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Gefen extend it VGA to ADC conversion box

Green78II

Green78II

6502
I received this with a recent conquest of an Apple 15" Display. It also came with an Apple 205W Power Adapter P/N M5849. They appear physically compatible with each other, but the power adapter seems a bit over the top for such a small device (its over twice as big and easily 6 times the weight of the converter!!). The only things Ive found out about it are that the P/S was used with the G4 Cube, and that the output seems to be at the maximum the VGA converter can handle. I found the specs on the manufacturers website http://www.gefen.com/kvm/dproduct.jsp?prod_id=1301

ADC Bandwidth: 165 MHz

VGA Bandwidth: 350 MHz

Input Video Signal: 1.2 Volts p-p

Input DDC Signal: 5 Volts p-p (TTL)

ADC Connector: 35 pin female

VGA Connector: HD-15 Male

Power Consumption: 208 Watts (max.)

Power Supply: 24-28VDC 60W

Dimensions: 2.75"W x 1"H x 4.5"D

Any insight? Thanks!!!

 
I would think the system was used on a cube as they probably upgraded the video card and lost an adc port. Probably need to find a new power supply for the converter.

 
I think there was also a Dr Bott (or some such) converter box that also used the Cube power supply. I discovered this when my Cube ps died and I thought I'd need to buy a replacement (subsequently managed to fix it).

I have asked the same question, as it is odd that a ps capable of running a whole computer and screen had to be used. I have idly wondered if they were manufactured in large numbers and became cheap because surplus to requirement after the Cube tanked. But that is hard to fathom. Presumably the answer is that there is something in the screen or the graphics slot that communicates with the ps, and so part of the whole ADC specification, so that this particular ps was cheaper to use than setting about to engineer a new one.

 
ADC monitors take their power from the host computer, hence the oversized power supply for using it on a non-ADC machine.

 
^^ and the spec calls for a 60W supply as well. That's why I think this is a bit overkill.

I found some 24v power supplies with a quick search but the smallest I saw was still double that at 120W. The wattage wouldn't overpower anything right? its over-volting the circuitry that does the damage I thought but I was hoping to get that verified.

 
Did you bother reading the complete tech specs on Gefen's site?:

Specifications:
ADC Bandwidth: 165 MHz

VGA Bandwidth: 350 MHz

Input Video Signal: 1.2 Volts p-p

Input DDC Signal: 5 Volts p-p (TTL)

ADC Connector: 35 pin female

VGA Connector: HD-15 Male

Power Consumption: 208 Watts (max.)

Power Supply: 24-28VDC 60W

Dimensions: 2.75"W x 1"H x 4.5"D

Shipping Weight: 5 lbs.
Click to expand...

Note the line that says "Power Consumption". Why that disagrees with the "Power Supply" line I have no idea, but... that is what it is.

Note that there's absolutely no harm in using a power supply of greater wattage than your device needs (outside some edge-case exceptions), it's not going to "overpower" it. The problem comes when using a device that draws more than the supply is rated for. In that case it overheats it.

(As for the "edge case", in case you're curious: Some older "switching" power supplies won't work properly unless some minimum wattage is being pulled from them. This is hardly ever a problem now, but back in the old days if you wanted to, say, use an old IBM PC power supply on your test bench it might not work unless you tie a few resistors across the 5v and 12v feeds.)

 
^^That's what was confusing. I was hoping someone else would be able to make more sense of the power requirements then I could.

 
Ok, so I've tried this thing out, and It doesn't work. I've tried hooking it up to two different iBook G4s and also a PC and the display will not power on. I played around with the different refresh rates and still nothing. Both iBooks are running Tiger, and the PC is running XP. Is there something I'm missing here? The led on the converter box lights up so I know its getting power and the power indicator on the display will flash on and off when I select a refresh rate of 75 hz but it won't actually show an image.

 
This is a 15" ADC Studio Display? Is it known to be working? All these displays had horrible reliability problems, one of the symptoms being the dreaded blinking light.

 
Yeah. It was advertised as working, but the seller took forever to ship it and when it finally arrived I was really busy so I hadn't had time to mess around with it. I have no ADC systems to test it on so I can't be sure what the issue is. What went bad on them?

 
There was no pattern, it was an orange light going on/off/on/off etc in an infinite loop with no short or long blinks.

 
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