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What should happen when I plug 631 into USB port?

Z-Knight

New member
I have the 631 model...got it today, and I can't get it to work via USB on 2 different PCs.

I followed the instructions to install the drivers, connect the display and let the drivers get configured, and then I started the WinTest 2.0 tool but sits there and has a status of "Looking for module..."

When I unplug the USB, the CrystalFontz disappears from the Ports listing, when I plug it in then it appears again...so I know there is some recognition going on, but I have no display on my LCD and nothing is happening.

I'm only using the USB connection...nothing else. What am I missing? I tried this on 2 different PCs and nothing...same results on both.
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CF Support

Administrator
Did you purchase the LCD with a SCAB? If so, you'll need to have the 4-pin floppy-drive type power cable plugged into the SCAB, and the SCAB connected to the LCD module.
 

Z-Knight

New member
I guess I'm a little confused here...I thought the SCAB would be optional. Yes I do have one. I unplugged it and right now I don't plan on using it and strictly use the LCD display. Are you telling me I have to use the SCAB, this does not make much sense to me since I think the website says the SCAB is optional.
 

CF Support

Administrator
The SCAB is optional, but when ordered at the same time as the LCD, JP2 on the module is opened so that the USB bus is not back-powered from the LCD when the SCAB is connected.
 

Z-Knight

New member
The SCAB is optional, but when ordered at the same time as the LCD, JP2 on the module is opened so that the USB bus is not back-powered from the LCD when the SCAB is connected.
IC...that's where my disconnect (literal) occurred. I don't have the module in front of me, but is JP2 simply a jumper? and if so, can I just simply short it and hence be able to have the USB provide the power or would I need to purchase a 631 without the SCAB module?
 

CF Support

Administrator
JP2 is a solder jumper of sorts, so putting solder across the two contacts will get you what you're looking for.
 

Z-Knight

New member
Thank you very much..that did it.

One followup/related question...having this JP2 shorted, thereby using USB power, what would happen if I had the SCAB connected and I had it connected to floppy power? Would that be a conflict? I realize, I could just unsolder the JP2 but I'm curious if there would be an issue...I'm guessing yes since there would be no purpose to having that JP2 open. :)
 
USB LCD Displays - Graphic and Character LCDs with a Keypad

Heffo

New member
You would start back-feeding power directly from the PSU into your USB controller, instead of the USB controller supplying power. This could turn out to be a rather bad situation for the controller.
 

Z-Knight

New member
You would start back-feeding power directly from the PSU into your USB controller, instead of the USB controller supplying power. This could turn out to be a rather bad situation for the controller.
Figured as much...thanks. I should have simply traced it back and I would have seen that this is definitely a bad move. Thanks.
 
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