Dreamcast reboot/black screen

So I've read on how you're supposed to bend the psu pcb connectors and I've done this, I've cleaned them and I also had the powercord port resoldered by a pro. I've tried several powercords and AV-cords and have concluded that it's not the cords.
The problem is this: whenever the console is turned on the led goes on and the logo intro starts.
7 out of 10 times it will reboot or simply go black without finishing the dreamcast logo intro.
Meantime the powerled is on at all times, it doesn't blink or anything, indicating that it's not the psu.
The disc however stops spinning for the time of the reboot, or completely stops if the console "blackscreens". There's no rule to whether it blackscreens or goes into bootloop, it's pretty much 50/50.
The other three times I'm somehow able to force it to boot by sheer willpower (there's no other feasible explanation).
Maybe you guys know what's going on?

 

Have you tried running it without the RF shielding?

 

The what now?
Edit: google told me what. But why would that matter?

 

Could be the fan? If it does not detect the fan spinning, it will shut down within a few seconds.

 

It could be, I'll try to check this.

 

There is, unfortunately, a whole bunch of stuff that can cause this, and the easiest way to isolate the problem is by swapping parts, which it sounds like you don't have access to.

My first guess would be bad connections on the power supply, but it sounds like you have already ruled that one out. The second would be a bad GD-ROM drive (shorted BTL driver or motor) that's pulling the power rail down when it tries to read the disk - a quick a dirty test for the motor is just seeing if it boots reliably with the drive door open, but resets/crashes with it closed - but this will only catch motor problems, and not a faulty BTL driver.

You can also try removing the GD-ROM drive completely and seeing if it will boot to the BIOS - but you have to be patient if you do this, because the timeouts are very long and it looks like it's just locked up - but after a long time (minutes) it should go to the BIOS screen - if it does this reliably with the drive unplugged but crashes with it plugged in then it strongly suggests that the GD-ROM drive is bad.

I suspect you have a PAL unit, so this doesn't apply - but if it's a Japanese or US unit with a 100/120V PSU then it's worth checking the filter cap on the PSU for signs of overheating - even short connections to 220V can cook the cap and result in poor regulation.

Other (IMO, less likely stuff):

Bad control PCB / Fan / Ribbon cable is messing up the tachometer signal (this normally causes black screens, not resets, though).
Missing silicone pads on the SH-4 or the PowerVR (these normally cause overheating related crashes after you have been playing for a while).
Damaged solder joints on the main PCB (possible, but very unlikely - I think I've only seen about 3 bad main boards ever...)

Oh, one other thing that's worth trying is taking the console into a quiet room and slowly rotating the disc hub - if you hear clicks, then you have a bad motor - unfortunately, this often blows up the drive chip on the GD-ROM board, too...

 

That's a lot of good info. Thanks a lot. I do have a pal unit. When I get my hands on the console (it's at my dad's place) I'll crosscheck as much as possible. Thinking of maybe buying a jap/us one and swap the psu (the imports are cheaper here in sweden lol), but that's just a thought. Ideally I'll be able to fix this with some help from the internets, that is awesome guys like you . I really don't like to throw stuff away. Like the other day I found two old pcs from 1999 in my garage and instead of throwing them away I took whatever was working and put it together into one working unit. It dualboots w2k and xp now Don't know what to do with it but I ain't trashing it

 

If you need a new PSU or just want a place to test it near Stockholm (I have a few we can test parts with), let me know...

 

Tjena Where are you? I'm near Västerås ^^
Nice of you to offer, we do have a rather friendly videogame shop here that I visit when I need to test with stuff that I don't have, but you never know

 

the things is, whenever it DOES boot the drive works too and games play fine. I almost want to leave it on forever lol

 

Holy crap. Do I feel dumb or what.
After watching +5 videos on how to bend the psu pins I finally realised that the last time I bent them - I bent them the wrong way.

 

I was going to say that that REALLY sounds like a bad power supply connector. Then I saw your next post. You are not the first person to do that, and almost certainly won't be the last - the main reason being that most of the guides don't bother to mention that depending on who made the PSU in your DC there are two possible orientations for the connector on the power supply board.

 

Well, it works now. Which is awesome.
It plays backups and gdroms fine, but for some reason it always has problems booting a backup of Project Justice. No matter what brand of cdr or if it's burnt at the slowest possible speed.

 

That game's dump could be a bad dump. Is there another dump you can try? Is the game larger than 750MB?

 

I have 3 cdrs of it, all are from the same echelon release.
- new, black, cdr that worked normally the first two times. Now it either
a) loads for a long time and goes to bios or
b) bootloops at the dreamcast logo.
There are no scratches on it.
- an older, silver, cdr just does the long disc check and goes to bios 9/10 times. Both this one and the black one was burned at 4x.
- third, new, silver, offbrand & burned at a whopping 52x works perfectly each time.

Same thing with Deatch Crimson ox. Burned a copy on
- an offbrand cdr at 4x and it goes to BIOS after a long disc check.
- one cdr from the same batch but at burned at 52x and it works perfectly.

Then I burned Elemental Gimmick Gear at 52x and this time the disc goes to bios..
Burned it again at 4x and it boots.
What the fack?! Are there some kind of rules for how to burn certain games?
All of these were CDIs burned with imgburn.