I wanted to give this a bit more visibility as it might be of interest for anyone looking to drive Led arrays, so heres a short description for solving the problem with a modified KLD 2150 as an example.
Out of the factory my KLD 2150 suffered multiple problems concerning the power train, especially the LED array was wired incorrectly and way underpowered, the uv leds needed new thermal paste.
LEDs need to be wired in series and driven by a constant current, wiring them parallel is only an option for larger arrays where its impossible to get the voltage levels required for a complete series wiring, multiple parallel rows in series are an option there.
Wiring Leds in series has one main reason: due to the nature of Leds when wired in parallel they exibit different output levels, something we definitely want to avoid in a UV Lcd printer.
Based on this knowledge i searched for a suitable stepup / cc driver and found this monster on amazon: https://www.amazon.de/gp/product/B01C2JB0TQ/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1and
It should be widely available as it seems to be one of these standard Chinese psus which are distributed worldwide.
Beside the obvious size drawback ( Check dimensions ) it can provide power for most uv led arrays you can possibly think of.
after getting it i started to work on rewiring and resoldering the printer to prepare it for the tinxi:
– Ripped out all cabling from the manufacturer, i suspect the main power switch to be the bottleneck here but i just redid everything to be sure there are no other cabling problems rearing their heads later on.
– Resoldered the uv led array to run in series.
– Put in a 33A 12v psu opposed to the 6A unit that came with the printer.
– Superglued a heatsink to the ramps mosfet to keep it cool.
After that was done the interesting part started, dialing in the tinxi to provide the exact amount of power needed by the Leds:
– When you want to use a constant current driver for leds you start of by setting it to the total voltage your leds add up to and add about 10 to 15%, this gave me about 22V ( 3,2V * 6 * 1,10 )
– The next step is to dial the i-pot all the way counter clockwise to set amps as low as possible.
– now you can power up the tinxi, set a typical multimeter to the 10A mode and wire the multimeter in series between the out side of the tinxi and the uv led array, afterwards you can start to turn up the i-pot until it rises to the desired level ( 3A in my case )
– reconnect everything and you are done.