SCPH-1002 disc drive voltages

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juz571
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PlayStation Model: SCPH-1002
Location: England

SCPH-1002 disc drive voltages

Post by juz571 » October 22nd, 2023, 1:54 am

Hi all,

Wonder if anyone can help with expected drive voltages at the disc drive connector on a SCPH-1002?

I have the 3.5v and 5v as it should be from Q609

BA6397FP 7.65V on pins 21 and 22
Ch1 out A 3.5V
Ch1 out B 3.5v
Ch4 out A 3.5V
Ch4 out B 3.5V

Then at the connector which goes to the drive I have (from left to right looking from the front) 3.5V 3.5V 4.5V 2.4V
When I press the lid switch none of these voltages change. Do these voltages seem correct at this connector? I would expect some kind of change when the lid switch is pressed, as this tells the disc drive to spin doesn't it?

Thanks in advance for any assistance.

Juz

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nocash
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Post by nocash » October 22nd, 2023, 5:05 am

juz571 wrote: October 22nd, 2023, 1:54 am I would expect some kind of change when the lid switch is pressed, as this tells the disc drive to spin doesn't it?
As far as I remember, yes, it should spin (at least for a short moment, and then stop spinning if no disc is detected). And, as I remember, Sony didn't bother to start the spindle motor until after displaying their yellow <S> logo.

In practice, I have just checked... it seems that my disc drive doesn't spin at all, no matter what, it's totally dead, and can't boot (I am normally booting my code via parallel port cable, so I hadn't noticed that problem yet) (another problem in my console is that it doesn't react to the Reset button until the console has warmed up, that need-to-warm-up thing looks like a typical capacitor related problem).

PS. One thing that is still working in my console: When pressing the drive door switch, the lens is moving up and down twice. And the laser is also emitting some visible red light during that process (a tiny red dot, visible in a dark room).

juz571
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Post by juz571 » October 22nd, 2023, 5:17 am

PS. One thing that is still working in my console: When pressing the drive door switch, the lens is moving up and down twice.
I have the drive removed at the minute for testing purposes, but it was the same when it was all together. lens moves up and down twice, but disc doesn't spin at all though

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Post by nocash » October 22nd, 2023, 8:27 am

I have replaced some capacitors. The 100uF 6V in front middle looked most visibly bulged, but replacing it didn't change anything. Some of the three 47uF 16V on left side also looked bulged, replacing them seems to have fixed the issue with my reset button (yeah! that issue was bugging me for a while), but it didn't help on the cdrom problem.
I could try to replace more caps, but it would be quite a mess (I have only old through-hole ones at home, and most are so tall that they could be mounted only horizontally).

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Post by nocash » October 23rd, 2023, 3:34 am

The main problem seems to have been a dirty lens.
That is, the spindle motor is NOT started at all when not sensing reflections from the disc. Either because no disc is inserted, or because of too much dirt.
The spin-up and disc detection is now working okay... booting does still hang... I guess it just needs a bit more cleaning (than just using some spit on a paper towel).

About the capacitors. I have a multimeter that claims to be able to measure capacitors... it's only working when desoldering the capacitor (or at least one leg)... and it's very slow when measuring large caps in uF range (the poor thing keeps claiming to read values in the nF range, until showing the correct value in uF range after 5-10 seconds).

Anyways, going by that multimeter readings, the old 47uF capacitors seem to have been intact (now I don't know why the reset button didn't work until after replacing them). I got no measurements for the 100uF one (maybe the multimeter just can't measure that large values).

And a different capacitor related issue: The huge 400V capacitor on the power supply board next to the 220V connector did have broken solder points. After fixing that, the video looks more stable (previously, it did show gray stripes during disc detection).

juz571
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PlayStation Model: SCPH-1002
Location: England

Post by juz571 » October 30th, 2023, 2:06 am

So I’ve sorted it, thanks mainly to an excellent guide from Jonathan Dupre. First thing I checked was the Focus bias voltage, and it was WAY to low @ 1.24V. Wound it up to 1.6V and bingo, disc spins and reads. Haven’t tried a copied disc yet, as I don’t have any, but FFVII is up and running. 👍

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