PS1 SCPH-1001 Ressurection

Hi, I found my grandfather's old Playstation 1, one of the oldest models (SCPH-1001)

I plugged it in and the power led lit up, however there was no video output and the cd assembly would not spin a disc.

I tore it down, the power supply seems to be just fine, but when I pressed down the lid sensor the cd assembly motor did not spin up, however I noticed there was a faint light in the laser, but not as bright as it should be.

So I tore it apart even further and got the mainboard out, underneath the mainboard I found a little metal decking screw, so I think the screw must have fallen into the console somehow, rolled under the mainboard and zapped some shit.

Can this PS1 be saved?

Also, there seems to be no visibly damaged components, and the solder looks fine.

I'm not very knowledgeable on electronics, but if I find a service manual would it tell me some points to check with a multimeter to start tracking down what's wrong?

I decided to check the power supply voltage just in case, here's what the voltage should be, supposedly:

Purple = 3.4V - Drop to 0V to reset console.
Blue = Ground
White = 3.5V
Yellow = Ground
Orange = 3.5V
Red = Ground
Brown = 7.6V

Here's what I'm getting:

Purple = 0.21V
Blue = Ground
White = 3.63V
Yellow = Ground
Orange = 3.59V
Red = Ground
Brown = 7.26V


So, I take it this means it is the power supply?

 

I would try the PSU first, but if that wouldn't work, I would probably give up. It's a real pain trying to diagnose some PS1 problems.

 

Check the fuses

 

These are fuses, right? There seems to be all kinds of surface mount fuses.

 

I think it's probably a fuse, too - but start by unplugging the power cable to the main board and checking to see if the reset line (purple) goes high with the main board disconnected. If it doesn't then the PSU is bad - if it does, then it's the main board (and probably one of the fuses).

The fuses are easy to spot if you are familiar with the PlayStation - they are close to the PSU connector on the main board and are marked with numbers like "20", "15" or "50" - they also normally have arrows pointing to them with designations like "PS603". Just set your meter to volts, ground the negative lead and then check the voltage on both ends of all the fuses - if they are OK, they will have the same voltage on both ends - if they are blown then they will have a supply on one end about about zero volts on the other.

 

Thanks, I checked the reset line on psu, here's what I got: 0.22v when switch is not pressed 0.00v when switch is pressed Then I checked all the fuses with the numbers on top on the mainboard near psu connector, every one of them seemed fine (same voltage on either side) except for the one marked "50" on top. on that fuse, one side read ~3.5v and the other side read ~0.90v So, that fuse is probably bad?

 

Yes
Ah and don't replace with a wire!

 

ok

Just out of curiosity, why can't it just be bypassed with a wire?

I have one other scph-7501 that is totally destroyed beyond repair, I'm going to test the "50" fuse on it and if it's good, I'm thinking that I could use some kynar wire and make an inline fuse out of it if I don't destroy the fuse getting it off the board.

Would that work?

Ok, I checked and that "50" fuse on that ps1 is bad too. It has some good "20" and "15" fuses, though.

 

Because if you use a wire instead of a fuse and your psx have a fault component or a short somewhere you will end destroing a "more important" component (cpu, audio IC ecc) instead of the fuse. So you will can easly say goodbye to your psx...
Use your best method for you skill, but the important thing it's you must replace fuse with a fuse.

The wire bypass fuse solution it's a mania from unexpert or "wanna cool" people from the web. It's the most stupid fix to do, and here (and on the web also) you can find topic where people who have given "the coup de grace" to their console, like for example, shorted charger for the PSP.
PSP don't charge, fuse bridged. Connected again shorted charger, charge ic fried, ergo killed psp mobo because changing the ic it's not a thing that you can replace easly like fuse....

 

Ok, thanks.

Would a "20" or "15" fuse work to replace the "50" fuse?

 

yes and no,
Because a fuse marked with 20 can "tollerate" less current load from a one marked with 50...
You can do a temporary test, but expect the the fuses blown again after some time or immediately, all depends on the current load

If i'm not wrong
"50" should be a 2A fuse and "20" should be 1A fuse

 

Yep, you were right. I put a 20 in there and tested by pushing the lid sensor down and the laser went towards the motor for a split second and then the fuse must've burnt because it won't move again.

I wish i had a fuse i could replace it with laying around in some junk pile.

Well, I checked the fuse I put in there and it didn't actually blow, so it was doing fine.

That means, something else is bad, no idea where to look now.

Going to see if it actually boots up now and from there check whether the cd assembly is actually getting power.

 

You should check the other fuses, and for things like the voltage regulator, the cd drive chip etc ...
There's a short or other component that causes trouble, or maybe it's the psu...
Make a detalied photo...

 

Well, I tore that fuse out and put one in that would work, when I went to reassemble I looked at the cd assembly's ribbon cable and noticed above the contacts it had been folding in one area and one of the wires inside severed.

So, I stole a cd-rom from a junk 7502 and clipped the plastic on the bottom to get it to sit right on the 1001.

It all hooked up fine, the only problem now is that when I power up and push the lid sensor, the laser clicks looking for a disc or something, but I assume it can't read anything because the spindle motor doesn't even attempt to spin the disc before that happens.

I don't know how to check any of the chips, though. Can you do it with a multimeter?

Just tested, removing just the 4 pin plug for the cd drive, the laser still lights up, and clicks moving up and down. Whatever is wrong is before the 4 pin plug.

edit: nevermind, that 4 pin must just be to supply power to the worm motor and spindle motor, which it's doing fine (~3.56v on each pin)

It's whatever should be telling the spindle motor and worm motor to work that is failing to do so.

 

Sounds like the BTL driver has blown up - it's a SOIC device normally mounted on the back of the board with a number something like "BA6398FP" (it might not be exactly this - the precise part changed frequently with board revisions) - it's easy to replace with a hot air station, but not so easy without one.

One problem is that I'm pretty sure the PU-22 board used a different chip (still BAxxxx, but not the same number), so you won't be able to use one from that.

 

Yes, trimesh is right. That's the cd drive chip problem that i've stated before...
You can only fin one from the web or from a broken pu8 or pu7

 

Well, thanks for the help you guys. I will more than likely look for one of those chips and attempt to replace it.

I want to fix this console more for the memories attached to it than anything else.

It makes sense that something on the backside was ruined since the screw rolled under the mainboard.

If I can get a hold of one, I was thinking instead of buying hot air tools, do you think I could use some high temp polyimide tape to isolate the chip and protect the components around and use a hot air gun on low to replace the chip?

I don't think the back side of the board is nearly as densely populated as the front.

The chip is in fact "BA6398FP", where as the chip on the 7501 is "BA5977FP".

 

no, hot air gun method it's another "wanna cool" DIY method by the web
PSX mobo it's very fragile, and you will easly end destroing it. Better cut all chip pins with cutter, remove the legs with solder and after, clean all and solder the new component...

 

Ok, I never thought of removing a chip that way. I'm not the best at soldering, looks like I'm going to need a new tip since the one I've been using is trash.

I found a good place to buy the chip, $1.39 USD each, so I'll probably get a few and update this thread when I've colossally failed at replacing the chip.

 

Cutting the leads is normally the safest approach - just make sure you have fine-point cutters and snip the leads as close to the package as you can.

Then just use the iron to lift the leads off the board using the surface tension of the solder. Since this chip has a heatsink on the middle pins, you will have to lift that separately (once the other pins are removed you can just heat up the solder on one side and lift the chip).