[Elecraft] KXB3080 problem

[Soaring Eagles]

OK, I really appreciate your quick response!

I forgot to mention that the 20B cap does have a peak (not too much, but 
about the same as before, but there's no peak on 20A or 40. Also can't hear 
a peak on 30A or 30B.

'D' and '5" are correct
The trace is cut (I thought I might not have done it, so I did it again. ;) 
But, if I check do a continuity check on both sides of the old trace, I get 
a short. I have not taken the time to check this against the schematic, but 
I did check it.

T2 is wound correctly and installed properly and it does look like the 
photos. I followed the directions for stripping the toroids, so I'm not 
sure exactly what you mean here. What unstripped lead length would be a bad 
thing? If you're thinking that one of the leads is shorting somewhere it 
shouldn't, it doesn't appear to visually.

Yes, the 'A' and 'B' wires are correct (quadruple checked).

I did check transmit into a dummy load and here's what I get on my OHR WM-2
80 meters: 2 watts
40 meters: 3.5 watts
30 meters: 5.0 watts
20 meters: 3.2 watts

battery voltage shows 14.1 volts

Interestingly, the same setup showed 5 watts out on both 40 and 20 prior to 
the KXB3080 installation.

And, as I was typing this, I decided to hook back up the antenna and see 
what I heard. Well, signals were booming in on 80. Went to each band in 
turn and was able to successfully peak the 40, 30, and 20 meter filters.

So, what did I do? Don't really know. Other than going over everything 
about 10 times (no kidding) and scraping gently at 2 solder points that may 
(emphasize may) have been shorting. They didn't really look like they were, 
but there was some flux and it was shiny in the light, so I scraped a 
little between them. Don't even remember which ones they were. But, they 
were in the L6 and R1 part of the KX1 board and prolly one of the 
resoldered parts or very close to one.

I'll complete the reassembly. I planned on taking this on a trip to TX this 
week and was sweating not having it done in time. Hopefully I won't undo 
what I did do.

Thanks to everyone for putting up with the bandwidth!

Many thanks and 72 to Don. At least having some plan of action kept me 
going when I might have just given up til I got back from my trip!

Jim, WD9HBC



At 05:00 PM 8/16/2006, Don Wilhelm wrote:
>Jim,
>
>One thing that will cause that problem is if the 'D' and '5' wires are
>interchanged - they should cross over each other (guess how I discovered
>that <G>)
>
>Did you make the PC trace cut on the KX1 board?
>Is T2 wound correctly and installed properly? - it should look like the
>photos.  Were the toroid leads properly stripped?  The unstripped lead
>length is rather critical in the KXB3080, but the proper lengths are
>indicated in the manual.
>Did you place the 'A' and 'B' wires as indicated in the manual? - they are
>mixed on the KXB3080 board, so the wire marked A on the KXB3080 goes to the
>B position on the KX1 board, etc.
>
>Have you checked transmmit yet?  If you get proper RF output, you can be
>reasonably certain that the Low Pass Filter is OK, but if you find no or low
>power on transmit, look at the Low Pass Filter for the problem.  The LPF
>(and the DDS) are the only components shared by both the receiver and the
>transmitter.
>
>73,
>Don W3FPR