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Title: MV-1B white screen Post by: k4 on October 24, 2013, 04:56:53 PM Hi everyone.
I bought a pair of broken mvs boards really cheap and i'm trying to fix them. One is fucked up pretty badly, but i can get some use out of it as a parts board. The other one, a mv-1b, is in great shape, no signs of physical damage, and yet boots up to a white screen. I tried resetting the ram, and got some vertical stripes that go away after some time. I'll attach the pic if it's of some help. No chip is getting hot while powered on and after sometime the board resets itself. Thanks for your help. Title: Re: MV-1B white screen Post by: channelmaniac on October 24, 2013, 05:27:23 PM Post pics of the top of the board (with the riser removed) and of what it's doing on the monitor.
Title: Re: MV-1B white screen Post by: k4 on October 24, 2013, 06:40:19 PM Here they are:
https://www.dropbox.com/sc/jxabk23vmyq6vfm/I7Xp09Pb8a (https://www.dropbox.com/sc/jxabk23vmyq6vfm/I7Xp09Pb8a) Title: Re: MV-1B white screen Post by: channelmaniac on October 25, 2013, 01:37:42 PM Hadn't seen a screen like that before.
Do the normal checks first: look for bent pins, corrosion/spill damage, and gouged traces. Push down on the SMT chips while you power it up to see if you have bad solder on them. Beyond that, I'd start by checking the Work RAM and Backup RAM - particularly the enable lines first to see if signals are missing then the address/data lines for the same thing. After that, swap out the backup and work RAM. Title: Re: MV-1B white screen Post by: k4 on October 26, 2013, 09:52:38 AM Can i swap the toshiba ram chips with the sony cxk58257am i have in the other mv-1fzs board i have?
Title: Re: MV-1B white screen Post by: channelmaniac on October 26, 2013, 08:40:42 PM Check the data sheets. Should be the same, but always check the datasheets.
http://www.datasheetarchive.com (http://www.datasheetarchive.com) Title: Re: MV-1B white screen Post by: k4 on November 15, 2013, 05:07:31 PM I actually had a problem with the sync signal in my tv.
Fixed that and now this is the screen i see. Title: Re: MV-1B white screen Post by: channelmaniac on November 20, 2013, 12:17:02 AM OK...
That one is when the CPU isn't booting. Check the /OE, /CE, and R/W signals on the Work and Backup RAM to see if they are there or are stuck... check the address/data lines to those chips and to the BIOS ROM. Also check the /CE signal on the BIOS ROM. Raymond Title: Re: MV-1B white screen Post by: k4 on November 25, 2013, 08:36:37 PM Hi, i tested the bios and ram and everything seems ok, apart from pin 2 of the bios, which i thought should be connected to the ground but really isn't. I tried connecting it but nothing changed. I tried changing the bios with an mv-1fzs one, without luck. But maybe i did it wrong, as i followed the unibios procedure. I decided to remove the bios altogether as i'm waiting for an unibios. I don't have a logic probe right now so i can't test it further until i get that. I ordered one.
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