GEX : almost horrible!

[GEX : almost horrible!]

I love these stories from the Golden Age of console games. I liked the dark early fmv themes of mid 90's games like Gex. Have u seen Burger Becky's YouTube blog of her involvement with porting Doom to 3DO

really interesting watch.

[Looking for 3do]

I would say they are both just as easy/hard to mod as each other. Depends on the mod u are trying to do.

[3DO reading burned games]

Glad you got it sorted. That's interesting that you got better results burning the discs at the imgburn recommended speed. From what I've seen the 3DO laser pickup is among the most temperamental.

 

 

Here is a comparison of RF signals from CD lasers using an oscilloscope. It's taken from this page http://www.activewin.com/reviews/hardware/burners/yamaha/crw70/technology.shtml which has some more info on jitter. It's mainly about burner quality but the principal is essentially the same. The quality of the burner, the media and the laser pickup will have an effect on the amount on jitter present in the signal. The more jitter, the harder it is for the CD-rom to maintain a stable read. All CD-rom have error correction but with a high level of jitter, it's more likely the CD-rom will be unable to recover from a bad read and the console will throw off dirty disc errors.

 

By minimising the jitter as much as possible, we can enjoy stress free gaming.

[3DO reading burned games]

Write speed should have no influence on the readability of the disc. The info is still stored in the same place. The 3 factors are the quality of the burner, the quality of the disc and the quality of the optical pickup.

 

The 3DO pickup is notoriously picky about which brand media it will read. Always use best quality media like Taiyo Yuden. Also make sure the laser is cleaned with isopropyl alcohol.

 

Your laser may be getting weaker but start with the first 2 suggestions. If it still has trouble reading discs the the laser will need adjusting or replacing. Both are not straight forward. Replacement lasers are practically non existent and similar lasers require a bit of modding. Adjusting the laser power requires an oscilloscope.

[New 3DO RGB Mod Possibility.]

That's cool that u are making progress on this. I may have been off with my original statement of 56us. I was looking at this page http://www.sega-16.com/forum/showthread.php?25988-RGB-LEFT-RIGHT-sift-issues-theory-and-fixes

And mistook 8pixel for 8us. So the shift needs to be more like 62us.

 

My 3DO is out of action at the moment as I tried to swap the encoder for a BT9107 but it didn't work :-(

 

I think if I revisit my RGB mod design, I would make it similar to yours with horizontal correction and TTL selection.

[Definitive guide to burning 3DO games?]

All 3DO play burned backups. The copyright protection was never added in the design, same as Sega CD, probably because nobody owned personal CD burners in 1993. The problem is probably the memorex cd-r. 3DO were always picky about the mods they read. U need to get some Taiyo yuden or equivalent quality cd-r. Also the laser could be getting weaker. And yes, slow load times were due to the 1x cd-rom.

[New 3DO RGB Mod Possibility.]

It looks like the VP536 and BT9103 just get CLK and 24bit RGB from the mobo/ CLIO, the rest of the timing is managed by the encoder. Both encoders receive 2 clks and create either 240p or 480i (288p or 576i for PAL) depending on the progressive pin state. The only way to get RGB on these consoles is to insert a new RGB capable encoder and feed the necessary signals to it.

 

The problem with horizontal shift is the Hsync is being delayed relative to the processed RGB. the pipeline delay within the encoders is minimal but in the Sync stripper or XOR chip it is more so the 2 parts of the signal are out of time. Maybe just using Luma as sync would eliminate the delay but it is undesirable.

 

As we can't speed up the Hsync, we need to delay it by a complete cycle (64us). As the horizontal shift is about 8us delayed, we need to delay by about a further 56us.

 

With the BT encoders, there are 2 further possible solutions. The BT9101 outputs CSYNC natively so this could be used as is with a 480 Ohm resistor to attenuate the TTL signal.

 

The BT9103 has the same pinout as the BT9107 which is RGB capable so these could be swapped out on the mobo giving native RGB. I still need to test this one.

[New 3DO RGB Mod Possibility.]

Here's some info on termination types https://www.diodes.com/assets/App-Note-Files/AB023.pdf

 

And from your favourite company http://www.ti.com/lit/an/snla034b/snla034b.pdf

 

Each method has its advantages and disadvantages. Older consoles such as Sega MD, Ps2 and possibly 3DO use series termination, while Sega DC uses parallel termination.

 

Yes I was thinking a specific 'U' or 'L' shaped QSB with a 28 pin ffc connector for each encoder, connected to a generic main board. 24 bit RGB, CLK, SYNC, 5V and GND could be acquired directly from the native encoder, or power separately, and fed to the main ADV7125 board via ribbon cable.

 

Good luck with your new revision.

[New 3DO RGB Mod Possibility.]

Good idea. I was starting to lean towards quick solder options with my design as well. Either with pin headers or QSBs. A different design would be needed for each encoder but it would make installation a lot easier. This is not possible with the BT9101 encoder as it is a fine pitch 160 pin QFP.

