AW: [DSP-10] DSP-10 Completion

[David Garnier]

Hi Jess,

I work in an engineering lab and do this stuff at work, when I come
home I don't really want to screw around with this stuff, my patience
runs thin...

My method is to first carefully solderwick around the chip to
removing most of the solder from the pad to pin interface then lift
"one pin at a time."  It is laborious but the idea is to protect the
board at all costs.

It sounds like you succeeded working on your Sony, maybe this
might be of some help, let me babble on. ;-)

If you have a fine metal pick or a couple of fine thin sewing needles
do this.  Solder wick all around the chip carefully removing all of
the solder on the pad.  Re-heat the pin/pad (don't lay the iron tip on
the pad only on the pin,) quickly wedge your pick between the ic's
body and the heated leg - carefully press outwards -  the pin will
"untack" itself from the pad with a metallic "pop."  If you want to
work on more surface mount projects Weller makes a small heat
gun.  All of us tech's have one of these guys - it is amazing what you
can remove with this tool, one does not need a IR reflow station
for small work.

Good luck,

dave garnier

W4mvb@cs.com wrote:


> Hi Dave,
>
> Thanks for the information.  I haven't yet determined what happened to my
> unit.  It was working OK, I shut off the power to do something and when I
> turned it back on the was not working.  I did find a "whisker" from a coax
> shield laying over near pin 1 of the CPU but upon examination of the
> schematic Paul, HB9OMQ sent me I don't see a connection.  So far I have only
> checked continuity from pin 43 of the CPU to pin 33 of P3.  It's there but
> seems intermittent.  I may just have had bad connections with my probes.  I'm
> going to get a set of needle point probes before I try again.  I've already
> blown up one PLL chip trying to measure voltages with my current test leads.
>
> I changed a 100 pin chip in the front panel of a SONY receiver a few months
> ago but it was a struggle for me.  If the problem turns out to be the CPU I
> guess I will give it a try.
>
> Thanks again for the info.
>
> 73 de Jess - W4MVB
>
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