ivp wrote:
>> I guess the only other thing I can try before replacing the PIC is
>> to add some debugging pin code, maybe to the UART ISR for
>> starters
>>    =20
>
> How about disconnecting the receiver until the PIC has stabilised,
> or something like that. Might help identify where the problem really
> is
>  =20
I'll give that a go tomorrow. The receiver output is full of random=20
noise when idle, but it is the same on all boards.

As for power, there's not much to the circuit. A 12V battery via a=20
1N4007, into a 78L05 with a 100uF on the input.

What's really odd about this is that replacing the chip fixed the=20
problem on the first faulty unit. Apart from those two units, all the=20
others work well.

I'd bet money that replacing the PIC will solve the problem, but I'd=20
really like to know why before I do that. Since it is a TQFP package,=20
swapping them back and forth not an option.

I do have brown-out detect enabled IIRC. The only other idea I have is=20
that the power-up timer is bad on some chips. Seems unlikely though.
David...

--=20
___________________________________________
David Duffy        Audio Visual Devices P/L
Unit 8, 10 Hook St, Capalaba 4157 Australia
Ph: +61 7 38235717      Fax: +61 7 38234717
Our Web Site: www.audiovisualdevices.com.au
___________________________________________

--=20
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