[Elecraft] [K1] [KNB1] Noise blanker not detected (three dashes ---)

[Bogdan - Constantin Lazanu]

Thanks Don, but I have already done these checks and mentioned the results in my first post on this list.

73,
Bogdan YO8SAW

> On 28 Nov 2016, at 02:32, Don Wilhelm <donwilh at embarqmail.com> wrote:
> 
> Bogdan,
> 
> I just returned from Thanksgiving holiday/vacation and saw your post.
> 
> The indication of "---" in the menu entry indicates that the 6R/AUX signal line is not allowing the KNB1 firmware to communicate with the K1 main MCU.
> 
> I would suggest you check the soldering of RF Board J1 pin 2 and also pin 2 of the mating connector on the KNB1 board.
> 
> Also check to be certain KNB1 R1 is 180 ohms and is inserted into the correct lead holes and well soldered.
> 
> You could try a continuity check between Front Panel J1 pin 8 and the KNB1 U1 pins 3 and 4 - the resistance should be 180 ohms if all is well.
> 
> Double check the orientation of KNB1 U1 - the label used often covers the device notch on those 8 pin firmware packages making it easy to insert backwards.
> 
> The trimmer on the KNB1 board will work whether or not the KNB1 firmware is working.
> 
> 73,
> Don W3FPR
> 
> On 11/26/2016 5:53 PM, Bogdan - Constantin Lazanu wrote:
>> Hello,
>> 
>> This is my first message to this mailing list, so please be gentle!
>> 
>> During the summer and autumn I built my first ever kit: the K1-2 (#3449) + KAT1. Everything worked surprisingly well (being a first-timer and all), I never had any problems. Until now. It seems that I failed in my “build-without-help” venture :)
>> 
>> A few days ago I completed building the KNB1 option and when I got to the “Initial Test” phase I noticed that in the menu, instead of HI/LO/OFF I can only see three dashes (---). The instructions say that the K1 firmware has not detected the noise blanker module and that a possible cause may be that the U3 was soldered in backwards. I assume that’s a mistake - there is no U3. Just a U1, and it’s soldered properly.
>> 
>> Some details:
>> 
>> - The K1 firmware is revision 109
>> - The KNB1 PCB is revision Cr
>> - U1 on KNB1 has a small paper label with “NB 1.02” written on it
>> - Turning the trimmer C2 on KNB1 does vary the band noise and received signal strength
>> - There is continuity from KNB1 U1 pins 3/4 to the front panel U1 pin 8 (6R/AUX) - around 182 ohms
>> - The voltage between KNB1 U1 pin 1 (VDD) and GND is 6.03V
>> - The voltage between KNB1 U1 pin 5 and GND is 5.59V (this is the 6V switch for the noise blanker)
>>