Does that go for any of Denon's OEM'd LD players? The LA-2300 and 3300 are based off of the Pioneer CLD-D604, aren't they? So I take it the remotes for the Pioneer player won't work for the Denon model and vice versa?

The full schematic of the 900 is available in the PDF manuals section here on the forum - you should give it a look and see if you notice anything that might be helpful.

One interesting note is that the Denon version of the 900 also was afflicted with the APL error. And Denon gave their player full CD-G and LD-G decoding - I don't think Panasonic's Japanese version of the 900 had LD-G, although it did have beautiful polished wood side panels much like Pioneer's Elite gear - its weird Panasonic didn't keep that feature for the US version. Denon didn't use Panasonic's wonderful low-bit Super MASH DA converter chip though - they used their own DA conversion system that processes low level digital signals to make undithered sine waves look good on a scope, which is useless in reality since, except for test CD's, all digital recordings are dithered in some way, either specifically by the engineer or by tape or mic preamp noise in the original recording.

The 900 was also sold under the Quasar name as the model LD700, and I don't know if it had the APL problem - or when it was introduced at retail. If it was towards the end of Panasonic's production of players, it might be free of the error.

BTW, the Quasar jog/dial remote IS compatible with the 900/Runco/MSB players.

Denon used OEM Pioneer players for many of their models, but I don't know if they changed the IR codes or not.

Yep, the LA-3500 has LD/CD-G capability. A real rarity for a US released player. I've been looking for a 3500 also just because it's cool looking and has the Graphics capability. I have a lot of CD-G's from the early 90's when the format was launched and before it became used for Karaoke. Warner produced a cool CD-G demo disc that they gave away with the first CD-I players and TurboGrafix CD units and it really shows how neat the format could be. It's a shame it never became popular.

The Runco LJR I DA should arrive tomorrow and I can't wait to put it through its paces - although I'm going to have to save up $ to have Duncan add AC-3 RF out. I'm glad I have 2 LX-900's to act as parts supply if the Runco needs repair.

Runco sent me their last copy of the brochure for the LJR II, as well as the instruction manuals for both the LJR I & II, but I've not been able to find a brochure for the LJR I yet. Does anyone on the forum have a copy?

That's cool that the LA-3500 has LD-G built in. Makes me want one more now!

I do have several devices that are CD+G compatible; Turbo Duo, Sega Saturn, Pioneer CLD-V880, Skyworth 1050D Prog Scan DVD Player (all region.)

Of course the only software I have for them are karaoke CDs.

Speaking of the LA-3500, I have the full service manual for it if anyone has technical questions about it. I just haven't had the time to scan it and add it to the manuals database. I bought it hoping it would be useful for the LX-900, but later tracked down the actual LX-900 schematics.

The mechanics are very similar to the LX-900 but they completely changed up the circuit board layouts. The actual circuitry (aside from the LD+G and the audio DAC section) is pretty much the same from my cursory look at the schematics for both players.

Perhaps I (or someone more knowledgeable) could find something useful about the remote?

Just throwing it out there, but if anyone is desperate for an LX-900 remote, but has a programmable universal remote. You could send it to me and I can program in the functions.

That's what I'm doing for Naiaru - or just giving him my semi-functional 900 remote since the buttons that control 900 specific functions, like Retro mode (which I love for playing B/W discs) work fine.

If you could scan the service manual for the Denon, I'd be really greatful to have a copy of the whole thing.

My original Philips 910 CD-I player died, but I have one of the top loading Magnavox players that came with the MPEG-1 cartridge built in, so I can still play my CD-G discs like Chris Isaak and 10,000 Maniacs. Plus the incredible CD-I disc about the Titanic - its still the best source of info on the ship and disaster. I have about 150 CD-I titles - I really liked the format - Palm Spring Open Golf is a game we still play all the time, as is Battleship. In Japan, Goldstar came out with an LD player with CD-I built in. The CD-I format could have easily been stored on the digital tracks of LaserDisc's to make incredible interactive titles. Pioneer kinda tried it using NEC and Sega with their half-assed LaserActive system, but CD-I was a world standard and would have been better suited to creating special edition LaserDisc's of movies and such with all kinds of extra info.

