Worklog PS1 Native VGA mod (15khz)

[Y2K]

I've done the mod, but it is not working for me, I've followed the old replies for the R G B signal and everything seems to be good, but no signal on my crt... Maybe there is some sort of problem on the board because I've noticed that pin 157 of the gpu is missing (?) and there is a bridge near, I've read that.. That pin controls the H signal?

Several things you need to check here:

1st off, please make sure the display you're using accepts 15KHz sources (aka 240p, 480i), most PC CRTs that accept VGA do not. You'll need a scaler if you want to use this on those.

2nd, please clear any sorts there might be, especially when it comes to the H/V sync lines.

3rd, pin 157 is likely important, its the NTPL line going to the video DAC - this is what tells the Video DAC to display a PAL or NTSC signal. Without it, I'm not sure how the Video DAC will behave, so you may need to solder a wire from the remnants of pin 157 to pin 13 on IC502. if theres no remnants left, you may be able to file away part of the package where pin 157 was to expose the leadframe, and solder to that.

 

[DarkDuckling]

thank you for all the help guys,you were really nice,sadly I broke my ps1 accidentally...some bits of solder came in contact with the gpu pins and it is a whole mess,I wasn't really carefull,eitherway I bought another ps1 and it's a 5502 model! there is just a proble here...the vias for H and V sync...seem to be..not present? like they were torned off the board :0,are there other vias for them? thank you!

 

[Stitches]

thank you for all the help guys,you were really nice,sadly I broke my ps1 accidentally...some bits of solder came in contact with the gpu pins and it is a whole mess,I wasn't really carefull,eitherway I bought another ps1 and it's a 5502 model! there is just a proble here...the vias for H and V sync...seem to be..not present? like they were torned off the board :0,are there other vias for them? thank you!

If the traces are gone, your only option is to solder to the 2 GPU legs that fed those traces