Scope Probe for 0.40mm Pin Spacing

[Harry Dellamano]

So I am struggling with the above problem. I am comfortable with the normal
pointed scope probe on 1.00mm spaced pins but 0.40mm are a PITA. There must
be some fixture that can be mounted and control XYZ to make a adequate
connection to the pin for probing. No, there are no thru holes or components
available that help probe these pins.
Thanks, Harry

 

[Joerg]

So I am struggling with the above problem. I am comfortable with the
normal pointed scope probe on 1.00mm spaced pins but 0.40mm are a PITA.
There must be some fixture that can be mounted and control XYZ to make a
adequate connection to the pin for probing. No, there are no thru holes
or components available that help probe these pins.

For me the solution (so far) always came from my wife's stuff: A sewing
needle. I even had my own from before we married but I wore those out.
Not so much from sewing but from scraping and probing around electronics.

 

[Nico Coesel]

So I am struggling with the above problem. I am comfortable with the normal
pointed scope probe on 1.00mm spaced pins but 0.40mm are a PITA. There must
be some fixture that can be mounted and control XYZ to make a adequate
connection to the pin for probing. No, there are no thru holes or components

I solder thin wires (connected to a header) to such pins.

 

[TTman]

So I am struggling with the above problem. I am comfortable with the
normal pointed scope probe on 1.00mm spaced pins but 0.40mm are a PITA.
There must be some fixture that can be mounted and control XYZ to make a
adequate connection to the pin for probing. No, there are no thru holes or
components available that help probe these pins.
Thanks, Harry

I use 'Takaya' probe pins... micro point, super sharp and will go through
conformal coating

 

[Syd Rumpo]

For me the solution (so far) always came from my wife's stuff: A sewing
needle. I even had my own from before we married but I wore those out.
Not so much from sewing but from scraping and probing around electronics.

A small hypodermic syringe works well too, the needles are very sharp
and the syringe body makes a handy insulated 'handle'. 0.5ml types used
for insulin are good. Difficult to solder, but the hollow needle will
readily crimp onto a thin wire.

Actually, these are good for all sorts of things, including using them
as miniature crowbars to lift component legs for debugging or complete
part removal. I have dozens from a deceased relative.

Cheers

 

[Joerg]

A small hypodermic syringe works well too, the needles are very sharp
and the syringe body makes a handy insulated 'handle'. 0.5ml types used
for insulin are good. Difficult to solder, but the hollow needle will
readily crimp onto a thin wire.

Actually, these are good for all sorts of things, including using them
as miniature crowbars to lift component legs for debugging or complete
part removal. I have dozens from a deceased relative.

I often use syringes in my work, mostly for oiling difficult to reach
shafts, pressure tests, et cetera. Like when the input attenuator shaft
on a scope seized up. Once when I wanted to buy syringes at a drug store
the pharmacist looked at my arms (I wore a T-shirt). "No, not for that
kind of stuff"

 

[Lasse Langwadt Christensen]

So I am struggling with the above problem. I am comfortable with the normal

pointed scope probe on 1.00mm spaced pins but 0.40mm are a PITA. There must

be some fixture that can be mounted and control XYZ to make a adequate

connection to the pin for probing. No, there are no thru holes or components

available that help probe these pins.

Thanks, Harry

I imagine sliding something like two pieces of thin plastic between pins
on either side of the pin to be probed could work

or maybe a piece of flex pcb slid in between pins, on side connect to pin
the side other isolated

-Lasse

 

[Dimitrij Klingbeil]

So I am struggling with the above problem. I am comfortable with the
normal pointed scope probe on 1.00mm spaced pins but 0.40mm are a PITA.
There must be some fixture that can be mounted and control XYZ to make a
adequate connection to the pin for probing. No, there are no thru holes or
components available that help probe these pins.

Sunhayato in Japan makes some test clips for that kind of parts. The FP-7S
clips are for parts of 0.3-0.5mm lead pitch (0.3mm nominal, allows some
additional distance to each other). For details see
http://www.sunhayato.co.jp/products/details.php?u=873&id=04046 (in the
picture it's the set of locked-together tiny clips to the left of the QFP).

Sure, they are not scope probes, but they have connection leads with
pin-header type sockets at the end, so one could rig a connection to an
existing scope probe without many difficulties.

The prices however are in the "run and hide" range. A set of 2 clips
(FP-7S-02) goes for the equivalent of 60$, a set of 10 with 2 holders
and a loupe (FP-7S-10) will set you back about 300$.

They also have a 3GHz version of the 0.3mm pitch clips, complete with a 3mm
length lead and connection to attach a scope probe (FP-HSP10S1). From the
picture, the connection lead on these looks really fragile, even by a very
careful Japanese engineer's definition of "fragile", and their idea of
"affordable" is around 70$ for one Signal+GND clip pair. The 1GHz version
(FP-HSP15S1) looks more rugged in comparison, at least in so far as "rugged"
applies to something with spring contacts in the 2-digit microns, that is.
There's also a 5GHz version, with no leads at all, but I'm not sure, what
one would need to even make proper connections to it. Coax hardlines with
0.8mm diameter maybe, if any such exist.

Well, maybe Joerg's sewing needle idea is still the best one after all,
and if no sewing needles happen to be nearby, there's still the option
of taking one strand out of a bicycle brake cable, crimping it into a
thin copper tube except for 2-3mm at the end and sharpening the business
end of it to any needed diameter. 100 micron or so should be possible.

Regards
Dimitrij