 

I made a mistake with my design by including a parrellel termination resistor AND a series termination resistor. Only one is needed, my design was effectively triple terminating the signals, oops. Analogue Devices use parrelel terminating resistors in their designs while the online community advocate series resistors.

 

It is advisable to place the 470ohm resistor close to the console end as possible but as you said, the AC coupling caps (220u - 1000u) can go either end on the line.

 

This page has some good info on reducing parasitic capacitance in video signal lines https://shmups.system11.org/viewtopic.php?f=6&t=55948

[New 3DO RGB Mod Possibility.]

Nice work. Looking forward to seeing your final design.

 

I completely forgot about TTL sync voltages. Definitely need to add a 330-470 Ohm resistor in series to the csync line output. If not then the 3.3v decoder in the video display will get eventually damaged from the 5V sync. The only reason to have a switch to keep TTL levels would be for VGA displays. Did u manage to test RGBHV on a vga display?

 

I know what u mean about 0402 packages. Ugh! Never again. I stick with 0603 for chip resistors and chip caps. I use 1206 for led and 1206/1411 for tantalum caps.

 

I will try to put together a tutorial for installing RGB on the BT9101 and BT9103 encoders when I've finished testing.

 

Looks like blanking isn't required for newer TVs. May still be required for older CRTs.

[3do and composite and svideo]

It depends on the quality of the upscaler in the tv. RGB is sharper and more vibrant than Y/C but it will still be at 240p/480i. I will be installing my new RGB mod as soon as the parts arrive so I will be able to get a better idea after that. I've got an older SD crt and a newer HD LED so I will be able to get a good comparison. I will let u know :-)

 

As I said, for retro consoles, I recommend RGB + XRGB/ OSSC on a HD tv or RGB + CRT/ BVM monitor.

 

Edit: also check out this thread for discussion on 3DO + Tv type http://atariage.com/forums/topic/153978-3do-lcd-or-tube/

[New 3DO RGB Mod Possibility.]

I've been there myself. I managed to get the rows mixed up on a xbox360 DVD power adapter I designed for flashing Xbox DVD drives. Had to reverse the wires on the power cable to compensate.

 

If the SMD lands on your pcb are suitable for 2 of the SOT-23 diode leads then u should be able to get away with it for this batch of test boards as the 3rd pin is NC like you said. It's all part of the R&D journey

 

This design will work with all 3DO as it takes 24bit RGB from the board and strips SYNC from Luma. It bypasses the native encoder. The pinout for the other encoders can be found in this thread

https://assemblergames.com/threads/240p-output-on-3do-with-bt9103-encoder.66295/

[New 3DO RGB Mod Possibility.]

LOVE the progress you guys have made here! Well done! I'm beyond stoked to see this inch closer and closer to becoming a reality. I'd love to replace my Otaku board with a better solution and will definitely be in for one of these once you guys are finished up.

Full credit goes to @The_Crayon_King for this one. I've just chimed in with a few observations.

 

Quick work on the design change, very nice. These will definitely work, it's just a matter of testing now. With all the research so far, these should work across all 3DO and also some Philips CDi models. The good thing about the ADV7125 is it's high end so it will give stable standardised RGB outputs. Just stick to the recommended Vset and Rset values. With the BU3616K, there is not a lot of info in the data sheet and Rset was valued too high which was evident in the reports by other modders who found the picture very dark. I've had to work out Rset from what little information was given.

 

Regarding 5V, I recommend getting it from an analogue 5V source close to or from the VA536. The 7805 is a digital source and will be 'dirtier' than the very clean analogue 5V that the VA536 will use.

 

If you want someone to test your design on the BT9103 encoder then let me know, I would be more then happy.

[3DO RGB Mod - - unavailable?]

The board looks like his own idea. It uses a BU3616K chip which is popular amongst modders for doing their own 3DO RGB mods. It's cheap and simple. Not sure why he extended the board out from under the CD rom, he could have kept the chip directly over the original encoder and saved pcb space. This design is great for VA536 encoders as it piggy backs onto the chip.

[New 3DO RGB Mod Possibility.]

Thank you for your comments. I realised I had placed C5 and C6 were too close to the IC, if I keep them in the final design, I will move them to a better position. They are extra power decoupling caps so they may not be needed. If I do move the filter caps and resistors back to the pcb, I will use your design as it's the best layout. That's interesting using the MD-80SV. I was going to use a C shape 8 pin din panel mount as these are the easiest to acquire. The only issue was finding good quality SCART cables with a 8 pin din connector for a good price.

 

I plan to release my design as open source for people to use as an alternative to the old DAC ladder design. I would of course give credit to your design as it has been very informative and helpful in my own research. I originally reviewed 6 different 8bit triple dacs and found the ADV7125 and BU3616K to be the best choices, with the ADV7125 being more high end. I have potentially deciphered the other 3DO encoders so your design should be fine to work across all 3DO https://assemblergames.com/threads/240p-output-on-3do-with-bt9103-encoder.66295/

 

I look forward to seeing how well your design works. :-)

[New 3DO RGB Mod Possibility.]

