Results for Resistance Check on the Control Board

[Vic Dively]

Hello.  I've started building my first Elecraft, a K2.  My background in
soldering/kit building is thin, about 4 other kits, one of which actually
worked the first time I tried it out.  The others required a little
trouble shooting...

So I wanted a K2 bad enough to try building one despite all that.  I've
done the Control Board, and my resistance checks show some problems, I
think.  I've reviewed the solder joints and all the parts are there.  I
saw where the "greater than 100K" may show up as infinite...  even given
that, it looks like I may have a problem with U6.  Here's what I have:

Test Point   should be   my reading
P2 pin 1        >10K         1.51 M
U5, out         >2K          3.74 K
U4, OUT         3-7K         4.6 K
Q1 collector    > 1M         3.71M
Q2 collector    > 1M         3.8 M
U3 pin 8        > 10K        196K
U6 pin 13       >100K        open
U6 pin 14       >100K        open
U6 pin 29       70-90K       3.7K
U6 pin 30       70-90K       short
U8 pin 2        >100K        open
U8 pin 15       >100K        open
U8 pin 16       >100k        open

I see where more control board tests follow building the front panel.  Do
I have a problem that should be resolved now, especially the U6 pins 29
and 30 problem, or is it easier to trouble shoot at the next stage?

Thanks

Vic KG4HTT

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[Don Wilhelm-2]

Vic,

There is not much on the Control Board that connects to pins 29 and 30 -
these are the DOT/PTT and DASH lines and they connect directly to pins 17
and 18 of P3 (they also connect to 2 resistors of RP4).

Check carefully for any solder bridges at the pins of P3, the U6 socket and
RP3.

If you suspect U6 itself, you can remove it from the socket and check the
resistance on the board itself (you should see a high resistance similar to
the values indicated in the manual) - use static protection when inserting
and removing U6, and put it into the black anti-static foam (or the
antistatic tube) when it is removed.

73,
Don W3FPR

Life is what happens when you are making other plans
----- Original Message -----
From: "Vic Dively" <[hidden email]>
To: <[hidden email]>
Sent: Wednesday, June 16, 2004 9:03 PM
Subject: [Elecraft] Results for Resistance Check on the Control Board

>
> Hello.  I've started building my first Elecraft, a K2.  My background in
> soldering/kit building is thin, about 4 other kits, one of which actually
> worked the first time I tried it out.  The others required a little
> trouble shooting...
>
> So I wanted a K2 bad enough to try building one despite all that.  I've
> done the Control Board, and my resistance checks show some problems, I
> think.  I've reviewed the solder joints and all the parts are there.  I
> saw where the "greater than 100K" may show up as infinite...  even given
> that, it looks like I may have a problem with U6.  Here's what I have:
>
> Test Point   should be   my reading
> P2 pin 1        >10K         1.51 M
> U5, out         >2K          3.74 K
> U4, OUT         3-7K         4.6 K
> Q1 collector    > 1M         3.71M
> Q2 collector    > 1M         3.8 M
> U3 pin 8        > 10K        196K
> U6 pin 13       >100K        open
> U6 pin 14       >100K        open
> U6 pin 29       70-90K       3.7K
> U6 pin 30       70-90K       short
> U8 pin 2        >100K        open
> U8 pin 15       >100K        open
> U8 pin 16       >100k        open
>
> I see where more control board tests follow building the front panel.  Do
> I have a problem that should be resolved now, especially the U6 pins 29
> and 30 problem, or is it easier to trouble shoot at the next stage?
>
> Thanks
>
> Vic KG4HTT
>
> ________________________________________________________________
> The best thing to hit the Internet in years - Juno SpeedBand!
> Surf the Web up to FIVE TIMES FASTER!
> Only $14.95/ month - visit www.juno.com to sign up today!
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> http://mailman.qth.net/mailman/listinfo/elecraft
> You must subscribe to post.
> Subscriber Info (Addr. Change, Unsub etc):

http://mailman.qth.net/subscribers.htm
> Elecraft page: http://www.elecraft.com
>


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