PSOne laser louder after mod chip install.

Hi Guys, I have recently modded a PSOne with a ONEChip, and I've noticed that the laser is a little louder now. The chip appears to be working fine as the console will play everything with no issues.

No major problem, it's just bugging me a little!

Anything I should look out for in particular?

Here's a pic of the mod. Not the neatest I know but I'm still learning!




Thanks for any advice!

 

Is louder with all media or just burnt media?

 

Are you able to fit rf shield (big metal piece) properly now?
I remember that it's sunken beneath the laser assembly and the only decent place for 12c508a OneChip I found is to place it on top of the boot rom (aka BIOS).

It could be that the whole assembly is slight higher then usual and the spindle is hitting top of the lid or shielding rattles now when disc is spinning.

 

Hi Guys thanks for your replies, the RF shielding fits just as it should, the chip sat where it is hasn't obstructed it in any way.

The noise is consistent with all media. Original black discs or burnt media, also the same with audio CDs. It's not a loud noise but it's just not normal - the laser sounds like its a little laboured.

I've literally just realised it sounds like a cricket!! The noise only kicks in once the laser is focused.

 

OK, I just swapped over the lasers from another PSOne and I can confirm that it's not the laser that's at fault. Hmmmm, strange!

 

Check your solder points. There are 2 revisions of the PM-41 board which are slightly different. It's difficult to see from your picture but your 2nd wire looks like it's soldered wrong.
Also, is pin 8 soldered to GND?

 

OK I will do over them again and report back. I've found another diagram with different areas for #1 and #8 so I will try them and see if that makes any difference.

 

I have removed the chip and the laser is quiet again. I'll redo it now...

I have been using this diagram:



I am using kynar 30 awg wire for all of the points, is this OK?

Once again any info much appreciated

Thank you!

 

There is no reason at all that a properly installed chip should/could cause the laser to be louder. It just doesnt connect to anything that could cause that.

 

That diagram is flawed.

I guess the author wanted to make a PM-41 diagram but only had PM-41 (2) so he took a sharpie and put a line over (2)
which is a pretty dumb thing to do as it obviously doesn't change the layout of the board and creates confusion.

If you have a PM-41 (2) use this schematic:


This is for PM-41:

 

The lines arent there to make it a non (2) board.

Also, your top picture is wrong for point 2.

 

I shall try with the alternative points on the other diagram and see how it goes, thanks for the info

 

As Bad_Ad said, the point that pin 2 is shown wired to on the later diagram is wrong - it should go to the middle resistor, as was the case with the original one. Having said that, it might well still work OK.

The problem with the original diagram is that the supply on the PIC has been wired directly to the output of the power supply - which is about 7.5V. Since the rated operating voltage of the chip is between 3.0V and 5.5V and the absolute maximum supply voltage is 7.0V this is clearly not a good thing.

 

OK my mod is currently soldered to the middle resistor so I will leave it be, I will move my #8 to the alternative diagram and see what happens. It's all good fun

 

@Bad_Ad84: Why is the line over (2)?
---
Hm. So I have a flawed diagram then? Damn. I have to check my SCPH-102 and remedy the issue if I soldered it wrong.

Edit: Nope, it's all good. I have a PM-41 (not 2) so I used a different diagram anyway.

 

It probably wouldn't matter anyway - those 3 resistors connect the serial data link between the mechcon CPU and the CD DSP, and the pins go <DATA><LATCH><CLOCK> - so soldering it to the 3rd pin rather than the middle one will just change the point the modchip detects that commands are being sent to the DSP from the end of the command to the start - but the convention is that you use the latch line, probably because it's a much wider pulse than the clock and easier to detect in software.

I just tried it on a SCPH-9001 using the MM3 code, and it doesn't appear to make any difference, even with sensitive games like the JP Dino Crisis.

 

I've just realised that the laser noise goes away if I remove wire #6... Maybe I should try replacing the capacitor that it connects to?

 

Result - I soldered #6 to the other side of the capacitor, and it now works flawlessly, quiet, normal sounding laser and everything is booting!


Delighted!

Strange though!

 

Good to see that you're problem is solved!
I've had this same problem too, but my problem was because a wire was not correctly soldered... :/

 

haha yeah, probably my soldering is to blame, although I can honestly say it looked fine, I'm slowly getting better!

Anyway for now, I am happy to have a modded PSOne that I have done myself all games I tried booted and disc drive sounds nice and healthy!

Any experts know if it matters that I connected wire #6 to the other (left) side of the capacitor shown? I'm hoping it doesn't matter and I can leave it be with no side effects!