Looks good. Here's my BU3616K design

 

 

I have left out the 75Ohm + 220uf from the circuit to keep it smaller and cheaper. I was going to put them in the SCART socket but I may add them back to the pcb after seeing your design. I have also wired CLK and SYNC away from the RGB to avoid interference. I have kept the LM1881 circuit simple with just a 0.1uf cap and 75 Ohm termination resistor on Sync in. The LM1881 circuit that you have used is the full circuit but I haven't heard of any sync issues so I have kept it smaller and cheaper. This is just a proto design and I will probably modify it after testing and troubleshooting.

[New 3DO RGB Mod Possibility.]

I have a PDF of the pinouts for the VPA536, blanking and sync is mixed internally. The only output being H/V sync. Blanking being applied to Luma and Composite out. That's why I was thinking of stripping blanking from there. But the back porch should suffice.

 

The VA536 produces its own Blank signal but the other 3DO encoders get it from the CLIO chip. My theory was that as long as the pinout of the CLIO was unchanged and the Blank signal was still produced (though not required), you could wire Blank from the CLIO. But it looks like you have solved that problem anyway :-)

 

I had the same thought About HV sync with my design. I've kept pins for both CSYNC and Vsync so I could test VGA compatibility. But I think most modern PC monitors only accept 480p signals and above. Older monitors accept 240p I think.

 

I had to edit Eagle foot prints as the BU3616k wasn't listed. Assigning all 48 pins was a ball ache. Good luck with your prototype, very interested to see how it turns out.

[New 3DO RGB Mod Possibility.]

Glad you are making progress with this :-) Yeah I'm not sure about Blank either. Like you said, the timing could be off by using the Back Porch signal. I've noticed that the BT9101 and BT9103 both use Blank signal. I will try and trace my BT903 Blank pin to the CLIO chip. Hopefully the same pin on VA536 motherboards will provide an active Blank signal.

 

Do you have a picture of the RGB mod chip you found? It sounds like they might have used a BU3616K chip which is about the same size as the ADV1725 but simpler in design and application.

[3DO RGB Mod - - unavailable?]

All 3DO are RGB able. The video encoders in the 3DO are unable to output RGB so another circuit is added to convert the 24bit digital RGB to analogue RGB. The old method used 3 DAC chips and another IC to produce a sync signal. Because of this the board was quite big.

 

It would be interesting to know what this French shop is using, whether it's just another Otaku board or a newer smaller IC.

 

The problem is whatever the circuit, it will always require soldering 24 digital RGB wires to the motherboard so people without experience will need to rely on modders and shops to install RGB on their 3DO.

[3do and composite and svideo]

It's the TV. Modern LCD/LED TVs have bad results with 240p/480i video feeds. They are designed to display 720/1080p so they have to upscale lower resolutions. The upscalers in the TVs aren't great at this. That is why people invest a lot of money in upscalers like the XRGB/ frameister or OSSC.

 

On a CRT, the difference is more noticeable between Composite and S-video. The best option for picture on a HD TVs is RGB --> upscalers (XRGB/ OSSC).

[WTB or WTT: 3DO FZ-10 Game Console (have consoles for trade)]

Glad you have got a working console. I know what u mean, sometimes it's nice to take a break from fixing things and just play.

 

Let us know if you do manage to fix the other one. Happy gaming.

[3DO Repair Help :)]

Hmm. Maybe the laser is actually on its way out after all. I would have also checked a Japanese specific game before removing the ROM2 to confirm it being the Kanji chip. Keep that ROM safe incase u do want to play jananese only games in the future.

 

Edit: Fantastic! Glad it's finally working. Wonder why that game worked but the others failed?

[3DO Repair Help :)]

Thanks. That's very interesting. Your FZ-1 motherboard has 2 ROM chips. ROM 1 is the Bios (IC341) and ROM 2 (IC340) is usually blank on US and PAL consoles as it's usually where the Kanji chip goes for the Japanese games which have Kanji fonts.

 

Which games did u test on the console? Some US games wouldn't play on a Japanese consoles with the Kanji chip.

 

http://3do.cdinteractive.co.uk/viewtopic.php?f=25&t=3739

 

This thread shows how a guy was able to remove the Kanji bios to allow the console to boot US games. Possibly something to look at in the future if u want to get this console booting games again.

[3DO Repair Help :)]

That's a good find. Just swap the CD drives and you should be good to go.

 

If u get a chance, could u post a picture of the Bios chip? It would be interesting to see if it's a different IC to the stock IC or just flashed with a custom Bios Rom.

[3DO Repair Help :)]

That's great that u solved it. do u know which game it's programmed to work with? Can u post a picture of the bios chip?

 

This may explain why other people get this issue rather than the asteroid screen. I've read about people swapping bios and adding kanji bios, maybe this can be done with your motherboard to give u full access to the games library.

 

Glad u got it figured out.