DREAMCAST VGA QUESTIONS! come here for everything VGA w/ DC.

[ArrYouGonnaEatThat]

Does it cooperate hooked up with the plain old composite cable? Do you have another 640 monitor you can try it on? It's possible that a component is failing in the VGA box and the signal goes out of spec once it warms up.

I just tried it on a 10" monitor and it does the same thing, so I think you're right that it's a bad component within the VGA box. I've got new composite and VGA cables coming in the mail tomorrow. The VGA box I have now is one of those clear plastic deals.

Thanks for the quick reply!

[marurun]

You might be able to find someone on here who does mods who might be able to crack open the box and look for problems.

[ArrYouGonnaEatThat]

You might be able to find someone on here who does mods who might be able to crack open the box and look for problems.

I just tried it with brand new cables and it's doing the same thing with a VGA box, VGA cable, and composite cable, which leads me to believe that maybe the problem does have something to do with the fan. I don't understand why that would be, because it's a brand new 5V 30mm 8000 RPM fan. Isn't the Dreamcast supposed to power down automatically if the fan's not being detected properly? It's not powering down, it's just cutting off the video signal. Light's still on, fan's still running.

EDIT: I'm going to browse the rest of the forum and try to find some fan-related topics since I don't think the problem is the VGA box anymore. What I think it might be, is that the new fan draws more power than the original fan did, so maybe instead of plugging into the controller board it should connect to the power board somehow.

[Hobie-wan]

A thought, what is the RPM of the original fan compared to what this new one runs? If it is the fan, maybe it is being confused by the speed it isn't expecting? I'm just guessing.

[ArrYouGonnaEatThat]

A thought, what is the RPM of the original fan compared to what this new one runs? If it is the fan, maybe it is being confused by the speed it isn't expecting? I'm just guessing.

The original fan is an NMB 1204kl-01w-b49 (45V DC 0.20A 0.70W 9000 RPM 23 dB 3.2 CFM)
The new fan is an Evercool EC3010M05CA. RPM is 1,000 less than the original DC fan, moves .5 CFM more air, 1 dB quieter (big whoop) and costs 1/3rd as much.

I managed to find the original DC fan from a Chinese supplier. It was hard tracking down a store willing to sell one of these babies (most want you to buy at least 700-1,000).
http://www.dhgate.com/store/product/nmb ... 28279.html

I'm not sure if I should just cut my losses with the Evercool and get the NMB.

[marurun]

The Evercool pulls .9 watts and operates at .18A. The original, per your information, is .7 watts and .2A. That's really not much difference at all.

[ArrYouGonnaEatThat]

The Evercool pulls .9 watts and operates at .18A. The original, per your information, is .7 watts and .2A. That's really not much difference at all.

That's what I thought, and it's why I got the Evercool. Do you think it's enough of a difference to cause this video signal cutoff problem?

[marurun]

The Evercool pulls .9 watts and operates at .18A. The original, per your information, is .7 watts and .2A. That's really not much difference at all.

That's what I thought, and it's why I got the Evercool. Do you think it's enough of a difference to cause this video signal cutoff problem?

Electronics at that level are a bit beyond my ken, but I'm going to guess probably not. That doesn't mean you didn't possibly induce a short somewhere when you installed it, though...

[ArrYouGonnaEatThat]

The Evercool pulls .9 watts and operates at .18A. The original, per your information, is .7 watts and .2A. That's really not much difference at all.

That's what I thought, and it's why I got the Evercool. Do you think it's enough of a difference to cause this video signal cutoff problem?

Electronics at that level are a bit beyond my ken, but I'm going to guess probably not. That doesn't mean you didn't possibly induce a short somewhere when you installed it, though...

I'm really hoping that's not the case. It's not like I messed with the soldering on the board; I just changed plugs on the new fan and slapped it in there.

Last I checked, the original DC fan I ordered was dispatched from a sorting center in Guangzhou on the 24th. I'm hoping it reaches the US by October 1st, which is when China's national holi-"day" begins (it ends on the 7th, and nobody gets any work done for the whole week). I think I should try it with an original spec DC fan before I try soldering the Evercool to the power supply, because like you said I don't want to induce a short.

[Mad_Hatter]

Has any one tried one of these?

http://www.ebay.com/itm/Sega-Dreamcast- ... 27ed5ada3b

It's a VGA Cable with a built in Scanline generator. sounds like an neat idea.