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ROLAND VP-540 Will not power up

Adam Edge

New Member
Hi All,

VP-540 not poweing up. checked board fuses are ok. Replaced main board and powers up so problem is with main board. Does anyone know what to check on board? I have the working board so I can compare componant values. Can someone point me in the right direction please. Thank you!

P.S also checked and working battery and 8 head transistors
 
Last edited:

damonCA21

New Member
The fuses and head transistors on the mainboard don't have anything to do with the power. You need to trace the power from the input through the board, test voltages to the chips, check caps, transistors, regulators, look for shorts etc.. To be honest it's not something easy to do if you don't understand circuits.
You can spend hours checking it and not find the fault, you are better off getting someone used to repairing and diagnosing boards to do it for you. It could also be a failed main chip, which isn't repairable as you can't get replacements.
Having a working board can be useful, but you need both boards powered on at the same time to test them against each other
I do do board repairs for the VP, but am in the UK so you would need to send it over here for me to be able to diagnose it for you .
 

damonCA21

New Member
Hi All,

VP-540 not poweing up. checked board fuses are ok. Replaced main board and powers up so problem is with main board. Does anyone know what to check on board? I have the working board so I can compare componant values. Can someone point me in the right direction please. Thank you!

P.S also checked and working battery and 8 head transistors
Hi Adam, just replied to your ebay message as well, feel free to message me on here :)
 

Adam Edge

New Member
haha, thanks mate just saw!
I see what you mean. found this guide, might give it a go:

 

damonCA21

New Member
haha, thanks mate just saw!
I see what you mean. found this guide, might give it a go:

No problem, the caps are something always worth checking anyway. It is unusual for them to fail on a VP board though, I see this only occasionally, but worth giving a go. If you do decide to change them, be very careful desoldering them as it can lift the pads !
 

Adam Edge

New Member
No problem, the caps are something always worth checking anyway. It is unusual for them to fail on a VP board though, I see this only occasionally, but worth giving a go. If you do decide to change them, be very careful desoldering them as it can lift the pads !
have you ever fixed no power issue? what did you have to replace?
 
Well, VP was a great printer, except the Main Board, usually due to Ethernet connectivity issues.
it is hard to justify fixing a VP if no5 working, although most will agree the fastest CMYK Roland ever made, 4 heads, 4 colors, wow, and fast!
How much time and investment to put into it?
Most I have are working after Main Board replacement for Ethernet Issues.
i could not get one working at all, due to parts availability, Main Board most likely, tried new panel board, etc.
So, maybe get modern…..
 

damonCA21

New Member
It very much depends on the issue. If it's a power issue on the board, and you can get it repaired for £100 then it is well worth not scrapping the printer for that amount ( I had repaired quite a few mainboards with power issues over the years ). I agree the network problems can't be fixed by most repair companies - well they can be repaired, but it's not a component problem, so most places won't know this and will just replace the chip and hope.
 

Adam Edge

New Member
Well, VP was a great printer, except the Main Board, usually due to Ethernet connectivity issues.
it is hard to justify fixing a VP if no5 working, although most will agree the fastest CMYK Roland ever made, 4 heads, 4 colors, wow, and fast!
How much time and investment to put into it?
Most I have are working after Main Board replacement for Ethernet Issues.
i could not get one working at all, due to parts availability, Main Board most likely, tried new panel board, etc.
So, maybe get modern…..
I have 3 of them thats how much i like these printers. I'm not giving up on the VP just yet haha. 1 of them has eth issue, 1 with no power issue, between the 3 I should have 2 working as I have plenty of parts.
 

Adam Edge

New Member
It very much depends on the issue. If it's a power issue on the board, and you can get it repaired for £100 then it is well worth not scrapping the printer for that amount ( I had repaired quite a few mainboards with power issues over the years ). I agree the network problems can't be fixed by most repair companies - well they can be repaired, but it's not a component problem, so most places won't know this and will just replace the chip and hope.
A Youtuber that has fixed no ethernet issue by replacing the crystals suggested to replace the bridge rectifier diode. Where is this located?
 

damonCA21

New Member
You would need to test the crystals first to see if they were working before replacing them.It may have worked on that VP, but isnt the problem most of them have, it is actually with the way the board was designed
 

The Duke

New Member
A Youtuber that has fixed no ethernet issue by replacing the crystals suggested to replace the bridge rectifier diode. Where is this located?
I had the crystals replaced. didnt fix the problem. I just keep a heater on the board to keep the machine printing. Its the only way it wont disconnect.
 

Adam Edge

New Member
I had the crystals replaced. didnt fix the problem. I just keep a heater on the board to keep the machine printing. Its the only way it wont disconnect.
This has to be world biggest mystery. Can human kind not figure out which electrical component on a main board fails when temps below room temperature of 20-22c. haha
 

damonCA21

New Member
It isnt a component. The problem is with the design of the board and the connections. With age and the board flexing through heat and cooling it causes cracks in the connections. Heating these makes the tracks expand and make a connection again, but they disconnect when it cools again and the tracks shrink. This is why they are so hard to repair as it would mean replacing all the bad traces with wires instead
 

Adam Edge

New Member
here is what AI says:

The behavior you’re describing could indicate a failing capacitor or a component that has temperature-sensitive characteristics, such as certain types of semiconductors.
Electrolytic capacitors can exhibit issues at lower temperatures, such as increased ESR (equivalent series resistance), which can lead to failure in circuits that rely on them for stability.
Additionally, thermal expansion/contraction can also affect solder joints and connections on the board, leading to intermittent failures.
If the board functions at warmer temperatures but fails below 20°C, it may be worthwhile to check for:
  • Capacitor leakage or degradation
  • Cold solder joints
  • Thermal-sensitive resistors or components
Testing the board at varying temperatures and checking the specific components involved would help narrow down the exact cause.
4o mini

You said:​

which semiconductors

ChatGPT said:​


Several types of semiconductors can exhibit temperature-sensitive behavior, leading to failures at lower temperatures. Here are a few common ones:
  1. Bipolar Junction Transistors (BJTs): These can become less reliable at low temperatures, leading to decreased current gain and potentially causing the circuit to malfunction.
  2. Field-Effect Transistors (FETs): Some FETs, particularly MOSFETs, may have performance issues at low temperatures, affecting their switching characteristics.
  3. Diodes: Silicon-based diodes may have increased forward voltage drop and reduced reverse recovery characteristics in colder environments.
  4. Operational Amplifiers: Certain op-amps can have offset voltage and drift that worsen in colder temperatures, leading to inaccuracies in circuits.
  5. Integrated Circuits (ICs): Digital logic ICs, especially those designed for standard temperature ranges (like commercial-grade), can experience issues such as timing errors or increased leakage currents.
If you suspect a semiconductor component is at fault, you might want to conduct thermal cycling tests or use a thermal camera to observe temperature-related behavior in real time.
 

damonCA21

New Member
That is why there is no point asking AI compared to someone who has actually worked on the specific board in question :D
 
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