K60XV are you tired of this yet?

[John Wiener]

Don, if I spent the appropriate amount of time thanking you, I'd  
never get anything else done.  Nevertheless, THANKS.

Here's where I am with the K60XV.  I find a short between pins 7 and  
8 on P1.  A 15X loupe shows NO solder bridge.  Topside, the spacing  
between P1 and Q1 is very close and at that point I can't completely  
follow the trace.
But, the schematic shows the trace going to Q1 emitter and the board  
shows the trace going past Q1 emitter and thru a "pass-thru" to pin 4  
of U1.  I read zero ohms throughout this trace (the 6VDC line).
On the bottom of the board, there is no trace for pin 8 (the 6VDC line).

I replaced R1 and C12 a while ago.  Now, with both of those installed  
(and U1 removed) I get OPEN reading between pins 13 and 14 of U1  
socket.  My thinking is that since C12 is in place, the short is  
between C12 and P1.
Does this sound logical?  That means that P1 is the likely culprit.

If so, I fear destroying the board while removing P1 (and also  
destroying Q1).

If past experience is any guide, my thinking is probably way off the  
mark.  So it goes.

Have I said thanks yet?

John
AB8O
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[Don Wilhelm-3]

John,

Since you find open circuit between the U1 socket pins 13 and 14 with U1
removed, that is good - it says the short is NOT on the board.  The short
has to be inside U1!  If the output resistor on the pin 13 output inside the
chip was shorted it would connect pin 13 to Vdd (pin 14).

So -- you will need a new K60XV firmware chip.  Time to send an explainatory
note to [hidden email].

73,
Don W3FPR


> -----Original Message-----
>
> I replaced R1 and C12 a while ago.  Now, with both of those installed
> (and U1 removed) I get OPEN reading between pins 13 and 14 of U1
> socket.  My thinking is that since C12 is in place, the short is
> between C12 and P1.
> Does this sound logical?  That means that P1 is the likely culprit.
>
>

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