Alternative PS1 CD Rom drive found.

General information to do with the PlayStation 1 Hardware. Including modchips, pinouts, rare or obscure development equipment, etc.
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Post by alexfree » December 26th, 2022, 12:13 pm

Vr-Mode wrote: December 20th, 2022, 12:06 pm Just tested two different brands of CD-RW's. Sony and Memorex and all the laser did was click while trying to spin the disc.
I think it would be worth checking with a Verbatim DataLifePlus CD-RW, I might pick one up.

I am aware that tweaking the drive would probably make just about any CD-RW work as shadow mentioned. I don't really want or need to do that though, it's just a curiosity, I want to see if with no tweaking it 'just works' with a high-quality, very-reflective CD-RW disc.

Something I have noticed, the KSS-213C can read 24x (max burn speed) Verbatim DataLifePlus CD-Rs just like, i.e. my PS2 can. I've never been able to get even a 16x speed burned CD-R to be read by a real KSM-440AAM-KSM-440BAM PS1 CD drive on the other hand. No issues with the 24x burned CD-R though with the external.

I've always burned PSX CD-Rs at the lowest speed my burner can do (10x). It really is unfortunate that most newer burners now can only burn at 16x and higher (which wouldn't work on a PS1 with a regular drive in my experience).

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Post by alexfree » January 13th, 2023, 9:58 am

After using these drive for a bit, I have some more info I can share.
My SCPH-1000 still works really well with it. There is something really weird about picking up the wobble on the super old console models that have manual Bias and Gain however. Sometimes it just doesn't pick up the SCEI signal. This is not that big of a deal though because you only need to do this once when you boot or spin up a Japanese psx disc. It again reads the disc contents perfectly, just the actual wobble is iffy.

All my SCPH-1001s just can't pick up the wobble at all with the drive. No amount of bias and gain tweaking has made it work once on 2 different consoles of the same model.

My PSone SCPH-101 works with the drive every time to pick up the wobble.

So I think this should be considered. If you console has manual Bias and Gain adjustments these drives may not be able to pick up the wobble. The early PU7 at least can pick it up most of the time. My PU8s have never picked it up.

Any Console with auto bias and gain however will work every time to pick up the wobble.

If your console is chipped, picking up the wobble doesn't matter in this case. If you have a 1001 or any USA or PAL console that can be unlocked, it doesn't matter as well I'd you use a Cheat Cart to boot into i.e. tonyhax international rom or use something like freepsboot since the drive just becomes unlocked immediately anyways.

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Post by david4599 » March 7th, 2023, 12:04 am

Shadow wrote: December 19th, 2022, 1:00 am
alexfree wrote: December 18th, 2022, 4:21 pm I just had a thought. I wonder if this external could possibly read CD-RWs.The answer seems to be maybe, I have to get some: https://audiokarma.org/forums/index.php ... st-8342955 . I bet Verbatim DataLifePlus CD-RWs would have a good chance at working.

Unrelated, but I found a data sheet on the KSS-213C CD drive (attached). Not a hardware person, but this may be interesting to others.
To read CD-RW you need to increase the laser diode power which then makes reading genuine PSX games a problem. The best solution would be to make some sort of automatic gain controller which is triggered on either power on or reset. The easiest solution would be to just use a toggle switch and some resistors :)
I have read multiple times that it is not recommended to increase the laser diode power because it will put more strain on it and reduce its lifespan. A while ago, I tested this method on my PS1 and the CD-RW could be read, at least for a few seconds. I didn't try to go further and boot a game because I didn't want to damage the laser diode. Maybe the one of the KSS-213 is more robust and can handle a bit more current without lifespan issue but I am doubtful about that.

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Post by david4599 » March 7th, 2023, 11:16 pm

Oh, I realize this was already mentioned in the link alexfree posted that I didn't read...

Anyway, I did a bit more research to play CD-RW on PS1 and there is maybe a way to achieve it without increasing the laser diode power by adjusting the receiving gain but it would need to replace the RF amplifier chip that has no gain control by something like the CXA2570N that has a RW/ROM switching mode on its pin 12. That would require a PCB adaptation so not as easy as turning a potentiometer but that would be an interesting experiment to try unless there is something else preventing that. Here is the link where I found this method (in french): https://www.latavernedejohnjohn.fr/arti ... 2/#com2711

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Post by david4599 » March 24th, 2023, 5:08 am

alexfree wrote: December 4th, 2022, 6:55 pm The converter board design seems pretty simple, are there any hardware people that can explain how it works? I got these images from a review, but I actually ordered quite a few of these things while they were still in stock.
I looked at this board a bit and it is actually simple to understand once we see the PS1 and KSS-213C schematics that we can find easily.
PS1_optical_part_schematic.png
KSS-213C_schematic.jpg
I don't have this alternative drive but from the pictures, apart from the simple re-routing of the signals to adapt the pinouts of the connectors, here are the only changes:
- The limit switch of the KSS-213C seems to be part of the structure, not of the moving pickup itself like the PS1. It means this switch is connected to the motors connector (black and red wires) and has to be routed on the KSM-440 flex cable on the PS1 (pin 12)
- The 4 resistors allow to convert the 4 individual A, B, C and D photodiodes outputs from the KSS-213C into the 2 signals A+C and B+D needed for the RF and Focus Error signals. In the CD players equipped with the KSS-213C (like others having the A to D outputs available), this merging part is located either on the motherboard or inside the RF amplifier chip but for the PS1, this is already done in the pickup.

