnrLuge9wBRznNfqKP%252bn40q6mE3nw%3d%3d


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PostPosted: Tue Sep 25, 2012 10:09 am 
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Joined: Mon Jul 23, 2012 6:25 am
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That sound like an excellent ferrite!

Jim.


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PostPosted: Mon Oct 01, 2012 10:10 am 
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Joined: Thu Aug 09, 2012 6:16 pm
Posts: 43
If you do not see "S" on the bottom right corner after boot up- you need to add the pull-up resistor pictured above on U9.

I found the cause for the S-meter not showing - it was the DSPic33 staying in reset. Doh! - I forgot to put the ECO pull-up resistor on the board from Pin 1 to 18 of U9! I used a 1K2 for a pull-up. I will cross post this to the ECO thread. Some progress now.


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PostPosted: Mon Oct 01, 2012 10:13 am 
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Joined: Thu Aug 09, 2012 6:16 pm
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One more thing- the caps can be on the main board for the PBT encoder- but not the VFO encoder or you will not be able to use the ICSP port! Put the caps on the encoder end so when you remove the encoders for programming they are not in circuit.


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