PSone SCPH-10x seems picky

I grabbed a nice looking PSone mini which didn't read the one burned cd-r that came with it. Since the installed modchip was using way long wires, had cold joints and was fixed in place using painter's tape I decided to replace it. According to some info on here the Mayumi v4 was the prefered chip to use, with MM3 being a good second.

It seems the install isn't as good as I'd hoped it to be.
The console doesn't seem to care much for my verbatim CD-R discs written at 2.4x - it just goes to the BIOS menu where you can choose between memory card/audio player. Another type of disc comes up with a screen saying "please insert PlayStation format disc".

Install below is according to a PM-41 A diagram but I've found much closer VDD/GND points to reduce some wire length, but this seems to have made no difference at all.

Not sure what the best course of action here is. I'm using a 12C508A because farnell had them in stock for next-day and it would mean not having to use any ported/less tested firmware. Should I have positioned the chip elsewhere? Better to try MM3 firmware? Possibly bad optical? Any other expert's (@TriMesh ?) advice I should heed?

 

hi zz , try and let the PSone boot to the Bios menu screen then close the lid and hopefully games should boot then. I had a issue where from cold boots were also on and off , but i then did the method i mentioned and i got 11 out of 11 successful boots with a MM3.

 

From what I know the best modchip for SCPH-102 (and version 2) is OneChip.
SCPH-102 is the european model.
What do you have?

P.S. by the way this is version 2 motherboard (PM-41 (2)): https://static.quade.co/wp-content/uploads/2017/09/IMG_20170924_141404.jpg

 

Ah so that's how it works, thanks. Indeed much higher success rate that way!

Hadn't heard about OneChip before but I do have a PAL console so I'll change the firmware to that one.

Update: wow, onechip is great. Always seems to work 1st try whatever I throw at it.

 

Onechip is the only way to direct boot imports on a pal psone.

Also, decoupling cap often fixes the issue you were having, in my experience at least.

 

Agreed that the PIC should have a decoupling cap.

For some reason some games seem to display in black/white whereas others work in color over the composite cable. Unfortunately no option of doing RGB at the moment, but I'm waiting for hdretrovision cables to be in stock somewhere eventually.
I did read about forcing the video mode to PAL by adding a wire between pin 13 of a video encoder chip (IC204 or IC502 on PM-41 A) and GND or 3v3. After trying both settings, all my games are in black and white and none have color anymore.
Is there a fix for this? It's a PAL console so PAL50 and PAL60 both seem reasonable modes to me. Anything else I could try here?

 

Sorry to ask you this Bad_Ad84 but what is decoupling cap and how to use it and why with OneChip?

Thanks!

 

It's a kind of power line filter for electronic components. You'd just solder a capacitor over the Vdd and Gnd pins.

 

If you don't use a decoupling cap can you tell me what are the simptoms?
Thanks zzattack!

 

It may not boot games if you don't use it. Some chips and consoles function better with it, some function fine without it.

 

I understand now.
For example, my SCPH-102 with board PM-41 (2) (A) sometimes doesn't recognize the game (9 of 12 succesful boots with OneChip)
Do you think this can be the case or something else?

Thanks!

 

I wouldn't worry about 9/12 boots to be honest. Seems fine to me. Make sure disc and laser are also cleaned.

 

If I want to solder the decoupling cap can it influence something to work bad?

Thanks!

 

No, it wont make it worse.

 

Thank you Bad_Ad84.

 

On a PAL PS1 using the new clock generation (I.E. PU-20 and later) the color subcarrier is always the "correct for PAL" 4.43MHz - so when you switch to NTSC mode without any video mods the output is NTSC but with a 4.43MHz subcarrier (AKA NTSC4.43). This is not a standard mode, but is still widely accepted by Euro-spec TVs because it was used back in the day by a lot of multiple-standard VCRs when playing back NTSC tapes.

If you force the encoder into PAL mode by cutting the trace and installing a jumper then it will output PAL60 in NTSC mode. This mode generally has better support on older TVs than NTSC4.43.

 

Sorry to ask this but what value must have the decoupling cap?
I have the SCPH-102 PAL with PM-41 (2) (A) board.

Thanks!

 

edit: Bad_Ad84 had the right one.

 

100nf also known as 0.1uf marking is 104.

 

Using for reference this http://www.fatcat.co.nz/psx/install/102/diagrams/pm41(2)8w.jpg and http://ww1.microchip.com/downloads/en/DeviceDoc/40139e.pdf I must solder the positive leg of the capacitor to pin 1 (Vdd) and the negative one to pin 8 (Vss) on OneChip, correct?

Thanks!