Here is the schematic I made based on the pictures + PS1 and KSS-213C schematics:
KSS-213C_To_PS1.png
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Post by alexfree » March 28th, 2023, 6:18 pm

david4599 wrote: March 24th, 2023, 5:08 am
alexfree wrote: December 4th, 2022, 6:55 pm The converter board design seems pretty simple, are there any hardware people that can explain how it works? I got these images from a review, but I actually ordered quite a few of these things while they were still in stock.
I looked at this board a bit and it is actually simple to understand once we see the PS1 and KSS-213C schematics that we can find easily.

PS1_optical_part_schematic.png
KSS-213C_schematic.jpg

I don't have this alternative drive but from the pictures, apart from the simple re-routing of the signals to adapt the pinouts of the connectors, here are the only changes:
- The limit switch of the KSS-213C seems to be part of the structure, not of the moving pickup itself like the PS1. It means this switch is connected to the motors connector (black and red wires) and has to be routed on the KSM-440 flex cable on the PS1 (pin 12)
- The 4 resistors allow to convert the 4 individual A, B, C and D photodiodes outputs from the KSS-213C into the 2 signals A+C and B+D needed for the RF and Focus Error signals. In the CD players equipped with the KSS-213C (like others having the A to D outputs available), this merging part is located either on the motherboard or inside the RF amplifier chip but for the PS1, this is already done in the pickup.

Here is the schematic I made based on the pictures + PS1 and KSS-213C schematics:
KSS-213C_To_PS1.png
Literally thank you so much. I don't know anything about hardware but I had a feeling it was a simple design like this.

I really, really hope that in the future it will be possible to manufacture completely new PSX CD drives which fit internally into the console using this kind of information. That is the ultimate goal in my opinion. Refurbishing 30 year old CD drives is nice and all but what about in 50 years? How many refurbs will actually work then? This stuff is getting really old and wasn't high quality to begin with. There is definitely a reason the PSX was $399 on launch day while the Saturn was $499... My September 1999 Dreamcast is a beast but most PSXs from the same period need refurbishment.

The thing I really like about this project is that it shows, for the first time. that we can use different hardware as a CD drive in any PSX. This is just the beginning.

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Post by david4599 » May 25th, 2023, 9:14 am

So, I actually bought this drive recently and I am quite doubtful on its build quality (and more generally on "bad" made in china replacements).
There are several things I noticed on the one I have:
- The spindle hub is not great, this makes the disc spinning a bit wobbly and the reading of data is then less reliable.
- The thin contacts of the flex cable start to come off quickly (only after 3-4 careful insertions in the 5502 connector).

Also, nocash was quite right about sled steps:
nocash wrote: December 14th, 2022, 4:20 am My main concern would be if the sled is moving the same distance per step (I don't know if that's somehow standarized for all compact disc drives, or if it needs to be specifically matched to psx retail drives).
If the steps are too far off then it would fail with timeout, if the steps are too big or too small then it would take longer and require more attempts to find sectors, and if they are too big then the sled might additionally hit the outer edges with some nasty "krrrrrrrk" sound if the wheels keep spinning - I hope that doesn't happen?
The sled is moving slower than the original one and that's usually fine but there is an issue when booting games that have their main executable (weirdly) located at the end of the disc e.g. Peter-Pan PAL SCES-03711.
The second time the disc spins at 2x, the drive will seek at the end to read the exe.
Once it has finished reading, it will slow down the disc to 1x and seek in small steps all the way until it finds the lead-in to read the wobble again.
On the original drive, this seeking part takes about 5-6s but on the KSS-213, it takes 9-10s which is a bit too much and most of the time, the drive times out and stops the disc.

