PS1 PSone PM-41 (2) A modchip problem

[GetTheKnife]

Good morning, I have a PSone with a PM-41 (2) A, yesterday I soldered a onechip using this diagram http://www.fatcat.co.nz/psx/install/102/pm41_28w.html . Now it reads the backups and originals but there is a slightly problem, with the modchip the laser is working "harder", has some weird noise. I removed the chip and the noise disappeared, what could be the problem?

 

[GetTheKnife]

@Trimesh Any thoughts?

 

[NeC5552]

Sadly this is one of the side effects of using ONECHIP. I have 2 PM-41 (first generation) based PSOnes and it does the same. The only thing I can suggest is adjusting the laser to keep the noise at a minimum. I adjusted the laser on both of my consoles and both read ~99% of my discs.

 

[GetTheKnife]

Sadly this is one of the side effects of using ONECHIP. I have 2 PM-41 (first generation) based PSOnes and it does the same. The only thing I can suggest is adjusting the laser to keep the noise at a minimum. I adjusted the laser on both of my consoles and both read ~99% of my discs.

Thanks but I don't have any equipment for adjusting the laser, reading this thread https://assemblergames.com/threads/psone-laser-louder-after-mod-chip-install.50846/ @Trimesh says the diagram is wrong, and two people said to solder on the other side of capacitor on point 6 and it solved the noise, just want trimesh opinion since it has him that suggested.

 

[NeC5552]

Strange, the last time I tried TriMesh's suggestion to use the other side of the cap, none of the games (be it a backup or original) loaded for me, and that's on 2 PM-41s I tried, both with ONECHIP.

 

[GetTheKnife]

Strange, the last time I tried TriMesh's suggestion to use the other side of the cap, none of the games (be it a backup or original) loaded for me, and that's on 2 PM-41s I tried, both with ONECHIP.

I see, maybe MM3? But that can't play import games and that games with anti modchip right?

 

[NeC5552]

Yeah, it's kinda the same as if I used a classic 4 wire chip.

 

[GetTheKnife]

Yeah, it's kinda the same as if I used a classic 4 wire chip.

The only advantage of using onechip on a PAL psone with the pm41 (2) is the ability to play imported games over MM3 right? What I'm not sure is if the mm3 is stealth for the games that have the code to detect modchips... Also on MM3 the laser noise is not present as I understand.

 

[Trimesh]

The only advantage of using onechip on a PAL psone with the pm41 (2) is the ability to play imported games over MM3 right? What I'm not sure is if the mm3 is stealth for the games that have the code to detect modchips... Also on MM3 the laser noise is not present as I understand.

OK, the PM41 is generally pretty flaky with modchips - as already suggested, you could try moving the wire to the other end of the cap, but it may or may not work, and there is no clear pattern to it.

In fact, you sometimes get that noise from the optical pickup with MM3 too - but it seems much less common than it is with OneChip.

To answer your other question, yes, the MM3 is a stealth modchip - and in a lot of cases the modchip detection code intentionally disables itself on PAL machines anyway.

You can also install two chips - use the OneChip with just power, ground and the wires to the boot ROM for the NTSC patch and the MM3 for the actual modchip function. Note that the boot patch forces the console into NTSC mode, so the boot screens are displayed in 60Hz video.

 

[GetTheKnife]

OK, the PM41 is generally pretty flaky with modchips - as already suggested, you could try moving the wire to the other end of the cap, but it may or may not work, and there is no clear pattern to it.

In fact, you sometimes get that noise from the optical pickup with MM3 too - but it seems much less common than it is with OneChip.

To answer your other question, yes, the MM3 is a stealth modchip - and in a lot of cases the modchip detection code intentionally disables itself on PAL machines anyway.

You can also install two chips - use the OneChip with just power, ground and the wires to the boot ROM for the NTSC patch and the MM3 for the actual modchip function. Note that the boot patch forces the console into NTSC mode, so the boot screens are displayed in 60Hz video.

Is there any explanation where that noise comes from, is it damaging the chip or console in long term like giving shorts or over voltage? About soldering to the other side of Capacitor people said the console becomes very picky with the cds for some reason. Also on diagram the point two should be on the middle Capacitor and not on the right one loke the diagram correct?

 

[Trimesh]

Is there any explanation where that noise comes from, is it damaging the chip or console in long term like giving shorts or over voltage? About soldering to the other side of Capacitor people said the console becomes very picky with the cds for some reason. Also on diagram the point two should be on the middle Capacitor and not on the right one loke the diagram correct?

It's coming from the lens in the optical pickup - there are two sets of electromagnets in there, one of which moves the lens up and down (for focus) and the other which moves the lens in the same axis as the sled (for tracking) - the noise is coming from the tracking actuator. I can't say if it causes long-term damage, since if I ever found a machine that did that then I fixed it.

For the pin 2 connection, either will work - it just changes the timing of when the SCEx injection ends. The middle position is slightly later and the position on the right is slightly earlier - there were some reports of the modchip detection triggering with certain games with the wire in the middle position.

