Velleman won't go past a certain temp

[tom10122]

I can't get my velleman to heat up past a certain point, it cycles on and off at lower temps fine but at higher temps that I need to properly melt the plastic it just keeps tryning to heat up , It's not overheating. At first I thought it wasn't getting enough current being on a generator, but Now I have my power back and it does the same thing. I also thought maybe only one resistor was working but now the connections are soldered and it still won't go past a certain temperature. When I take the hotend off my printer It cycles at that setting fine for some reason, Maybe I should replace my wiring for that? Is CAT5 doubled up enough for it?

[johnoly99]

Yeah, i'd try upping the wire size running to the heating resistors. That sounds like where you're starving it for power?

[adman234]

Hi tom,

My vellman board came with an extra resistor, I think I remember reading somewhere that this extra resistor should be used if you want to go the the higher temps.

I just thought that maybe this was the case?

[tom10122]

John, I was thinking Of replacing the wire with that, I was using 12 gauge wire before which was fine. , It's not the resistor either, it was working fine with this setup before .

[tom10122]

re did the wiring but no luck , it works sometimes when nothing is on except the velleman, now it seems as if the velleman isn't being supplied enough power but this setup worked before, It is a 450 watt psu with 4 yellow and black wires going to it.

[Fiero2M6]

Could the Velleman have a loose solder joint on the pcb board? I doubt the power supply would go bad.

[tom10122]

I really have no clue what's going on now, re wired it with 18gauge wire, reflowed any solder on the board that wasn't perfect and replaced the resistor for t-max, it still only heats up to a certain temp and won't/can't go past that , It keeps trying to but it can't. Help?

[adman234]

try checking the voltage on the PSU, just in case. Mine was only doing about 3 volts.

[tom10122]

No the psu is fine, it powers my computer fine

[Polygonhell]

No the psu is fine, it powers my computer fine

You need to measure the voltage from the PSU when running the vellerman.
Some ATX PSU's have an issue where they cannot maintain good voltage on the 12V line without there being a significant load on the 5V line.
The usually shows up as a big voltage drop (to <10V) when you try and draw significant current from it.

A PSU that does this will "powers my computer fine", but will probably result in not reaching high temperature.

If your PSU is doing this you need to put a load on the 5V line or find PSU that doesn't do that.

[tom10122]

I'll check , If that is the case then how would I go about loading the 5v?

[tom10122]

constant 12v all the time

[markotime]

I found a break in the pc board foil right at one of the pads holding a resistor (ordiode or something). worth checking for 12v other places on the boards/m