Anyway to filter out bad signals from a regualr vid card on a 15hz monitor?

[tyson171]

Hey everyone, i want to filter out the intial bad signals coming from my computer during bootup?  Right now i have an older 25" wellsgardner 15hz monitor running off of a windows machine and a regular video card using soft15hz to run hyperspin.  I was looking to an alternative to the jpac and the arcadevga card.  Is there anything that just filters out the bad video signal? I want to simply just hit a button and have my arcade boot up and not have to worry about about messing my monitor up?  Just don't want to spend 40 dollars on a jpac just to filter out a bad signal (or however much it cost...)  I've got an extra optipac....anyone want to trade for a jpac? lol. I also have a bad arcadevga card, has a short on the board and the ultimarc guy never responded .

[MonMotha]

I've got a little doohickey I've been building that does just that (optional video amp, too).  It's not available yet, but I could possibly build one for you if you want.  I don't know yet what it will cost, but it should be under $30 and includes a hook-up cable.

[SirPeale]

When I first started in this hobby I was worried that I was damaging my monitor by feeding it the wrong signal.

Now that I've built a handful of them, I can say this: it's not doing anything other than displaying a crappy picture for a few seconds until the drivers kick in.

Unless the monitor is /really/ squealing, that's a good indicator that it's being fed a signal that's not good for it, you should be okay. 

[Ummon]

That's how it is with the 29" CGA monitor in my candy, but I thought all the old/older monitors were susceptible to harm. It's all over the place online. ??  Anyways, Tyson, check out my Candy video for real-time instruction on avoiding bios screens.

[SirPeale]

That's what I was told too, Ummon, but I've got real oldies in my cabs: K4600s, and so far it's been six years without incident.

[MonMotha]

Most digital monitors will shut down when presented with out of range signals.  That's perfectly safe, assuming they do it reliably.

Most analog monitors will lock their PLL on every other line, giving you the "double screen" effect.  This is safe.

Some analog monitors, especially ones that are switchable 15k/25k will manage to lock on each line of VGA or (more likely) every other line of SVGA (800x600, default mode Windows runs in).  This could cause damage.  It also usually results in a really bad noise, so you'll know to power it down quickly

[Beretta]

any thing more going on with this?

im planing on using a vga card with 15khz as well and have the same situation..

from my reading there are are a few ways around this.

1. put in a 2nd video card ex: you have pci-e or agp primary card put in a secondary pci and set the bios to have the pci as default.. then disable the pci card in windows..

basically this will have make the computer output to the pci card till it gets to windows.. at which point windows, 15khz and the primary card will take over and output safe freqz.

not the most eloquent solution and does not eliminate the posibility of a freak accident and having higher freqz on the primary card..

2. only switch on the monitor after you're in windows

3. hook up a relay to turn the monitor on once windows is loaded.. similar to #2 but automatic.

4. get a J-pac.


i like you would like to beable to buy or have plans to build a simple filter, just as a safety net..

im curently leaning towards the relay coupled with a program to disable/enable the relay only when the freqz is within safe levels, im not much of a programmer though im hopping i try and accomplish this with autoit scripting, checking refresh freq say every 100-200 ms and switching the relay on/off accordingly.

i think someone making a freqz filter could definitely find a market if it's reasonably priced.

[SirPeale]

Read this: http://forum.arcadecontrols.com/index.php?topic=93223.msg979910#msg979910