[Elecraft] K2 Assembly problems/Info 080 Message

[Don Wilhelm]

Tom,

I suggest we get the resistance readings straight before applying power.

Were the resistance readings made with the boards separated? They should 
have been.

First check Control Board U3 pin 8 (with the board removed). Is 1.009 
mean 1.009k or 1.009M?  If your DMM is autoranging, you will have to 
look at the range that was selected to tell the difference. 1k is not 
good, but 1M is just fine.
The ">" symbol means "greater than" and any reading above the listed 
value is just fine.
If the resistance there is 1k, then look carefully for solder bridges.  
You may have to wick away any excess solder.
Solder just sufficient to fill the thru-plated holes is enough.  If your 
solder connections have a convex appearance, that can hide a poorly 
soldered joint.  A small concave solder fillet is OK.

All the resistances on the RF board appear to be OK *if* the range for 
those readings is kohms.

On the front panel, J1 pins 10, 12, 15, 16, 17, 18, and 19 should be 
resolved before proceeding with anything else.
Did you have the control pots all set to mid-range before taking the 
readings.  If the RF gain is not set to mid-range, that can explain the 
low resistance reading, otherwise, begin looking for solder bridges.
I am suspicious of the resistance readings on pins 10, 12, 16, and17.  
Those are digital signals and you would have no display at all if pin 12 
is really grounded.
Front panel J1 pin 18 is the 5 volt supply to the front panel board - 
again, if that resistance is really 25 ohms, you would be drawing a lot 
of current on the front panel and nothing is likely to work.
Please recheck those resistances and please specify the units - ohms, 
kohms or Mohms.

We can get to the U1 (and Info 080) problem and the last character of 
the display after the resistances have been resolved.
With that many erroneous resistance readings. either there is a problem 
with your DMM or you have many solder bridges to resolve.

I suggest we take this troubleshooting off reflector.  It is getting too 
long and most builders will not be interested in the specifics of th 
troubleshooting steps.

73,
Don W3FPR

On 3/4/2013 11:14 PM, Tom Fuller wrote:
> Don, 'could not get a reading' means my multimeter showed 0.L (or infinity),
> I switched to a large 13.8 volt power supply-now screen reads 13.5v .04
> amps...I did some re-soldering again today and now most of the digits on the
> display light up completely except for the digit above the XIT on plastic
> display , now my u1 on rf board is not heating up anymore, but there is no 6
> volts on it, but the solder connections are good, here are the readings you
> asked for,
>
>