[rp-ml] Problem with SLA 250/50

Jan Andrzejewski taikojan at gmail.com
Mon Feb 19 18:40:09 EET 2018

Here's the reply from my Old SLA maintenance friend.

"Assuming the problem happened to a good working machine, and not one which
had hardware or software changes when it happened, I would start with the
interlock at the door itself which is accessed via a cross head screw near
the door latch, the limit switch there can be forced back and not close

Also advice from Jim McMahon seems like good maintenance checks as well.


On 19 February 2018 at 16:23, Jim McMahon <jim at layergrownmodel.com> wrote:

> The clues to pay attention to:
> The machine is 1995 vintage. 23 yrs old.
> The problem began during a build.
> The machine uses an older electro-mechanical hard drive.
> The door open data is checked consistently for safety reasons.
> The door open jumper changes the voltage on a component to indicate an
> error. Any break in the door open circuit will trigger this error. (
> Voltage level change) Voltage is normally 5 vdc at connector when door is
> open. Shunting connects it to circuit common and so current is passing this
> this all the time.
> 5 volt DC supply could be too low. The wiring connectors back to circuit
> board may be oxidized from 20 years of heat. The hard drive may need to be
> scanned for bad storage bytes. Or the component on the board may have
> failed. Check each item until you find problem.
> On Feb 19, 2018 1:55 AM, "Solid Concepts" <prototype at solid-concepts.com.au>
> wrote:
>> Good morning Rapid Prototyping Community,
>> I hope you are all well and that perhaps someone can help me solve a
>> problem related to an SLA. I have an SLA 250/50 from 95.
>> The machine has been upgraded with a solid state laser and was working
>> perfectly well until, during a built, it stopped with a
>> message saying that the door was open. Impossible to restart the machine,
>> during the rebooting the same message shows up.
>> I have checked the cables and even closed the connection making a loop at
>> the switch, all to no avail. The operating system is
>> DOS I have even tried another VAT controller but the same message comes
>> up, "door is open, please shut door to continue"!
>> Can someone please help me resolve this problem? Do you have any
>> suggestion as to what could cause this anomaly?
>> Thanking you in advance.
>> Kind regards
>> Francois Primon
>> Director
>> Solid Concepts Pty Ltd
>> Unit 17, 64-66 Bannister Road
>> Canning Vale WA 6155
>> www.solid-concepts.com.au
>> Tel: (08) 9455 5377
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