PS1 Graphical Anomalies

Hey,

I'd really appreciate it if you guys could help me out with an issue I'm having...

I recently bought an NTSC PS1 console from eBay (SCPH-5501). After switching the American power supply out for a 240v European one, I briefly tested it and all seemed OK with the one game I tested it with.
A few weeks later, I wanted to thoroughly test it before I installed a Mayumi V4 modchip and a PSIO switchboard chip (the console is still stock, no mods). As I tested it more, games would occasionally boot up with weird graphical bugs, starting on their initial splash screens and through menu screens etc (I mainly tested Iron & Blood: Warriors of Ravenloft as I only have about 3 NTSC games on disc).
I can only describe it as being scrambled looking, various parts of the screen looked distorted and stretched, colors were mashed up etc... Evidently this game showed the exact same visual issue every time the bug occurred. Coinciding with this, the PS1 boot screen showed an occasional random bug that looked sort of like this: (however the graphical bug here would be different each time)



I decided to try replacing the laser, which I swapped out for a PSone laser which I knew worked (with a ribbon cable extension I bought off eBay, that arrived today). All seemed OK the first few boots but then I saw the bug once again, so I know it's most likely not the laser. It's very random and only happened a handful of times. I just tried rebooting about 20 times and couldn't get it to show the bug for my camera. . Is there a chance this infrequent random glitch is normal? Could a slightly scratched disk cause this to happen?

Do you think this this a sign that the PS mainboard is bad or going bad? I don't want to install the 2 chips on the board only to have to replace it down the line.....any advice would be greatly appreciated!

 

Something like that would not come from a disc as that boot stuff is contained in the bios.

So either your PSU swap is supplying too much voltage and breaking the MB or your other mods are causing it.

 

I haven't actually done any mods to the board as of yet, it's still all completely stock. I did a bit of research before I swapped the PSU and the general consensus seemed to be that they're fully interchangeable, as they output the same voltages to the board.

Also, I thought the black "licensed by" screen is read directly from the CD? Because when you use different region games on modded PS1's, the screen changes from Europe/America depending on what region disk you have in.

P.S. the PSU came from a genuine PAL SCPH-5552 console, and the laser is from a PSone...

 

Laser and PSU are likely fine.
Try touching the various chips on the board while running a 3D game and see if that provokes more of the glitch.

 

Ok cool will do (I'll try not to zap myself off the power supply in the process lol). A lot of the chips are under a soldered in RF shield, do I need to remove that?

 

Yea, the shield will have to go for the test. But it should be worth it: The error definitely looks like IC or trace damage.

 

Ok, will unsolder it now and report back to you. It's strange, the console/mainboard are in immaculate condition.

 

Unfortunately I don't have thick enough solder wick to properly remove the heat shield, rather than make a botched attempt at removing it I will probably just wait until I get thicker stuff. I tried touching all of the visible chips, didn't make the glitch occur anyway. Strangely enough, for the last 30/40 odd boots the system has been problem free. As silly as it sounds I did thoroughly clean the disc earlier and the error hasn't happened since....hardly the reason?

 

What it looks like to me:
One of the chips is damaged and it's not too bad yet. It mostly works.
Or, a solder joint has become brittle and developed high resistance.
There's also a chance your EU PSU is bad. Check the voltages going into the mainboard.


An error reading the disc would rarely produce these kinds of graphic glitches.

 

OK, thanks a lot for the info I really appreciate it. I just tested the PSU pinout (it wasn't connected to the mainboard while I tested, is that OK?). Results were:

1. 7.49v
2. GND
3. 3.54v
4. GND
5. 1.2v - 1.7v while reset button not pressed, no voltage when reset button is pressed.


I had a good look over the board (obviously can't see under the RF shield until I remove it). I can't see any visible bad parts, leaking caps, cold joints, broken legs etc.

 

Hm, the voltages are fine under load. I don't remember how much the 500x series PSU drops voltages under load.
If you could test again with the PSU installed and the console reading a game, that'd clear it up.
Generally, you don't want to see those 3.5V to drop below ~3.45V and the 8V not below ~6.8V.
Reset is probably fine. If the console can reset, it is fine

Edit: Watch out for high voltage when / if trying to reset the console. The reset button is close to the transformer. Best if you do this only when it's back together in the case.

 

Ok, so tested voltages while game was running. The results were:

1. 7.58v
2. GND
3. 3.50v
4. GND
5. 3.43v while reset button not pressed, fairly certain it drops to 0v when its pressed, was quite hard to measure and not electrocute myself at the same time lol (the console resets anyway).

I'm starting to think Im going crazy and trying to diagnose something that isn't there anymore haha, the graphical issue hasn't come back since this morning...

 

You could get glitches that happen when the console is "cold" and go away after it's warmed up. That could be the result of a bad connection somewhere maybe. If the problem isn't happening at all for now, then maybe you shouldn't worry about it until it comes back. But if you are planning to mod it like by installing PS-IO then you might actually want to solve it or use a known good system instead of modding a flakey system.

 

Yeah that's a valid point. The glitch only happened about twice within the first 5 or 6 boots yesterday morning, then they never came back. It could well be a hot/cold thing going on. Yeah it's a tough one alright, on one hand I want to just install the 2 chips and play it until the issue comes back, but then on the other hand if I can fix it, now is definitely the time to do it.

 

The PSU at least is fine
Maybe install the mods now and look for another 5001 for when this system goes bad again.
It'll be quite simple to transfer the mods over. At least simpler than diagnosing and fixing the issue.

 

Yeah I think you are right rama, I'll probably just install the mods and hope for the best. I can always transfer the chips to a new board if it comes to that. Thanks for the help

 

If the console is giving you so many issues I'd recommend getting another working PS1 and doing all the mods on that, PS1 consoles only are cheap now and can be found for tops $30 USD.

 

Yeah that's also an option....It's just a shame to have just bought this one and not use it. As rama said it should be straight forward enough to unsolder the wires for the modchips and switch em over to a new mainboard if it comes to that. I'm also going to recap the power supply as someone gave me a heads up that although the voltage could be fine, the capacitors can fail over time and output "dirty" voltage...

 

Yea, PSX capacitors are of the SMD type that tends to fail sooner.
When I inspect a PSX, oftentimes there's a few out of spec capacitors on it. I find them mostly on the 8V and 3.3V input filtering rail and on the Composite / S-Video output end (those 4V 220uF). Oh, and the 100uF 5V rail reservoir capacitor for the video encoder! This one is critical for image quality and it's almost always out of spec.

It's possible that bad caps produce this error but a little unlikely. Doesn't hurt to replace bad ones though.

 

Just an update, I've since installed a Mayumi V4 modchip and the PSIO switchboard. No sign of the bug and the genuine sony KSM-440BAM laser with the ribbon cable extension is playing both NTSC and PAL game disks perfectly. Still waiting on more capacitors to arrive for the PSU but so far so good....Long may this last.....I hope :/