GS15plus problem

[Sander_Sander]

Hello everyone, i have a GS15-plus that has a problem with cutting. As you can see in the picture it cuts some circles like it should and the middle one cuts weird. It does it completely random. Sometimes at the exact same spot if i cut a lot of copies, and sometimes at a different place.

I have used this machine since 1999 and it always ran fine, i used the same Omega Software since i bought it.
I tried to run it on a different com port, and on a different pc, problem remained. (My previous pc that was running the plotter died last week).
I tried to turn the FIFO buffers off, and lower the cutting speed but this does not matter. I ordered 4 pieces of L297 chips that control the stepper motors to see if this helped anything. (I had a similar problem twice with my Fastrack 1300 years ago and this one was revived by placing 2 new chips on the board so i thought to give that a try).
This morning i replaced the chips, and now sometimes the machine stops when cutting and makes a fast bleeping sound and the lights are flashing continuously. It did not do this with the old chips. It also did the beeping a minute after cutting a job when the machine was in idle.
Does anyone know what this can be or have a solution.

Best regards,
Sander

 

[Sander_Sander]

I just cut the job of 12x5 repeats twice without any problem. It is really weird.

 

[netsol]

is there residue built up on one of the cam surfaces?
is this a variation of the way the glue can build up around the pins screwing up registration?

a thorough cleaning and lubrication would be a great start, i don't see any way that a worn or stretched belt could contribute to that, but what moves your knife up and down?
i believe a solenoid? perhaps we are just "gummed up" and not getting full consistent travel?

sorry for the vague answer, when i go to the shop i will watch one of mine cut and add to this if i have a stroke of brilliance

 

[Sander_Sander]

sprockets are clean
the shaft where the head moves from left to right is clean and properly lubed. I do not use the tangential mode, only the swivel knife mode. It happens during cutting that the head makes a strange cutting path. Looks like it can not interpret the data correct.

 

[netsol]

it kind of looks like what the cnc people call tramming (cutter blade not perpendicular on all planes)

i am assuming (I COULD WELL BE WRONG!) that it is not electronic,) also, that the roller is in good shape

more like the blade doesn't go and stay at the same depth.

 

[Sander_Sander]

when the head is running to make the circle it suddenly goes in a completely different direction, i am using the swivel knife option, the blade will automatically adjust itself and will allways be tangential (the blade is placed freely to spin around in a holder that has a tiny ball bearing in it and rotates whichever way you move it). It is not a depth problem at all. With the swivel option the blade never comes from the surface, it drops at the beginning of the circle, makes the circle and then the head goes up again. This is much faster then the normal mode where the head needs to be turned to be at the right angle on the cutting path. With normal mode if you have to make a 90 degree angle the head needs to lift, rotate and dropped again. Swivel knife mode keeps the knife down and makes a tiny rotation with the knife on the spot to position it correctly for the next movement.

 

[netsol]

i don't have to tell you that these things NEVER cut in a way that makes sense.
you'll never say "yes, that's exactly how i would do it, cutting by hand.

STUPID QUESTION:

you are connected serial port, i assume

did someone change your flow control or the port it hooks up to?
if one device's flow control didn't match, you might be discarding part of the cut, explaining why we suddenly go in a different direction

 

[Sander_Sander]

it is connected to COM1 serial port, no changes are made to port or setting. No one has access to the machine but me.
I don't understand exactly what you mean with flow control. Is that the X-ON, X-OFF setting? If so this is set correct to the specs in the manual and has not been altered.

 

[Billct2]

Try disconnecting the cable and reconnecting. I remember some issue I had was caused by the data transfer and somehow that cleared the problem.

 

[Sander_Sander]

the cables allready have been disconnected several times due to moving and opening the machine. I also opened the connector that goes into the machine to see if a connector was loose.

 

[netsol]

it is connected to COM1 serial port, no changes are made to port or setting. No one has access to the machine but me.
I don't understand exactly what you mean with flow control. Is that the X-ON, X-OFF setting? If so this is set correct to the specs in the manual and has not been altered.

yes, that is flow control & there are at least 3 options, hardware, none, x-on/x-off

the file being sent is larger than the buffer that holds it (when these devices were built memory was very expensive) and flow control keeps us from losing data.
think of pouring paint from a five gallon can into a smaller more convenient container.

if no one touched the machine but you this is not the issue, but we have seen it happen

 

[Sander_Sander]

i understand that something like that can happen, the settings must be correct or it will do strange things (if it does anything at all). On my large plotter the buffer chip was damaged, and it did the same thing, it cut some lines ok, then goes weird with cutting.
I am going to replace the buffer chip, and i am no expert on this by any means, but maybe this one is damaged too. They are inexpensive and swapping them out is very easy.
I will order this one next week, maybe like the large plotter it will fix the error. If there goes something wrong while the machine is buffering (and that chip is broken) i think that it might cause the problem i have now.

 

[mjames]

Sometimes deleting the file and creating a new one does the trick. It has worked for me before. Worth a try.

 

[Sander_Sander]

hello mjames, i have tried that as well, making it new from scratch, but it also happens if i only draw an empty circle, squares have less problems, but objects with curves in it are more complex to make and then the motor has to do more alterations, and more risks of making a problem if something is wrong.

 

[netsol]

I just reread the entire thread...
Just to clarify
It doesn't happen ever time (?)
But it is always the middle circle (?) although not always the same position(?) like the hands on a clock

 

[Sander_Sander]

the customer orders a lot of different stickers, all with a slightly different text on it, ranging from 12 to 300 per type, but mostly around 24 to 56
Stickers are 22 mm to 45 mm.
so i print 12 on top of each other (roll is 380 mm and i can print up to 299 mm), and i enter as much repetitions as needed to get the amount.
one time the error with cutting happens at the same circle in the cut job, next time on a different place, next time almost the same circle, next time no problem at all, and next time only a minor problem
my large cutter had a similar problem like this, when the buffer chip was damaged due to a static problem, replaced them and ran fine again after

 

[Vassago]

Tbh you might be experiencing interference.. As it's a VERY old machine theres virtually a 100% chance that the electrolytic caps in the psu and other circuits have now started to fail - it's very common in vintage equipment - so you'll now be getting ripple in internal power lines which does affect the main board - also many newer machines (pc's, basically anything using power) use switched mode psus which can introduce noise into the mains input - a ferrite bead can reduce inbound noise, but replacing the caps isn't a particularly hard task, but there might be a "few".

 

[Sander_Sander]

Hi Vassago, thank you for your answer. I have ordered all the push in chips that i could find at the webshop that sold the buffer chip, those will all arrive next week. If this does not fix it i will look at the caps, i have replaced a cap on a monitor that stopped working, i can do that.
Where should the ferrite bead be placed? On the Com port cable?

 

[Sander_Sander]

i checked the surrounding of the plotter, the com port cable was hanging next to a 30 kg Infinity Floorstanding speaker. I have now moved the cable away from the speaker. I had a cable tv box that was giving problems when it was on top of a 80kg subwoofer once. Might be a long shot that this triggered the problem, but i can see if it helps by any means.

 

[Sander_Sander]

i checked the electro caps visually, but they are not bulging (can not see inside of it of course), but visual check is ok.