Bit Rot

That old bug that Vik discovered in the stepper routines that caused
the Y axis to move somewhere but not the X (it only showed up in the
"return to origin while cooling" code) has now spread to disrupt
everything :-(

However, this is not as bad news as it sounds, as at least now I'll
have to fix it properly rather than doing a workround. I have dark
suspicions about the way the sync pulses work combined with the new
Universal board...

Best wishes

Adrian

Dr Adrian Bowyer
[staff.bath.ac.uk]
[reprap.org]
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Wow! Sounds nasty! Good luck chasing the bug(s) that are causing that down.

Dark suspicion confirmed, but it was a simple, if subtle, hardware bug: if you wire the Universal for stepper control it doesn't need the thermistor resistor R3. But one end of R3 also forms a via for the sync pulses...

Given the similarity of the problem to Vik's return-to-zero-for-cooling bug, I'll start looking in the sync code for that too.

so what is the solution? do we leave out R3? we'll need to update
the build instructions.

On 26 Mar 2007 02:54:02 +1200, RepRap Forum Mailer wrote:
> Author: Adrian Bowyer
> Username: Adrian Bowyer (80-45-23-196.static.dsl.as9105.com)
> Subject: Re: Bit Rot
> Forum: Developers
> Link: [forums.reprap.org]
> Approved: Yes
>
> Dark suspicion confirmed, but it was a simple, if subtle, hardware bug: if you wire the Universal for stepper control it doesn't need the thermistor resistor R3. But one end of R3 also forms a via for the sync pulses...
>
> Given the similarity of the problem to Vik's return-to-zero-for-cooling bug, I'll start looking in the sync code for that too.
> _______________________________________________
> Developers mailing list
> Developers@reprap.org
> [reprap.org]
>
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Quoting Zach Hoeken :

> so what is the solution? do we leave out R3? we'll need to update
> the build instructions.

If you're building an extruder you put R3 in; if you're building a
stepper controller you replace the right-hand end of it with a via. A
commercial board will be through-plated of course, so the problem then
goes away. But for homebrew it's significant.

All the build instructions need to be updated extensively for the new
designs anyhow; I'll have a hack at that in a day or so.

Best wishes

Adrian

Dr Adrian Bowyer
[staff.bath.ac.uk]
[reprap.org]
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On Sun, 2007-03-25 at 15:40 +0100, Adrian Bowyer wrote:
> That old bug that Vik discovered in the stepper routines that caused
> the Y axis to move somewhere but not the X (it only showed up in the
> "return to origin while cooling" code) has now spread to disrupt
> everything :-(

I must admit to having commented it out here.

Vik :v)

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