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11Jan/194

B&O BeoVision MX 7000 RGB SCART

It all started by finding this beast on the footpath. I saw that it had two scart inputs and had to have it. I built an RGB cable for my MSX a long time back but have always been disappointed by its performance via a scart-to-HDMI converter. So, I set about testing and hooking it all up. Of course, it didn't have a remote, so I had to use an Arduino to translate another remote into the appropriate codes.

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With access to all the menus, I started toying with values, but the picture from the MSX was still broken!

What can be configured?

Via the front main menu? Nothing. Via the service menu? A lot more. With my model, I had to pull off the back case and short the service pin header (I'd actually really like to just install a pushbutton switch onto that!)

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Once off, and with the TV on TV mode, use something metal to short those two pins in the middle that say Service Mode. You'll then get the following message on the TV...

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Last error was a pf? Sure was... I just pulled the plug... total power failure! Here's the other error descriptions...

Code Description
No no error registered
PF Power Fail
00 till FF Error address on the I2C bus
DF Data failure (maybe EEPROM 6IC6 on the cpu board defect)
4E 1/38IC6 Tuner & IF port expander
84 1/38IC2 A2 Stereo decoder
40 31IC7 NICAM stereo decoder
42 41IC5 D/A converter for cut-off and drive
22 37IC2 Teletext decoder
8C 13IC2 Deflection controller
82 14IC1 Audio Controller
86 14IC9 Video Controller (14IC9 means Board 14 Chip IC9)

Anyway, using the arrow keys, you'll be able to configure the following settings. There's an awesome thread post here on BeoWorld from Die Bogener explaining all sorts of troubleshooting for the TV!

Code My Default Value Description
Rdr 50 Red drive
Gdr 45 Green drive
Rcu 28 Red cut off balance
Gcu 29 Green cut off balance
BRI 03 Brilliance Preset
COL 03 Color Preset
Hfq 37 Horizontal frequency
Hph 35 Horizontal phase
Ham 22 Horizontal amplitude
Vam 29 Vertical amplitude
Vsc 32 Vertical S-correction
Vsh 30 Vertical shift for centering
Vli 18 Vertical linearity
EWc 05 EastWest corner
EWp 1 EW parabola
EWt 41 EW tilt

With all these settings being adjusted (and then reverted) to no avail... I started to wonder if it wasn't a Japan vs. Australia thing... NTSC vs. PAL? Does the RGB signal have a 50hz/60hz rate or other 'remnants' from the units output? Is it Australia's fault for successfully implementing only one standard? (For once!)

Does RGB care about NTSC or PAL?

Wherever you read, you'll find hot debates over RGB and how the signal differs from a PAL or NTSC console. From what I understand, it's a NO. Any TV with SCART that is RGB capable will take an RGB signal from any device. Do correct me on this, thought!

Can My TV Decode NTSC?

Here's the service manual which points out the following difference between the PAL and PAL/SECAM versions...

pal-dec

Yeah, that's not just PAL/SECAM... it's PAL/SECAM/NTSC! But wait... the MSX works over Composite? Which has to be NTSC-J Composite? What gives?

Maybe it's my RGB Cable?

There's a good bit of information at this post regarding RGB cable issues and required voltages. Supposedly the SYNC signal on the SCART plug can just be fed Composite video, but it needs to be within tolerance. This also goes for the switching which declares what video format is expected on the SCART plug. So, after reading more on Sync for SCART , Sync Strippers and types of Sync from random consoles.. I ended up slightly more confused, but decided to rebuild my cable.

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Thankfully, my junk box had a beautiful SCART-to-SCART cable... I didn't know these existed, but it makes total sense that they do. It's wired as a 'crossover' as the output from one machine needs to be fed to the input from another. I'll never be outputting via a SCART plug, so I decided this hefty cable would shield me nicely from interference and provide a great base for a proper RGB cable for the MSX.

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With the SCART pinout in one hand and the Japanese MSX RGB pinout, I set out to rebuild the cable... I hooked up the minimal wires: R,G,B and Sync + all their required grounds. This got me nowhere. So I then hooked up Ys to the 'output select' and I received a mis-coloured picture!

