Roland Sp-300 Not Turning On

[SheddShirts33]

I have been searching this site for years and always get answers to problems I am having and finally making a post after about 13 years and hopefully someone can help me.

My SP-300 would not turn on the other day when I got to the shop. Had the Roland tech come and said it was getting power when I hit the power switch and needed a new power board(I think thats what he called it)

I got a new one installed it and still cannot get it to turn on.

When I switch the on//off button I hear almost like a faint zapping noise but then that is all and it wont turn on. If I switch the on off button again, nothing happens unless I unplug it and try and turn it on again and will hear the faint zapping noise once again.

Really hoping someone has some suggestions because this machine has been old reliable and great as an extra unit for when it gets a little busier.

Thanks in advance for any help!

 

[damonCA21]

Did he change the power supply? That is weird if the printer was getting power into the main boards. It sounds like it could be the control panel has failed rather than the power supply. I have replacement control panel boards in stock if you need one.
If you are getting a green light on the main board and print carriage board ( the one above the print heads ) then it's not a power supply issue, something is not switching the actual main board on

 

[SheddShirts33]

I have attached a photo of where the power stops. I really am not sure and have no ideas and any help is appreciated. The red arrow is where the power stops.

Thank you!

 

[damonCA21]

When you turn the printer on are you getting a green light on the main board? If not then power is not making it to the board to boot it up

 

[damonCA21]

Have you measured the plug on the power supply to see if you are getting a 5V voltage from it?

 

[SheddShirts33]

No lights are turning on. I will see what voltage I am getting from the power supply right now and report back. Thank you again!

 

[damonCA21]

No lights are turning on. I will see what voltage I am getting from the power supply right now and report back. Thank you again!

It is possible the new power supply he has fitted is faulty, but he should have checked this when he fitted it. I have working tested OEM power supplies in stock if you need one

 

[damonCA21]

Note if the new supply is one of the cheap ones from china, then it quite possibly is faulty

 

[netsol]

the "faint zapping noise" you describe is probably the 12v or 5v supply trying to start, loaded down by a short.
when you power on, the main board is not generating a "power good signal

 

[SheddShirts33]

I just bought this volt reader so I really am even sure if I am using it correctly but In the attached picture the part I am touching is showing 7 Volts but the other part of it seems to not be getting any volts that I have circled if that makes sense. I have tried a cord from a different roland printer and getting same results.

 

[damonCA21]

You are reading the voltage in the wrong place. You need to test for DC volts on the output plug on the right hand side of the power supply and see if there is anything there.

For the mains input you need to test for voltage between the live wire and ground. You need the black probe on the green/yellow wire and the red probe on the brown wire.

 

[SheddShirts33]

When I Put the black probe on the green yello wire and the red probe on the brown wire, I got a reading of 0 if i was doing it correctly. When I use the Non Contact AC Voltage detector in that area, I am getting a beeping like there is power there. Again I have never used these before but putting the probes on the wires you explained, I got no reading

 

[damonCA21]

Are you getting a DC voltage output from the power supply?
If you are definitely not getting any AC voltage coming into the printer then it is either the lead or the input socket for the mains

 

[netsol]

green/yellow is "hot ground" for ac line voltage
without looking at the machine, your "cold ground" (the one you won't get a shock when you touch it) might be a black wire, as well as the exterior metal surfaces of the machine [the ones that cabinet screws go into]

damonca21 mentioned a green led on the system board. if you don't see that then power is not being supplied from the power board

what was the source of your replacement power board? was it from china? used board from ebay?
does it act exactly the same way as the original board when you install and apply power?

 

[SheddShirts33]

How would I test for that?

 

[SheddShirts33]

The circled item is what I replaced and it was a used one from ebay. Seems to act the same as the previous one

 

[netsol]

the reason i asked, (having done a lot of this, over the years) is that getting a bad used part is not that unusual
getting a used part with the same type of defect (or yielding the same result) is more unusual

you could be plugging a good power supply into a bad system board

IN A VERY QUIET ROOM apply AC (from power plug) to the power supply with the system board unplugged.
do you hear anything?

 

[SheddShirts33]

So unplug the power board, plug in the printer and then hit the on switch and hear if I hear the same faint buzz noise?

 

[netsol]

yes. i am doing this as we go. making a few assumptions.

 

[netsol]

i sent you a message
2 friends in the business close enough to be practical if you need to send or exchange a board
just thinking ahead...