It's time to restore the 11/45.
tothwolf at concentric.net
Thu Feb 5 15:38:21 CST 2015
On Wed, 4 Feb 2015, Jacob Ritorto wrote:
> On Wed, Feb 4, 2015 at 10:00 PM, Jon Elson <elson at pico-systems.com> wrote:
>> The 11/45 has a row of little step-down regulator modules, all plugged
>> in with those horrible AMP Mate-n-Lock connectors. We often had bad
>> contacts on those and they would sometimes burn the connector housings
>> or char the ends of the wires. That was all about 1980, I can't
>> imagine they've improved with age. I think you may have more trouble
>> with these than anything else in the machine.
> I wonder if spraying out with crc contact cleaner and a nice slathering
> of dielectric grease would help.
Never use silicone (dielectric) grease anywhere near this sort of stuff.
Western Electric / AT&T learned the hard way back in the day when the
stuff damaged switch and relay contacts in their telephone switches. On
the other hand, something like Sanchem A-Special would be fine, although a
little messy. (And before someone asks, no, A-Special is not anything at
all like that nasty "Noalox" zinc particle garbage from Ideal
Industries...totally different product families and applications.)
The main issue with AMP Mate-n-lock connectors (and similar pin and socket
connectors from Molex) is the use of tin plated spring brass contacts
instead of tin plated beryllium copper contacts. Spring brass contacts are
not rated for very much current compared to beryllium copper contacts, but
manufacturers tend to buy whatever is cheapest. I've successfully used
both types of contacts for years without issues and haven't (yet) had the
catastrophic failures some people have described. If I use these type of
connectors for power though, I use beryllium copper contacts.
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