I got my 3M 28-pic SOIC test clip last week and finally
got a chance to check it out.  EXACTLY as you described.

I do need to be aware of ensuring I don't push the SOIC
chip all the way to the PCB when soldering it.  And yes,
the force of the spring is very high.  I did remove it
easily (pushed the hinge pin out), but decided not to
mess with it till I've tried it -- I was worried about
the force it would exert on the SOIC pins, but it seems
that the force is really exerted on the body of the SOIC,
as the test-clip pins are also "springy".

What's nice is that I can grip an SOIC really easily
with this when it's OFF of the PCB -- so I won't need
to solder it in first.

Think we have a winner.

Thanks,
-Neil.





-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Brett Walach
Sent: Sunday, June 02, 2002 5:18 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [PIC]: Anyone used this device before?...


> 3M SOIC Wide Test Clip, 28-Pin, Alloy (923660-28).
> Can't find a picture anywhere on digikey's site nor
> 3M's site.
>
> This is (allegedly :) a test-clip that will clamp
> around the pins of an SOIC chip.  I'm thinking of
> using it as a simple way to program 16F872-I/SO
> chips.  I'll solder the chip in first, clip this
> on (with the appropriate wiring to my Tait
> programmer), slap the code on, and build the rest
> of the circuit.

Hi Neil,

We use these at work with our Promate II and a 28 pin DIP socket adapter (3M
clip -> 5 ICSP wires -> 28 pin DIP socket -> Promate II's 28 pin DIP socket
adapter). They work good for low current (Vdd) applications, but they also
have some issues. The force of the clip is extremely high...I've often
thought of removing the spring and cutting a 1/4 coil off of it. The clip is
designed to grab between the pins on an SOIC part and grab the under side of
the plastic body. Unless you use a minimal amount of solder on the pins of
the IC, the clip has a tendency to "pop off" due to it not being able to get
between the pins and under the part. If this happens, you can still use
it...you just have to hold it on there. There are wirewrap pins on the top
of the clip, which is also where you press to open it. Due to the high force
of the spring, they tend to dig in to your fingers. And if the clip wants to
pop off you also have to press down with an equal amount of force to keep
the clip on the pins.

Bottom line is, this clip is a good solution. You just have to baby the clip
(and your fingers) to get it to work properly.

Sincerely,
Brett Walach

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