That would be helpful. If we can figure out whether the LA-3500 has the same remote decoder chip as the LX-900, we can figure out whether or how to make the players & remotes interoperable. At a minimum, if there is a schematic for the remote, it may be possible to work out how to make the modification there.

OK, a check of the LX-900 schematic shows that the remote control signal goes directly to Pin 23 on IC001, the microcomputer which also accepts key-presses from the front panel & drives the fluorescent display. The part number listed is MN187324VTRX ; a data-sheet check shows MN187324 as an obsolete part, substitute is MN101C07A ; data-sheet check shows that this is a general-purpose 8-bit microcontroller with 32 KB ROM. Almost certainly the "VTRX" suffix indicates that the ROM is loaded with a specific instruction set for running the LD player. It stands to reason that the DENON simply has slightly different contents in the ROM, including a different set of remote codes. This means that there is no easy fix on the player side.

Unfortunately, the schematic provided doesn't include the remote control unit. It looks like a substitute encoder chip might be the thing to use — it wouldn't be too difficult, I think, to program a microcontroller to handle both sets of codes, & have a switch to select between them. But by that time you could have gotten the correct remote!

Publius, i have a question for you that's unrelated to the remote issue - the Hi-Vision LaserDisc player you own is the Sony/Panasonic version, correct? Do you know what kind of comb filter it uses? I was just wondering if the non-Pioneer Hi-Vision players utilized 3D adaptive comb filters for LaserDisc playback or just advanced 2D adaptive. Do you have a service manual that lists the IC used for the comb filter? Also, since Panasonic developed a sophisticated 2 IC digital processing system for LaserDisc that was used in the LX-900 I wonder if Panasonic used that chip set for standard LaserDisc playback in the Hi-Vision player? Panasonic didn't use the digital IC's in any players not based on the 900 - all lesser players used just the first chip that did the basic demodulation, DOC, etc... The 2nd IC, that did the more advanced processing such as composite 3D DVNR, 2mbyte digital TBC & Velocity Error Compensation, mixed-modulation noise removal and CLV FX, was never used in lesser players. Unlike Pioneer's 3D DVNR system for LD, in the 900 Panasonic applied 3D NR and all processing to the video signal while it was still in composite form and the signal only went to the 3-line logical comb filter after everything else was done - and again unlike Pioneer, the DVNR stays operational during CLV still frames and FX.

By any chance, while looking at the schematic did you notice anything weird in the design that would cause the APL problem?

Now, this is an interesting question. The LX-900 appears to use a pair of chips, MN8811 listed as "Digital TBC/Noise Canceller" & N8812M "Fain [fine?] Noise Reducer & YNC". (The schematic I am looking at has a good deal of Chinese text as well as attempts at technical English, so there is a fair bit of incomprehensibility.)
The HIL-C2EX, also marketed by Panasonic as the LX-HD20, has a different video processing chain. The principal components are : IC503, "Video signal processor/demodulator, noise canceller, video amp" CXA8020AQ ; IC504 "NTSC TBC" MN8811 (same as in the LX-900) ; IC716 "NTSC digital comb filter" CXD2029Q ; and IC832 "NTSC chroma digital noise reducer D/A converter" M65631FP. The audio DAC, by the way, is CXD2562Q, preceded by a digital filter CXD8504. Unfortunately, all these parts seem to be very difficult to track down!
The signal flow diagram is also rather maddening — parts of IC503, in particular, are used for different functions, so that the video loops through it several times on its way to or from other components. I'd have to give it a good deal more study to be sure of what was going on. One thing that is clear, however, is that the "direct" BNC output is quite separate from the other output connectors, not even being attached to same circuit board. It appears that, when necessary to insert text, the direct output signal is actually suppressed, & the signal present at the "regular" composite terminals is substituted.

