KMS 440 BAM Calibration

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Mr Rokobot
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PlayStation Model: SCPH-5502
Location: Japan

KMS 440 BAM Calibration

Post by Mr Rokobot » April 22nd, 2024, 8:25 am

Hello everyone!
Today I recovered a PS one but I noticed that the optical unit only reads burned games but not the original ones.
The excellent group is the KMS 440BAM.
How many ohms should I calibrate it to?
I read on the net that for a good reading it should not exceed 680 Ohms.
Could someone give me some tips?
Thank you very much.
Development Console: SCPH-7502 with MM3 Modchip, PAL Color Fix, PSxMemCard 512GB SD with FreePSXBoot, Action Replay with UniRom.
Development PC: Windows 98 SE, QDI P6V693A/A5/133E (Advance 5/133E) Motherboard, Pentium III 450 Mhz, 768MB SDRAM.

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PlayStation Model: SCPH-9001
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Post by Bluesfire » June 14th, 2024, 10:33 am

Hey there! I would personally advise against messing with the laser potentiometer for now.

More often than not, A PS1 failing or struggling to read discs just needs some basic maintenance and a recap. The laser unit should be cleaned, and it's rails freshly lubricated, followed by replacing all the electrolytic SMD capacitors on the console mainboard.

I struggled for a long time with PS1 repairs as a technician, seemed like no matter what I did I couldn't get most systems reading reliably. I had mastered cleaning and lubing the drives, I had tried new drives, even messing with the potentiometers. While sometimes you can get lucky and make a system read again by adjusting the potentiometer, it is a bandaid fix that only puts more strain on those failing capacitors. It will fail again.

Once I started recapping every PS1 I work on though? Completely different story. I now have a near 100% success rate getting PS1s to read discs reliably, including three personal units. It really makes all the difference. Not only on PS1, but on most early optical media devices. PS1, Gamecube, Dreamcast, etc all need recaps these days for continued reliability.

Hopefully this information helps!

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