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jtcc1015 20th August 2007 08:41 AM

adjusting KHM-230AAA optical pick-up on Sony SCD-555ES
I have recently bought a used SCD-555ES and would like to perform some auto checks as described in the service manual in order to ascertain the status and perfromance of the optical pick-up. There is mention in the service manual that a test CD (PATD-012 or YEDS-18) will be required for the CD read test and a test SACD (SATD-S4) will be required for the SACD read test.

I will appreciate if anyone could advise me on how and where could I get these test discs.

On the optical pick-up assembly (KHM-230AAA), I found 2 pots. According to my friend, these pots are for the adjustment of the bias current to the respective laser diode. However, the service manual indicate that all operation parameters including Focus bias are automatically adjusted by the DSP, no manual adjustment is usually required. If this is the case, why these 2 potiometers exist, and what is the default position should they be set at?


catrafter 20th August 2007 02:43 PM

I'd leave the pots on the pickup alone.
I just use a clean single layer DVD (silver color), a clean dual layer DVD (gold color), a clean CD, and a clean Hybrid SACD for the indicated test discs. Run the test mode as indicated in the service manual, section 6.

Quote from service manual, p 59:

Note: This set automatically makes various adjustments according to the type of disc, thereby not requiring adjustment of the set when parts were replaced.


jtcc1015 21st August 2007 05:10 AM

Thanks Tom. I will try that out.

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