Portable buyers guide: which optical pickups are particularly problematic?

[bkafi]

I know that some of Sony's early optical pickups in some portables are particularly problematic, e.g. KMS-190A (MZ-R2). But do we have any reliable knowledge beyond hearsay which ones should clearly be avoided? And: Do we know what types of issues indicate a fully broken pickup?

 

I am asking because I just picked up an MZ-E50 and E3 for cheap and both are (expectedly) broken. The E50's (which apparently does not even have a service manual) sled moves in and out repeatedly before giving "Error" and the E3's KMS-201A lens package moves up and down a number of times before again checking out with an "Error". However, it does pass the focus test fine. In auto-adjustment mode, however, it hangs at "EF balance" test. I was not able to revive any of the two.

 

Are both blocks fully dead? Is any better identification of these issues possible? Should the E3 or E50 be avoided in the first place? How do I know if my block may be resurrected?

 

Thanks!

[sfbp]

EF Balance rings a bell in my memory. I would be very careful to check all mechanical movement is unrestricted (prime candidate is congealed/rubberised white silicone grease).

I'd also check continuity on the head but it sounds like you are way beyond that.

 

You might investigate what comes right before and right after the EF Balance check step, on a working unit.

 

Can you read a CD (pre-recorded/manufactured)? That is a prerequisite before any writing tests. Maybe you know much more about this than me.....

[bkafi]

Thanks, @sfbp. No, both devices do not even begin to read the discs. I forgot to mention that I do can spot the read laser when looking at the lenses in the dark. Unfortunately, I don't have good units to compare. I also have, of course, removed all grease and regressed everything in the beginning. 

 

I have noticed that, when everything's fine, the device should apparently immediately spin up the disc, begin and complete focus search right away and then start reading the disc. The E3 doesn't do that. It spins the disc but then goes "click-clack" moving the lens up and down six times before it gives an "Error". I suspected focus issues, but it passes the focus servo test fine. It does hang on "EF balance", but I am unsure what could be done to clear that up. Of course I fiddled with the FCBIAS and EF BALANCE settings in service mode, but that didn't change anything.

 

Without knowing what precisely an optical block is supposed to do on startup and in what order I don't think this is fixable. Would get a new one in working order, but I would only want to do this if I knew this type of KMS isn't prone to frequent failure.

Edited Wednesday at 05:42 PM by bkafi
Corrections