DW,
First, the 7808 will work, but the stock regulator is a low dropout
type, so if you replace it with a 7808, the power supply voltage that
will create proper operation will have to be a bit higher. That may
make no difference if you are operating from a home station power
supply, but if you are operating from a battery, the battery low voltage
that will cause improper operation will be higher than with the low
dropout regulator. I suggest requesting a replacement regulator from
Elecraft - [EMAIL PROTECTED]
The low 8 volt supply voltage will not cause an MCU failure - you have a
different problem there. Check the component values and check the
soldering. When you are finished, check the soldering.
73,
Don W3FPR
DW Holtman wrote:
Hello,
I posted this a few days ago. I will cut and paste here again.
""I'm in the middle of building a K2, S/N 6412.
While doing the Alignment and test Part 1, I had a couple of readings that
were not in specs.
1. Page 48, Setting the AGC Threshold, the manuals calls for adjusting R-1
for a reading of 3.80VDC on pin 5 of U2. The highest R1 would adjust to is
3.60VDC.
2. Page 48 Bargraph Current test. The manual calls for a current reading of
0.16 to 0.18. My K2 reads 0.25 amps. That is quite a bit higher than what is
called for.""
I received suggestions to check the voltage on the 8 volt regulator in the
control board. It is just as suggested, the voltage is almost 1/2 volt low.
Will a 7808 work? Is it the same as a LM2930T-8? They both have the same NTE
cross reference and are available locally.
I finally got around to reassemble for alignment part II. Some times, when it
turns on, nothing happens, no display on the LCD, none of the controls do
anything. After I turn it off and on a couple of times, it starts working as it
is suppose to. This also happened in the first section for alignment where I
had the problems listed above, I thought it was the memory initializing. This
is not the case, it is still doing the same thing. Would the low 8 Volts cause
the MCU to hang up?
Thank you for your help.
Best,
DW Holtman
WB7SSN
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