HELP!! VP540 Advancing while printing like crazy!

[Jim Hancock]

The numbers represent on-off readings from the lines on the encoder disc interrupting the beam from the sensor emitter. The readings from the 2 sensors - grit and motor - are synchronized to control the motor speed, based on the commands received from the mainboard-servo board path. You will see similar behavior from the linear encoder for the printhead carriage by running the Linear Encoder test in the print menu in service mode. It will go up as the head carriage moves across the printer and back down as it returns home. The G-ENC CHECK test should show changing sequential numbers as it runs.

 

[HCG]

Since the G-ENC check test doesn't change more than sometimes to 1 and then fails, what does it tell me to do next? The F-ENC always goes 4000-8000-12000-16000-0. Doesn't that mean the feed motor encoder is good and the feed motor?

 

[Jim Hancock]

As I suggested earlier, you need to change the feed motor next. If that turns out the feed motor is the problem, it's difficult to say exactly what is wrong with the feed motor, as it has several different parts internally that could malfunction. Keep in mind you are troubleshooting an uncommon problem that could have several different causes.

 

[HCG]

Ok, I'll order a feed motor from Digiprint tomorrow, I think they are about $400, maybe if that doesn't fix I can send it back. Thanks. After that I assume the feed motor board? I just took off the cable for the encoder sensor to the feed motor board and checked continuity and all 4 wires are fine.

 

[Roland Certified Tech]

I'm at a screeching halt on very big wrap project - please help!

I was printing a panel normally when suddenly the printer started advancing super fast WHILE it was printing and cleaning at the same time causing weird diagonal prints. It doesn't stop advancing until I turn off the main power. Once powered on, it sets up as usual, I advance manually past the diagonal misprints, choose sheet cut, then it advances backwards super fast and shoots out the vinyl out the back! Again I have to turn off main power to get it to stop. What the #!* is going on???

Can anyone help?

Thanks,

Yukon

Feed motor or Servo Board.

 

[garyroy]

I'm going out on a limb here. Does it make more sense to put 5K down on a new Roland TruVis VG3 and then have a $200/month payment? You'll double your quality of print, triple your speed and have a warranty along with newer inks and technology. Just an idea. Think twice about putting a thousand $$ into repairs plus your time (that's worth $$) and then have a 15-year-old printer worth about $2500 to $3000. Just sayin'. I had 3 VersaCamm's and loved them. I know how you feel.

 

[damonCA21]

Ok, I'll order a feed motor from Digiprint tomorrow, I think they are about $400, maybe if that doesn't fix I can send it back. Thanks. After that I assume the feed motor board? I just took off the cable for the encoder sensor to the feed motor board and checked continuity and all 4 wires are fine.

If the motor doesn't fix it then it is most likely the motor board or servo board. Often with problems like this it is a case of replacing the various items along the signal path until you find the one that is the issue and ruling them out one by one. This is the joy of fixing printers!

 

[Ewan yu]

On the Grit encoder test, does anyone know what it supposed to show on the screen? The F value keeps going up that makes sense, should the G value also, then both go back to 0? The service manual doesn't tell you anything.

Both F and G should change, and neither of them will automatically return to 0. Not returning to 0 is normal behavior.
When the media is feeding, F changes and G also changes.
When the media stops, both values remain stable and do not fluctuate

 

[HCG]

I would think the M-ENC means the feed motor encoder and it changes the same amount each time then goes back to 0. G-ENC doesn't change but I think it would also. Probably the problem but what is the fix?

 

[HCG]

When doing the servo lock test the motor encoder changes when turning the grit roller BUT the grit encoder number stays at 0, it seems like all the tests show the feed motor working correctly but not getting any reading from the grit encoder and/or sensor. Same results with new disk and sensor. No matter what test the grit encoder number does not change, should this mean a new feed motor board is needed not motor? Doing the Feed motor aging test the motor keeps running forward only in 5 second intervals, never backwards. All these things should mean something.

 

[HCG]

This may be a stupid question, but the grit encoder disk sensor red light is pretty dim - new one and old one. Since it usually is boxed up in the machine in the dark would it have trouble reading the disk in the light? I've turned the lights off also when testing and no difference, also checked the continuity of the wires from the sensor to the board and all 4 good.

 

[Jim Hancock]

This would seem to indicate the feed motor is sending a signal, but the grit encoder is not. As the grit encoder parts are new, this does indicate the problem lies elsewhere. Question - is the grit encoder sensor any brighter with the new sensor? If it is still dim, comparatively, then I suspect it's your servo board. I've attached the schematic of the feed motor board, and it shows the signals from both the feed motor encoder and the grit encoder pass straight through the board and do not go through any circuitry before going to the servo board. Any consensus on this theory?

 

[Jim Hancock]

Funny, I just sent the question right before you posted the answer on the encoder sensor intensity. Here's the schematic...

 

[Jim Hancock]

You might try re-seating the cables that go from the feed motor board to the servo board.

 

[HCG]

CN412 Ribbon cable I assume. Looks in there but I will try. There are still traces that go from the grit sensor CN413 thru the board to the ribbon cable connection. That is why I thought the board may have gone out somehow. In 20 years I've never had this side of the machine apart and it was very clean still. If it's the servo board the machine will have to be parted out, not worth it.

 

[HCG]

Pulled the ribbon cable from the feed motor board to the servo board, put it back and still no go.

 

[HCG]

Looked at the servo board also and reseated the same ribbon cable, no difference.

 

[HCG]

I'm going out on a limb here. Does it make more sense to put 5K down on a new Roland TruVis VG3 and then have a $200/month payment? You'll double your quality of print, triple your speed and have a warranty along with newer inks and technology. Just an idea. Think twice about putting a thousand $$ into repairs plus your time (that's worth $$) and then have a 15-year-old printer worth about $2500 to $3000. Just sayin'. I had 3 VersaCamm's and loved them. I know how you feel.

Totally understand your thought process on this. I'm retiring after 35 years of this and equipment is not worth anything for resale, and would still like a working printer for personal use (we have pictures all over the house and other peoples houses). Still have 2 vinyl cutters, seal 600c laminator, seal EP42 thermal laminator, CNC machine... All things I still use that don't have enough resale value to sell. If I could pick up a used Roland 54" machine for 3k-4k that didn't need new print heads I would and sell my RS-640 for parts.

 

[Ewan yu]

Looked at the servo board also and reseated the same ribbon cable, no difference

If G-ENC is always 0 in all tests, even after replacing the encoder disk and sensor and confirming the wiring is good, then it’s about 90% likely not the feed motor or the sensor. It usually points to a problem on the Feed Motor Board or Servo Board where the G-ENC signal is read.

If G-ENC never changes, it means the grit encoder signal is simply not being seen by the system.

The encoder uses an IR LED, which is naturally very dim to the eye. Ambient light doesn’t matter.dark or bright makes no difference.

Broken wires or bad connectors have already been ruled out, which pushes the problem back to the board.

On a normal VP-540, the feed motor aging test should run forward, stop, reverse, and repeat.

If it only runs forward every 5 seconds and never reverses, the controller knows it’s missing a key feedback signal and falls back to basic one-direction drive instead of closed-loop control.

That points to a failed G-ENC input circuit on the Feed Motor Board (optocoupler / counter / input stage).

The practical fix is replacing the Feed Motor Board.

 

[Jim Hancock]

I agree with Ewan's comments except for the feed motor board being the issue. If you look at the schematic attached to post 33, you will see there is no circuitry associated with the feed motor or grit encoder, only pass through traces, meaning as far as any of the feed motor circuitry is concerned, the feed motor board is a bunch of wires.