Anyway, there was already some discussions and schematics on how to adapt the KSS-213 that I didn't see when I reversed the board.

https://strefapsx.pl/forum/psx-mody/ada ... msg100975/
https://segasaturngroup.proboards.com/t ... -sony-213c
https://www.elotrolado.net/hilo_mod-ada ... s1_2466886
https://bbs.a9vg.com/thread-5214563-1-1.html
KSS213-To-PS1-sch1.jpg
KSS213-To-PS1-sch2.jpg
KSS213-To-PS1-sch3.png
Also in the third link, there are interesting things about a listing on aliexpress (unavailable now) of a PS1 with an embedded KSS-213 assembly and a mod to solve the seek time issue I was talking earlier by using the original gear assembly. That's cool.
PS1-with-embedded-KSS-213.jpg
KSS-213-with-original-PS1-sled-gears.jpg
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Post by david4599 » May 25th, 2023, 9:22 am

alexfree wrote: January 13th, 2023, 9:58 am After using these drive for a bit, I have some more info I can share.
My SCPH-1000 still works really well with it. There is something really weird about picking up the wobble on the super old console models that have manual Bias and Gain however. Sometimes it just doesn't pick up the SCEI signal. This is not that big of a deal though because you only need to do this once when you boot or spin up a Japanese psx disc. It again reads the disc contents perfectly, just the actual wobble is iffy.

All my SCPH-1001s just can't pick up the wobble at all with the drive. No amount of bias and gain tweaking has made it work once on 2 different consoles of the same model.

My PSone SCPH-101 works with the drive every time to pick up the wobble.

So I think this should be considered. If you console has manual Bias and Gain adjustments these drives may not be able to pick up the wobble. The early PU7 at least can pick it up most of the time. My PU8s have never picked it up.

Any Console with auto bias and gain however will work every time to pick up the wobble.

If your console is chipped, picking up the wobble doesn't matter in this case. If you have a 1001 or any USA or PAL console that can be unlocked, it doesn't matter as well I'd you use a Cheat Cart to boot into i.e. tonyhax international rom or use something like freepsboot since the drive just becomes unlocked immediately anyways.
I got the same problem on my 5502. I was really intrigued about that so I hooked up my oscilloscope and compared the differences.
I figured out the pin 5 on the original drive's connector called NC (which would stands for "Not Connected") is actually used by some motherboard revisions as the signal that will be filtered to get the wobble data.
This is also confirmed by other people (pages 7 and 8):

https://bbs.a9vg.com/thread-5214563-7-1.html

From Google Translate:
"the No. 5 line of ps1 is a genuine signal line. If it is connected to the line on 213c, it can run without IC."
"My understanding is that if you connect the genuine signal, you can run the game without ic"

The term "ic" designate a modchip.

Here is what this signal looks like (blue = pin 5, pink = 22kHz filtered Tracking Error, yellow = demodulated SCEx):
KSM-440-osc-capture-1.png
KSM-440-osc-capture-2.png
KSM-440-osc-capture-3.png
By looking at the 5502 service manual, this pin 5 is connected directly to the "Push-Pull" potentiometer which allows to set the proper filter threshold for wobble detection (too low = weak 22kHz, too high = saturated 22Khz + "noise").

That means, if the motherboard has the "Push-Pull" adjustment (at least PU-8 (RV702), PU-18 (RV703), PU-20 (RV703)), the signal on pin 5 is needed and the wobble is not detected through the Tracking Error signal made by the RF amplifier (E and F photodiodes subtracted).
This explains why the wobble detection works on a SCPH-101 but not on a SCPH-1001.

I tried to hook up the Tracking Error signal (CL709 on the 5502) directly on the pin 5 but the wobble is not well detected that way. It is sometimes detected when the "Push-Pull" potentiometer is set to the max but this is not reliable at all.

By checking some random Sony CD RF amplifier datasheets, I saw that the CXA2581N has another signal I didn't know before called Center Error which actually creates a sort of Tracking Error signal but only from the 4 photodiodes A to D: CE = (B+C)-(A+D).
CXA2581N-Center-Error.png
I started to think that this could be the signal on pin 5.

To verify that, I made a simple version of that schematic to try to replicate the CE signal and see if the wobble can be found.
After some gain tuning by choosing proper resistance values, I could see the 22kHz signal of the wobble, my 5502 detected it well and the game launched successfully, no hesitation!
KSS-213C_To_PS1_v2.0-osc-capture-1.png
KSS-213C_To_PS1_v2.0-osc-capture-2.png
No need to adjust the Push-Pull potentiometer on the PS1 since we can adjust the Center Error gain.

As we can see, the signal is not the same as the original and not perfect. This is maybe due to the (common and low-cost) operational amplifier LM324 I am using that is not fast enough.
There are faster opamps but I only have the LM324 on hand.
Or maybe the KSM-440 has a modified Tracking Error/Center Error circuitry.

Here is the schematic on the modified converter board and what it looks like:
KSS-213C_To_PS1_v2.0.png
KSS-213C_To_PS1_v2.0-prototype.jpg
The best value for the potentiometer RV1 is around the middle (50k).

I can't confirm if it works properly on others board revisions than PU-18 but I am almost sure it will!
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Post by masterg0r0 » August 30th, 2023, 7:31 am

Does anybody know what connector ID is the power connector for the KSS-213C drive?

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