NEw tube and PS not working so good.

Discussions on optics for laser cutter/engravers

Re: NEw tube and PS not working so good.

Postby macona » Sun Jun 05, 2011 5:17 pm

FYI, when it comes to mains power there is generally no such thing as two phase power. 240 will be either single phase or three phase. 120v in a house is derived from a center tapped transformer so the phases are in sync with each other.

Two phase does exist and it was used in the past. I believe there is one place around Niagara falls that still uses two phase 25hz power for industrial use. Two phase has the phases 90 degrees out of has with each other.

You might check inside the power supply. There may be jumpers to change it from 240v to 120. It is very rare for a company to make supplies like this dedicated to 120 or 240v.
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Re: NEw tube and PS not working so good.

Postby BenJackson » Sun Jun 05, 2011 9:56 pm

Since mine is not doing anything I opened it up. I can't vouch for it being 110V without a tube, but it is labelled. I don't see anything that looks switchable. It is possible that those multi-turn trimpots on the vertical potted circuit (which is embossed with http://WWW.JNHYEC.COM on the side) can be tuned for 110 vs 220. Since they are multi-turn you can't go solely by the position of the setscrew.

IMG_0602[1].JPG
A friendly "HELLO", or "AC110"
IMG_0601[1].JPG
Overview of the PCB (there's nothing interesting on the bottom)
IMG_0603[1].JPG
View of input power corner
IMG_0604[1].JPG
Alternate view of input power corner
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Re: NEw tube and PS not working so good.

Postby macona » Mon Jun 06, 2011 12:14 am

The trimpots will have nothing to do with 120c vs 240v input. They are most likely pots to control frequency and duty cycle of the PWM IC that drives the power transistors.

The switching is done on the power input side. It changes the input from a direct input for 240 to a voltage doubler for 120v input. Might be something on the back side of the PCB.
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Re: NEw tube and PS not working so good.

Postby BenJackson » Mon Jun 06, 2011 7:51 am

macona wrote:The trimpots will have nothing to do with 120c vs 240v input. They are most likely pots to control frequency and duty cycle of the PWM IC that drives the power transistors.


Not impossible that they built a controller to tolerate that much variation in the DC input to the inverter. However having looked more closely at the large caps...

The switching is done on the power input side. It changes the input from a direct input for 240 to a voltage doubler for 120v input. Might be something on the back side of the PCB.


The only large rectifier on the board is the full bridge in the lower left of the last picture, obviously followed by those two 680uF 200V (!) electrolytic caps. There's no room for a doubler on the input. Perhaps the 220V version is using a half-bridge instead? Different component(s) there or only using half the rectifier. The only wire I see on the bottom of the board (without removing it) is in that vicinity, but there is a silkscreen for the rectifier labelled "BRG" so the 110 version seems to be the "natural" version. I look forward to pics of the 220V one.
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Re: NEw tube and PS not working so good.

Postby naPS » Mon Jun 06, 2011 7:56 am

Yeah, I'll pull mine apart once I have everything set up and rocking. I'm almost done adjusting the mirrors, and after that, I'm good to go, so I'll open it up after that.

The power connection location and fan are completely different on mine though, even though it has the scratched out 110AC on the outside of it.
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