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I quickly slapped spacebar... the fish are the screensaver for multemente on MSX...

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Oh right, I've swapped G and B around... wait... it's reading the RGB channels? But wait... if I then switch the TV to DVD... bang... wrong format!? Wait... this has worked all the time? I hadn't noticed the clearer picture... I'd just thought it was pulling composite over SCART... instead it was actually displaying the correct picture. For some reason, the TV is expecting a different format on V.Aux and that's where it's screwing up. RGB WORKS!

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It turns out that, if you have your SCART-connected device turned ON, then the TV tries to switch to its input, even if you've selected the wrong input? Seems to be a bug? Or a problem with my TV configuration? The TV was configured as follows...

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I set out to test: PS1 in AV1 and MSX in AV2. The PSX worked perfectly when the MSX was off and the TV was set to 'DVD' (which was the setting of AV1)...

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But as soon as I turned on both consoles, the MSX would trigger the AV1 channel to distort. Switching to V.AUX (or AV2, where the MSX was plugged in) worked! So, all this time... everything was working, I just didn't understand (still don't!) how the inputs work on the MX 7000. All I know is that you should only have one input powered up at one time! So, here's some RGB goodness...

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SCART cable quality!

This has all occurred because I saw the quality of the original SCART cable and thought it was composite! Here is the old cable plugged back in again. Note that it's just 8-core wire, no shielding... so the quality sorta makes sense...

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Compared to the shots above, you can see the distortion. But I admit, it's really hard to take a proper photo of a CRT! So.. it was nice to build a real cable.. although, dealing with the gauge of wire was a little tough. It seriously had a mind of its own!

Both units need an overhaul

Whilst doing all this research, I found notes on both items for overhauls! Seems that an urgent capacitor replacement should be carried out on any Japanese MSX with a specific daughterboard. Also, the BeoVision MX Service Guide indicates a whole bunch of capacitors that could be life-expired!

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  1. The issue where you get a picture which won’t sync could be due to that the scart input in question isn’t selected.

    The RGB switching usually happens separately to the video/sync input selection, so the TV might try to sync to the noise from the tuner while displaying the signal from the RGB input. The background for why SCART inputs usually work this way is that you can have some external device which syncs to the video signal that the SCART connector outputs and then feeds back RGB signal to superimpose text or graphics on top of the RF aerial signal recieved, for example adding teletext, subtitles or similar. This were never a thing, any such device could be considered super rare.

    If you have an Amiga and a genlock for an Amiga, you could connect the genlocks video output to video in on the SCART on the TV while connecting RGB from the Amiga to the SCART connector, and use the “zero detect” signal from the Amiga to drive the RGB switching input (of course via a series resistor). That way you’d get the Amigas video superinposet to whatever source you feed to the genlock, just as in a usual setup, but in this case with full RGB quality on the Amiga signal.

    • (part 2, as there seems to be a lenght limit for comments)

      It’s also common for a TV to only have a RGB input on one SCART connector. This could explain the issue with only one input working correctly.

      Also the incorrect colors might be due to the TV expecting a component signal rather than a RGB signal. It’s unusual to use SCART for component, but as it’s a 100Hz set, a component input seems reasonable.

      Also, as it’s a 100Hz set, you should try the interlace modes on an Amiga. With a bit of luck the 100Hz hardware will act as a flicker fixer.

    • Miam,

      Thank you for this extra information. It makes a lot of sense that the sync is heading back out the other SCART. The mismatched colours was my own mistake with soldering… and I am definitely not using component yet… but I do want to.

      I hadn’t realised this set was 100Hz! But it would make sense as to why the PS1 looks so damn good. The RGB for it is on its way.

      Meanwhile, no Amigas here… but I might just source one… if only for more crispy A-Train :)

      Again, thank you for the help!

      • Sorry, I don’t know where I got “100Hz” from – maybe I just interpolated that from something about state of the art of CRT TVs or similar :)


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