PS1 With No Laser Beam

I have a PS1 that I got cheap a while back. It's an SCPH-7502. The laser moves along the track no problem because if I move it out, it moves back in again when I power on the console and you can hear it clicking because it's trying to focus. But there's no red beam emitting from the laser.

Is it likely to have a dead diode or is that unlikely and there's more chance of a bad regulator or something? I have a multimeter but I'm not sure where I should be testing.

thanks.

 

These lasers emit near infrared (iirc). For that reason and for safety, you should check this with your mobile camera only.
It will clearly see the infrared light, if there's any.
Also, if the disk starts spinning, that's a sure sign that the laser works.

 

I was just learning about this but for gamecube. This video should help you if it’s a laser intensity problem

 

It doesn't spin it just does them 2 little rotations the same as when there's no disc. I've done a lot of repairs on consoles and I never actually look into the beam directly but only from an angle just enough to see a red dot through the disc etc.

I've checked it with my phone camera though and there's literally no sign of any beam from the laser. It was set to 800ohm when I tested it with the multimeter.

Edit : This video shows there's no beam at all being emitted

 

Is that video from your Playstation?

 

Well yeah, that seems to be dead then ;p

 

Yeah that's mine. I'm assuming it's just a dead diode in the laser itself then as everything else about the drive seems normal. Even the way it's trying to focus. I already have another drive ordered but just wanted to clarify whether it was the laser itself or a power/PCB issue.

 

It’s possible that one of the tabs on the spindle hub broke like they usually do and landed inside the laser. Happened to one of mine

 

OK so i got a brand new drive and that still refuses to light up so to no surprise now, there's something wrong with the PCB and I have no idea what it might be.

Edit: Q609 seems to cause that problem but how could I test it. Just check the voltage between the 2 legs? Also it's a very small component I'd likely have a bit of trouble soldering a new one on.

CN702 pin 12 has 3.4v when I test it. I'm not sure what's broken but everything else works except the laser beam. Even the focus works as you see it moving up and down.

 

Are these resistors under L701? None of them show any continuity through my multimeter and there was a lot of green gunk around that area near pin 1 that I had to clean.

 

You found your problem.
This section is the highly sensitive CD RF amplifier. It looks like you knocked off 2 components but even if that's stock, the corrosion in the area means this'll never again produce good signals.
Get a new board, this one is gone :/

 

I figured that's likely. It looked like that stock but yeah the corrosion is a killer. I'll just buy another PS1 instead so but now I have 2 spare drives and a power supply basically.