Melzi trimpot value

Well, I've managed to twist the top off one of the trimpots on my Melzi board.

Does anybody know what value they are?

I suspect I need to change all four as they are all very stiff - is this normal.

Thanks,
Mark

Hi Mark

I've just managed to take the head off of one of the trimpots on my Melzi commissioning my reprap.

Did you ever manage to find out what they were?

Mine are small silver pots which are very stiff, this is what lead to the head being broken, slightly too much force me thinks. :-(

Phil

Hi Phil,

No, I'm afraid I didn't - RepRapPro replaced mine and the new one has different trimpots.

Looking at the schematic (http://www.reprap.org/mediawiki/images/f/f1/Melzi-schematic.png) it's taken positive (which I think is 5v) by a 20k resistor and the RepRapPro instructions are to trim it for 0.4 volts which happened at a little less than half rotation so I'd guess it's 5k (assuming a reasonably high impedance on the A4988s reference pin).

Or if you're going to replace them then I suppose you could just unsolder one and measure it :-)

Good Luck,
Mark

10K on mine.

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