Gave my PSX a full service! (including DFO install)

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chrisvg
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Gave my PSX a full service! (including DFO install)

Post by chrisvg » February 16th, 2018, 5:38 pm

Thought I'd share some pics of the work I just finished doing on my PSX, quite proud of the progress I've made in recent months. Much cleaner solder work and wire run optimization than the work I've done previously.

Firstly, here's a "before" pic of my PSIO mod install.. I cringe a little looking at the rabbits warren of wires going all over the place. And the hotglue.. oh god damn that hot glue.. what was I thinking?!

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The little white mod is an old school PIC chip that was installed in the machine back in the 90s. Just a simple region injection PIC mod.

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Now for the "after" pic.. Much cleaner I think :)

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And finally, I also installed a DFO (Dual Frequency Oscillator). This little mod replaces the PAL clock generator (this is an Aussie PSX) and now outputs accurate PAL and NTSC timings. On a standard PAL PSX, when you force NTSC output it is slightly out of spec (vice versa for a NTSC PSX being forced to output PAL).

When playing on a CRT this isn't really noticeable, it's only when you start playing with upscalers like the OSSC or XRGB-mini do you begin to notice problems like pure black appearing as dark grey.

This mod resolves this problem by generating the same clocks that a NTSC PSX would. This fixes the subcarrier timing which allows upscalers to display the video output correctly.

Another bonus feature of this mod is that it also forces the GPU to run at the correct speed for NTSC (the difference is very minor, but it is still there). In like 99% of games this has absolutely no effect on gameplay, however of particular note is the Konami Bemani series of games (Beatmania, Guitar Freaks, etc) - these games rely on the vblank timing to match the music tracks up with the button prompts displayed on the screen. If you try playing these NTSC versions on a regular PAL PSX you will find that the button prompts get progressively out of sync with the music which basically makes them unplayable. This mod fixes that timing issue!

Anyway, here's a pic of the mod installed in my PU-18 PAL PSX :)

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Hope someone found this interesting, I was mostly just wanting to make amends for my terrible mod pics I posted when I first got my PSIO a while ago haha!

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keropi
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Re: Gave my PSX a full service! (including DFO install)

Post by keropi » February 20th, 2018, 6:29 am

Very nice, kudos!
can you tell more about the DFO mod? I also live in PAL land and it would be nice to have this - atm I am using a NTSC-U psx that I imported

chrisvg
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Re: Gave my PSX a full service! (including DFO install)

Post by chrisvg » February 20th, 2018, 1:39 pm

keropi wrote:
February 20th, 2018, 6:29 am
Very nice, kudos!
can you tell more about the DFO mod? I also live in PAL land and it would be nice to have this - atm I am using a NTSC-U psx that I imported
The creator of the DFO posted quite a lot of detailed information here and here (you will need to translate from German for the second link, but it has some extra details that are not in the first link). All of the information you need to build your own is included at the above links.

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