View Full Version : Why always me??? (Kvant)

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03-27-2015, 07:45
The scenario:

I have a Kvant Spectrum 1.6 watt projector purchased from someone in Europe about 4 years ago. It came with the European plug and the powercon receptacle on the case is marked 230v 50Hz. I first tried when I got it to just change the plug to a US Edison style plug and give it 110v as the thinking was it probably had switching power supplies. 110v provided "some" power but not enough to run it properly. I purchased an aftermarket step up transformer that boosts 110v to 220v and have used that successfully a number of times. The hypothesis was the power supplies inside the projector must only be set up to accept 220v.

It's a bitch to take apart and I have started a couple of times and then stopped since it's worse than working on a foreign car engine with everything being so tight and naturally the power supply labels faced down towards the baseplate. So, I finally have ripped this thing down and have screws littered all over the place but have now inspected each of the three power supplies. There is a Traco 12v. An unsure brand 24v and an unsure brand 6v. They're all turning out to be switching from 90v to 240v as far as an input. So.... WTF???

Upon closer inspection, it appears that the main power in goes to a card I've not seen before which is a Kvant Measuring and Information Monitor card. Coming off the card are: a mains power lead to the Traco 12v supply (which is jumped to the other two supplies. A ribbon cable going to the LED screen on the back of the projector which reports temperatures. A lead to a temperature sensor stuck on top of the green module, And two sets of black and white power leads that look like they run to cards underneath the Measuring and Information Monitor and are likely the driver cards for a Kvant combined red/blue module.

Here's some pics:


Besides just mailing this to Swami, as he'll undoubtedly suggest, any thoughts? Could it be the Kvant card is what requires 220v and if it's not getting it, it doesn't allow power to the rest of the system? I hate using the step up transformer as a) it's one more thing to lug around and b) we've discovered, particularly in the auditorium in Newton, that the output of the projector definitely goes wonky and jitters with that lovely theater electric.

03-27-2015, 07:48
send it to swami.

03-27-2015, 08:00
I knew I could count on you to be helpful! :)

03-27-2015, 08:10
I knew I could count on you to be helpful! :)

it's my way!


03-27-2015, 08:19
On the cable that you have marked as "out to power supplies", I'd measure the AC voltage you have there. I bet it's as simple as rewiring to that screw terminal but I wouldn't make a change until I know what the voltage is on all the terminals and understand what's going on.

Better yet, send to swami!

03-27-2015, 08:28
I've no idea what that big black lump is on the board, but it clearly says 230V on the side of it.

03-27-2015, 08:32
What Norty said. Looks like a 6V PSU of some form. Maybe you could get that swapped out for a 110V version

03-27-2015, 08:37
The big black block on the Kvant board is a power supply that's marked 230V. So no - you can't just wire around the Kvant board and run 120V without some component level redesign.

03-27-2015, 09:29
Crap.... I was afraid of that. :p Maybe it's time to sell it back to someone in Europe. I suppose it may be possible to bypass the health monitor but, I think it controls cooling fan speeds though.

Meanwhile as DZ thinks, "Please, dear God... not another thing for him to bring to me! :)"

03-27-2015, 09:43
... here in Germany I can buy 'line-changers' for different AC voltages, that changes down from 230VAC to 115VAC or the other way round - it's mostly done with a simple 2:1 transformator, or turned to 1:2 ... they only have to be wired for the needed currents - and checked, if the target device is capable of 50 or 60 Hertz.

So maybe you can insert a 115VAC_to_230VAC transformer and appropriate fuses?