just found this concerning Carling switches
http://www.tonefrenzy.com/articles/Boost_Pedal.html
Featured Article :: A comparison of boost pedals :: by Ken Nossardi

Footswitches
One of the first things to go out in a pedal, as many can attest to, is the
footswitch - often, the weak link in the chain. This would appear to be
worth some attention especially considering the prices some of these units
command.

The SD, like many other pedals using the same Carling footswitches, had
footswitch operation problems. Oddly enough, another Z Vex unit this user
tested recently which used the same Carling switch, also had footswitch
operation problems. One manufacturer stated that ever since Carling moved
the production of their footswitches to Mexico (the Z Vex units had Carling
Mexico-produced switches), it appeared the quality of their footswitch
deteriorated. Geoffrey Teese of Real McCoy Custom wahs believes the move to
Mexico was more coincidental and might have more to do with the Carling
workforce knowing how to manipulate the proper manufacturing of a switch
with the machinery used. When Teese was using the Carlings in his wahs (he
is now currently using a switch from CIC), he reported that out of 10 wahs
produced he would have 6 replaced before shipping and over time the other
wahs with Carlings in them are being replaced one-by-one. Zachary Vex of Z
Vex commented, "The tooling they use to make them is getting worn out. Many
of us pedal-makers have complained, but it falls on deaf ears at
Carlingswitch. They just don't care... They know they have the corner on the
market and I've heard they refuse to improve the tooling, which is over 35
[40+] years old. I throw away about 10 per 100 as it is." Yet another
pedal-maker commented, "Out of 1000 switches about 50 were dead right out of
the box and another 50 failed after a short use. I sent them back and will
never buy or recommend them again." This would appear to be a rather high
failure rate for switches to encounter at the production stage not to
mention failures that occur in the field thereafter. A rather disturbing
thought and a frustrating experience when one is on stage in the middle of a
performance and the footswitch decides to act up. Recently, this user
auditioned a fuzz unit by an upcoming boutique pedal-maker that also used
Carling footswitches with operation problems. After reporting the switch
problem to the maker, he mentioned that out of 100 fuzz units produced this
was the only reported problem. However, for reasons unrelated to
reliability, this maker has changed footswitches to one used by many of the
other pedal-makers.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/