As most of us on the LDDB know, the stock Panasonic LX-900, while a superb player, has one serious defect - a video output amplifier that dynamically changes the APL (Average Picture Level) of dark areas of the image, raising them up into gray by anywhere from 7.5% to even as high as 20%. A few of the 900's do not have that problem at all, typically the later units made in 1994/95. The Runco LJR-I Super LaserDisc Player and The THX certified version, the Runco LJR-II Super LaserDisc Player, have a special board developed by MSB that fixes the problem and also ensures correct chroma levels, differential chroma phase and gain and units were all hand calibrated to ensure a correct 1-volt video output level.

What I'd like to do is have owners of LX-900's post the serial number of their player as well as its manufacture date - and also list, if they can tell, if their player has the APL problem and how severe it is on their unit. Also, any Runco owners please list their serial numbers and manufacture date - and if they've ever compared the player to the stock 900 and their impressions of differences, if any, in overall picture quality.

Me and another person may - we are still trying to decide if it's feasible - offer an upgrade for stock 900's with the APL problem that, like the MSB mod for Runco, would fix the error and basically make the player a pseudo-THX Certified unit, since our mod would exactly duplicate the circuit board that MSB used. Also, list what you'd be willing to pay for such an upgrade to your player or what you think it would be worth.

Having a listing of manufacture dates as well as knowing if the unit is affected by the APL problem would help us get a handle on how many units were defective and when Panasonic fixed the problem. It would also help us to know if there are enough players and willing owners to offer the modification.

Just list the info in this topic thread.

Your help would be greatly appreciated.

June 1995 and no APL problem that I can see. I'd still like one of these boards for those other adjustments though.

I never took down the S/N of the Runco that I owned. I have a pic of the rear of the player, but the S/N isn't really readable:



I'll get the S/N of the LX-900 that I currently have. As of yet, I haven't noticed any auto adjust with any movies I've watched.

What would you pay, or what do you think would be a fair price?

BTW, have you found a knob that will work with the front panel jog dial post and have you found a LX-900 remote, since it has functions, like black & white mode (which is so nice for old films), that are not on any other remote. If you want, I can program the 900's remote into a cheap programmable. That would be cheaper than buying a 900 programmable replacement.

I could probably be talked into selling or trading the jog and shuttle dial from my other 900 that exists for me only as a parts player, even though it works perfectly. It's just too bad the remote is broken and prolly can't be repaired.

You won't see it dynamically adjusting black levels - they'll just be gray, of various lightness, instead of true blacks and darker grays. Dark films, like Batman, show it off well - the image can also look like there isn't enough 'room' between dark and true white levels. It's kinda odd.

If you wanted to do the mod, what would it be worth$$ to you?

Oh, do you feel the Runco's image was better than the 900's?

The Runco's wasn't better than the 900's but, as evidenced by that video I showed you of the Runco with the Snell & Wilcox pattern (as this was the Runco I used for that video), it wasn't really a fair comparison.

The lowest amount I can get away with.

I've been using the LX-600 knob, but it has no jog (I forget which is jog and which is shuttle some times...) and it would be nice to have a real LX-900 knob. The 600 remote works on the 900, but is missing the 900 exclusive functions, and Logitech doesn't have them either, so it would be nice to get a remote for that, I'll send you a pm.

it all depends on what the upgrade is, if it's something like an AC-3 add on i would say around
that cost, if it's something harder to do then more.

but it all will depend on hours and parts and how many really want to do the upgrade.

So my 900 is from January 1995. No APL problem that I've been able to see thankfully.

I'd really have to see the problem in action to determine if I'd want to pay to have it modded.

My LX-900 is from May 1995. I've never seen any evidence of the AGC problem and I consider myself ridiculously picky when it comes to video issues.

The best test I could think of for this was on the video essentials disc where you have the pluge test pattern for brightness followed one frame later with the same black bars on a bright background. With an aggressive AGC circuit your brightness settings would have to be set significantly different between the two right?

I know the type of display and its quality play a factor, so I compared the relative difference in brightness levels using my video essentials DVD and there was no significant difference.

Does what I just wrote make sense?

BTW, there is a denon la-3500 remote on eBay cheap right now. This is virtually identical to the lx-900 remote if anyone needs one.
http://item.mobileweb.ebay.com/viewitem ... 7529123308

Sad to say they don't use the same IR codes - Denon used their own remote coding system for their version of the player - heck, they even allow the user to adjust the VNR from the remote. I have one of the Denon LA-3500 remotes and they don't work with the 900, nor can they be made to - they have different IC's in them.

Did you find out whether there was a switch or jumper setting inside the player to recognize the Denon instead of the Panasonic control?

Thanks, now Im stuck with the Remote as I just paid for it

Panasonic seems to have fixed the APL problem towards the end of the 900's retail life, which was in 1995 - I have one from late 1994 and it doesn't have the APL error, but my 93 model does, as do those made in 1992.

The MSB board, in addition to fixing the APL problem, allowed calibration of differential chroma gain and phase so that colors were reproduced correctly in hue and level at all times and also a frequency response adjustment to flatten out the video response - the 900 has no internal adjustments for any of that, thus an add on board for adjustments. Except for AC-3 RF out and a different front panel, there were no changes or additions to the circuits of the LJR I to make the THX Certified LJR II. Runco stated that several times in different magazines and guaranteed that the performance of the I and II were identical.

No jumpers or switches - the remote has a totally different code system.

Oh, bummer. The Denon remote is totally useless with the 900.

With a service manual, it ought to be possible to locate the remote decoder in the player. If it's a multi-system chip, as is often the case, & the data sheet can be found, it might be possible to do a mod ; actually, replacing the decoder IC is not impossible, but it might be easier to replace the encoder IC in the remote.

I apologize for steering you toward the demon remote. Since the la-3500 was based on the lx-900 and the remotes look the same I figured it would work.

Well, now you're in the same boat that I am . . . trying to find a Denon LA-3500! Of course, I'm just trying to find one for the helluvit.

Along the same note, I'm sure a few of us have checked out Joshua Zyber's "Laserdisc Forever" website at one time or another. In the "Ask the Laser Guru" section he mentions in describing LD-G to a reader that an American released Denon LD player had LD-G decoding functions built-in. Does anyone know which model he's talking about? Is it the LA-3500?