Note that all these chips degrade the performance of the tracking servo to some extent, because they effectively ground out the tracking signal about 50% of the time - if the optical pickup is old and tired, this can result in difficulty reading discs.

 

[GetTheKnife]

It's coming from the lens in the optical pickup - there are two sets of electromagnets in there, one of which moves the lens up and down (for focus) and the other which moves the lens in the same axis as the sled (for tracking) - the noise is coming from the tracking actuator. I can't say if it causes long-term damage, since if I ever found a machine that did that then I fixed it.

For the pin 2 connection, either will work - it just changes the timing of when the SCEx injection ends. The middle position is slightly later and the position on the right is slightly earlier - there were some reports of the modchip detection triggering with certain games with the wire in the middle position.

Note that all these chips degrade the performance of the tracking servo to some extent, because they effectively ground out the tracking signal about 50% of the time - if the optical pickup is old and tired, this can result in difficulty reading discs.

Ohh I thought the reason to put in the middle capacitor was because the other would give over voltage to the chip, so I guess you recommend leaving on the right instead of the middle? On other thread you said to put it on middle. What did you do to fix it? The psone I have was rarely used.

 

[Trimesh]

Ohh I thought the reason to put in the middle capacitor was because the other would give over voltage to the chip, so I guess you recommend leaving on the right instead of the middle? On other thread you said to put it on middle. What did you do to fix it? The psone I have was rarely used.

I honestly don't think it matters - there is no signal on any of those pins during the time that the mechacon is checking for the SCEx data - once the SCEx string is detected, commands are sent to the CD DSP, and terminated with the XLAT/ pulse - so the only effect of hooking that wire to the end resistor is changing the timing of the end of the SCEx data.

I also have to say I'm getting a strange feeling looking at the install diagram linked in the first post. I think it's wrong - it's showing the wire to pin 5 of the PIC connected to pin 76 of the CD controller, and I think that's supposed to be pin 84 - which is the testpoint at the right end of the same row (just below the pin 88 marking).

I might be hallucinating, but try moving the wire there and see if it improves anything...

 

[GetTheKnife]

I honestly don't think it matters - there is no signal on any of those pins during the time that the mechacon is checking for the SCEx data - once the SCEx string is detected, commands are sent to the CD DSP, and terminated with the XLAT/ pulse - so the only effect of hooking that wire to the end resistor is changing the timing of the end of the SCEx data.

I also have to say I'm getting a strange feeling looking at the install diagram linked in the first post. I think it's wrong - it's showing the wire to pin 5 of the PIC connected to pin 76 of the CD controller, and I think that's supposed to be pin 84 - which is the testpoint at the right end of the same row (just below the pin 88 marking).

I might be hallucinating, but try moving the wire there and see if it improves anything...

Ohh I see, I don't know about pin 5, on all diagrams I have found pin 5 remains the same. So even if it gives a bit more voltage then it's only for short term.

 

[Trimesh]

OK, you (and everyone else) should ignore that comment I made in the other thread - the wire going to the DC Jack is actually connected to the ground pin, not +7.5V - I wasn't paying attention and didn't realize the chip was upside down and thought the wire going to the power jack was pin 1 (+VE supply) rather than pin 8 (GND).

I would be interested to hear if moving the wire to pin 5 fixes the problem though - that should be fed with the WFCK signal, and I'm fairly sure that's on pin 84 of the new CD controller chip...

 

[GetTheKnife]

If someone could try that, it would be great.

 

[NeC5552]

I can try if you want. Just post a picture where do I have to move the wire for pin 5 to. (I usually go by which point it has to be soldered to)

 

[Trimesh]

I can try if you want. Just post a picture where do I have to move the wire for pin 5 to. (I usually go by which point it has to be soldered to)

OK, cool - it might not work, but looking at the circuit it's a definite difference between the way the chip is installed on PU-22/PU-23/PM41 and the way it's installed on PM41 (2).

Both points carry the same nominal frequency (about 7.35kHz) - but WFCK (which was what was being used on the older boards) is adjusted to match the current speed of the disc and RFCK isn't (it's just directly divided down from the clock).

 

[GetTheKnife]

I can try if you want. Just post a picture where do I have to move the wire for pin 5 to. (I usually go by which point it has to be soldered to)

OK, cool - it might not work, but looking at the circuit it's a definite difference between the way the chip is installed on PU-22/PU-23/PM41 and the way it's installed on PM41 (2).

Both points carry the same nominal frequency (about 7.35kHz) - but WFCK (which was what was being used on the older boards) is adjusted to match the current speed of the disc and RFCK isn't (it's just directly divided down from the clock).

View attachment 1652

Awesome guys, hope it works.

 

[GetTheKnife]

I can try if you want. Just post a picture where do I have to move the wire for pin 5 to. (I usually go by which point it has to be soldered to)

Any news on that? I'm going to remove the psone chip on mine, it's reads games bad, for example castlevania sotn it lags and the audio stops randomly for 1 sec or so. It's not the disc because I tried on a older psx fat and works fine.