[Elecraft] Re: Help, I think I've killed my K1

[Morrow, Michael A.]

John Webster / N6JW wrote:

> I picked up a NTE988 regulator this afternoon from
> a local supplier...
> 
> Well, the LED's come on, the relays clicked and the LCD
> read the band and frequency.  So far so good.  An antenna
> soon proved the RX was working, with sweet CW on 40m.
> I have not tried to transmit.  For I quickly began to find
> anomalies occurring:  1. A distinct hum on each press of the
> front panel press-switches; 2. An internal volt-meter that now
> displayed the battery pack voltage as 14.4volts!; 3. And
> eventually I found that pressing the "switch filters" button
> caused the MCU to go into hang up mode.  I can switch
> off and on again and it comes to back to life.
> 
> So it seems that Bob was EXACTLY right.  The 6.2 volts
> of the NTE988 causes some spooky stuff to happen with
> the MCU.  So it seems that I will just have to wait to get
> a proper ZR78L06C from Elecraft or elsewhere.

I've got to congratulate Bob/AG5Q on his call on this.  A really high level
of skill and knowledge is apparent!  I'd have thought it unlikely that a 0.2
vdc increase in regulator output would produce that sort of behavior from
the 16C77 PIC.  I thought it might have some effect on the digital voltmeter
indication, but likely little else.

John, did you happen to measure the output of the NTE-988 to see exactly
what its output voltage was?  I wonder if it was even higher than its
nominal 6.2 vdc.  (Never mind if you didn't.  I know it's hard to access the
PCB around the regulator.)

73,
Mike / KK5F