The Denon service manual shows a variation of the same chip is used in the LA-3500. The part number is MN187324GD. Unfortunately the manual doesn't have a schematic of the remote.

I own an LX-900 manufactured in October 1992, with serial number DA2540101.

I have never noticed the APL problem. I probably need to see the problem, or a better description of what the symptoms are to know if my player has it or not.

The APL error causes grayscale levels to be reproduced incorrectly. On the 900 it affects the lower levels, so dark or black areas end up being much lighter than they should be. And since color depends on the grayscale being displayed correctly, it can cause colors to be reproduced with the wrong depth or shading. Depending on the disc it can make the picture look washed out or pastel looking. If your set has a dynamic contrast or auto black level control that's on or non-defeatable (most CRT sets had non-defeatable auto black level) you probably won't notice the problem because the set pulls down the incorrect levels, somewhat correcting for it. Or you may just be used to the image the way it is - and the 900, even with the problem, produces an excellent image, but on bright, daylight scenes it doesn't cause much of a problem, althoigh dark films can look very bad - Kurtis uses Batman as an excellent example, since it has so much black and gray in it. If you compared a 900 with the APL problem to one without, the one without (on a good disc) will have a balanced, dynamic look to the image, with much more detail in darker areas, which gives the image more depth and realism.

I hope I answered that well enough - Pioneer's first player, the VP-1000, had major differential chroma gain and differential chroma phase errors (as well as a 38db chroma S/N ratio), meaning the saturation and hue of colors would change depending on the scenes brightness. The LD-1100 corrected that somewhat, but not fully, so for years I thought that's just how LaserDisc's looked - then I got a CLD-1010 in 1987 and won a Philips CDV-488 (which was even better than the 1010 in color quality) in 1989 and was shocked at how much better all my discs looked. So it might take some side-by-side viewing to see the difference. One of my LX-900's doesn't have the APL error and it's picture is wonderful, but next to the Runco LJR I, it doesn't look nearly as good since the fixes applied by MSB to the Runco did more than just correct the APL error.

My Runco's serial number is 730133 - I need to get behind the video cabinets and get my two 900's serial numbers to post.

I have both an LX-900 (1995) and an LD-S2 (1992) and haven't been able to see a difference in black level between the two. The ld-s2 has significantly more chroma bleeding however, which gives it a softer looking picture.

If the 900U output level problem was fixed in later models it should be easy enough to see what was done. Either by comparing schematics or two actual players.

Can anyone with a new or an old player post some high resolution photos of the boards. Maybe we can work out what was done.

Is there a newer schematic for the 900U. I would think there would have been a service bulletin.

I think it's in the digital IC's since the 900 is mostly digital, unlike the Pioneer models. So some later programming change maybe fixed it - before that, MSB came up with their own way of doing it - the MSB board is very complex with many square IC's with lots of connections. Some parts of the board are labeled like, servo amp, video line driver, high speed video Y/C Mix, and the board connects directly to the composite and S-video outs. About 10 wires go from various IC's and such on the Panasonic boards to the MSB board. I took pictures of the entire board, but they are not very clear - when my partner gets home I'll take better ones with his macro lens camera.

Here's a (bad) pic of the whole board- the bottom is the front of the player.


Here's a close up of the front of the MSB board


Here is the back of the board - you can see the connections to the composite BNC connectors at the bottom. The Y/C mixer is to the right under the metal frame.


So, as you can see, MSB did some major mods - and there are also the audio mods underneath the player potted in the EMA isolation plate the player is built on. And there is a 2nd transformer for the audio mounted just above the main transformer. And major parts are treated with 3M's EAR Isodamp to absorb vibration.

Thanks for the pictures, using the flash would probably let us read the chip numbers etc. I'd be really interested to see where the board connects to the standard board, it would give us some ideas for picking up the signal.

Re the standard 900U, If they changed one of the digital ICs in the later 900U models then I would expect a revision number on the chip (like an A or a B onthe end of the number for example).
It could be that they just bypassed the AGC.

A high res photo of an older and newer model should tell the story.