Wednesday, February 1, 2017

A very tight fit

I spent a few hours hunting around for a socket that would accept a row of pins on 2.0 mm centers. There are quite a few of them, but most are designed to accept small square pins, perhaps as wide as 0.66 mm. The pins on the Vacuum Fluorescent Display are 0.7 ±0.12 mm wide and only 0.18 mm thick. This would be trivial if I wanted to solder it directly to a PCB, but I'm not in a position to know what I need in the way of a final PCB yet, and I don't want to risk damaging the VFD by trying to removing it from a PCB.

I think I finally found one possibility: the Mill-Max 8114 series. This is a single-contact pin receptacle able to accept a pin up to 0.86 mm wide, while only being 1.65 mm wide itself. That would leave a 0.35 mm gap between pins. Not terribly wide, but wide enough to fit some sort of insulator between, if need be, to maintain spacing. Maybe a bit of heat-shrink tubing over each one? I'd hope that the centering action of the VFD's pins would make this unnecessary.

A second option is to simply solder some wires to the pins and plug them into the solderless breadboard for testing. The only bit that seems critical is the pin is connected to an on-display oscillator, which requires an RC circuit that needs to be connected close to the pin. For this I'd simply solder the resistor and capacitor directly to the oscillator pin.

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