PLL Problem after K2 upgrading Rev. A to B

[Gerald Eberle]

Hello All

My K2 Rev. A worked all the years very well. But as I have the parts for upgrading to Rev. B since long, I have now finally made the modifications, except the Thermistor board installation, and run into problems with the PLL. With CAL FCTR and BAND-, the reading is in range, but BAND+ flickers around 50khz. As soon as I move the VFO the reading is in range, but gets lost again after pushing BAND+ again. CAL PLL returns Info 232. Despite this problem, the K2 receiver works on all bands and modes with some clicks at rounds of 5khz while turning the vfo. While checking the voltages at R30 I have noticed that some readings are 0 Volt while changing mode and or band. Maybe X1 is faulty? All parts used are from the mod-kits sold by Elecraft and I have inspected the soldering more than once, but one never knows... Of course the K2 is now far away from really useful. Where should I start searching?
Many thanks in advance for any help.

Gerald, HB9CEY

K2 #488, KX1 #2203, KX3 #0433

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[Don Wilhelm-4]

Gerald,

Did you add the 10k resistors to RP2?  If you did, check the value of
RP2.  If it is 10k (last digits = 103), then the resistors should not
have been added.  OTOH, if RP2 is 100k (marked 104), the 10k resistors
should stay in place and you will have to look elsewhere for the problem.

73,
Don W3FPR

On 3/30/2013 6:17 PM, Gerald Eberle wrote:
> Hello All
>
> My K2 Rev. A worked all the years very well. But as I have the parts for upgrading to Rev. B since long, I have now finally made the modifications, except the Thermistor board installation, and run into problems with the PLL. With CAL FCTR and BAND-, the reading is in range, but BAND+ flickers around 50khz. As soon as I move the VFO the reading is in range, but gets lost again after pushing BAND+ again. CAL PLL returns Info 232. Despite this problem, the K2 receiver works on all bands and modes with some clicks at rounds of 5khz while turning the vfo. While checking the voltages at R30 I have noticed that some readings are 0 Volt while changing mode and or band. Maybe X1 is faulty? All parts used are from the mod-kits sold by Elecraft and I have inspected the soldering more than once, but one never knows... Of course the K2 is now far away from really useful. Where should I start searching?
> Many thanks in advance for any help.
>


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[Gerald Eberle]

Hello Don

Many thanks for the quick response and precise directions where to look for.
Yes, RP2 is 10k and after removing both10k resistors all went well with CAL PLL.
I had overlooked the note about the 100k RP2. My fault!
Again, your knowledge and help is great! Already thought that I have ruined my K2...

73 and a happy eastern time
Gerald HB9CEY

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