[Elecraft] KSB2 Troubleshooting Questions

Sat Oct 4 15:51:01 2003

Hi Paul,

I had the same issue with my KSB2 as well. This is pretty much from Gary
at elecraft.

Paraphrasing, the first good and dirty test is to set up a dummy load
and an RF wattmeter in the RF output of the radio. Put the unit into CW
mode or tune and send a long, continuous signal. Note the power output
on the wattmeter, not the K2. Then, set up your K2 for SSB transmission
with a good mike, and FL1 on OP1 with the correct alignment of OP1. Key
the mike and give a loud, low pitched whistle into the mike. The RF
output with this maneuver should be at or close to the power output with
the CW note/tune. If it is in fact close, there's nothing wrong with
your SSB board; the filter is simply filtering. Since you are having
problems with both transmit and receive, it is unlikely to be your mike.

The next place to look (as ever) are the toroids. T1 and T2 must be
oriented correctly: green leads (going to the fewer turns) on the
outside of the board. Looking at the schematic, these are the impedance
matching transformers and any mess-up with these would be disastrous in
turns of signal strength. Good joints are critical, as they are for the
two wound inductors. After that, round up the usual suspects-I can send
you Gary's email in toto if it would be helpful

In my case, my board is fine. I'm still not happy with the audio volume.
The problem prodded me to optimize my OP1 alignment and I had my
daughter listen to transmissions as I spoke. When I sounded like myself
instead of Alvin the Chipmunk, we both were satisfied.

Good luck

Ed

AA1WZ K2/100 #3548

From: Paul Clay <[email protected]>

To: [email protected]

Date: Fri, 3 Oct 2003 01:25:09 -0700

Subject: [Elecraft] KSB2 Troubleshooting Questions

I installed my KSB2 this evening into my K2 ser 

3640.  Everything seems ok except that  my 

receiver senstivity seems a bit degraded, and 

maybe the volume's a bit lower.  E,g,, local AM 

station I was listening to today after installing 

the K160RX now, after installing the KSB2 now 

seems much weaker, as do signals on 40 meters.

As directed by the manual, I took some voltage 

readings.  Most readings are just about right.  

However,  U2-5 and U4-3 are reading about 6v 

(5.94v to be precise) instead of the 0.6v shown 

in the KSB2 manual's voltage table.  Are the 0.6 

table entries in the manual typo's?  The pins in 

question are connected (if I read the schematic 

correctly in the circuit to U1-2,; at U1-2, I'm 

measuring, as the manual's voltage table says I 

should measure, about 6 volts (actually, 5.94v, 

which I think is close enough).

As I said, every other voltage seems about right; 

FWIW, a lot of locations that are supposed to 

read 0v are actually reading somewhere between 10 

and 20 mv; other than that one location that's 

supposed to read 400mv is reading about 260mv - 

but I attribute these differences to the vagaries 

of my DVM.

Thanks in advance for any helpful suggestions.  

Maybe it (the apparent lower senstivity and 

volume) is all in my head or just reflective of a 

change in band conditions between late this 

afternoon and late this evening (tho that local 

AM station shouldn't be so different in signal 

strength.

- Paul, N6LQ

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