SEGA Mega Drive - Jailbar Fix - Model 1 (PAL VA4) Triple Bypass

[@3vi1J]

Glad you paused and zoomed in - I wasn't seeing them at first. The compression makes the jailbars less visible during the moving fullscreen images, even at 1080p. Then again, my old eyes have their own graphical artifacts nowadays. :)

[@mickabajerski4985]

MY MAN, DAYBREAK FROM ALPHA 3, Emotion mode on

[@GameTechRefuge]

Great soundtrack. Alpha 2 & 3 are awesome.

[@Four_X]

Wow the video from the Mega Drive look great Dermot. Think I'll fit one in my spare Mega Drive's.

[@GodKitty677]

I have a stock PAL VA4 that has no jailbars and audio with zero noise. I got all the mods as well, yet to install them. Notes: Pin 21 goes to the positive pin of c41, dont solder on the pin ever unless you have too which you dont. Also never run the wires close to the motherboard as that puts them closer to the noise but looks nice I guess. No one is looking inside, let the wries do their thing, so long as its away from the motherboard. The RAM in this video is what you are avoiding, noise central. There is no need to pull up any pins on the VDP, at all. You will just break the pins, as they are weak. You can remove the resistors on the other side. This will keep the 5.6K ohm pullup resistors in the circuit and thus you wont have to replace them. You can still buy the 315-5313A-01 or get a cheap mega drive and replace it if the pins break. Its just costly. They cost £6 each, or £4 for more than 3 but its the postage that is a killer. If you buy the right equipment this is far easier. Working out how to connect this on your own is not easy. This video really helped me, I had worked out the method to install I was going to use and this video help me feel confident to go ahead and try it. I used a different install method, I traced the RGB traces and disconnected them by removing resistors on the back of the PCB. This way you are not driving two outputs and this will darken the output. I was able to leave the csync circuit alone with out it causing any issues. The two resistors for that are left intact. There are caps that go to the pins on the IC (not the VDP) I left them on the PCB as well. There are caps for RGB and csync. Good luck with your project. With hot air this is far easier and you can roll back the mod if needed. I got a broken Mega Drive with a missing VDP pin 27 Red. In the end using a dremel to expose the pin didnt seem like an end result I could sell. So I replaced the VDP with one from a second mega drive. Your console can survive a lot. So long as you don't damage traces and pads. So long as that one custom Sega chip is undamaged. In this video we see a VA4 motherboard. Be sure to do the Sega fixes, these stop flicking and crashing.

[@emmettturner9452]

Where can you buy a new VDP? That is good advice regarding the wire routing and RAM interference. Flying wires that avoid the RAM are best! Unfortunately the RAM traces run right beside the RGB traces so I prefer to lid the legs. On some boards the CSync trace runs along RAM traces too and could bring video interference if routed together, just like using unshielded composite video for sync in an RGB cable.

[@davethebulb]

Instead of lifting the RGB pins I simply removed the 3x 5.6k pull-up resistors from the underside of the board and soldered to the pads, thus removing the original DIN form circuit. I then added 3x 5.6k resistors to the 3BP V2 board between 5V and RGB out.

[@GameTechRefuge]

I considered it. I went with the through holes and *perf board, so if someone in the future, removes the bypass the old pull ups will still be there.

[@davethebulb]

@@GameTechRefuge Did you perform the 5.6K pull-up fix after lifting the pins though to sort the colour gradient issue?

[@GodKitty677]

@@davethebulb I disconnected the resistors at the back of the board and leaved the pullup resistors in the circuit. That way you dont need to cut traces or lift pins. Just solder to the vias. This makes the install cleaner and you can roll back if needed. You also dont need to add any pullup resistors yourself.

[@davieslm]

Excellent video! Just managed to pick up mint Japanese Model 1 (first run) Mega Drive. It came with a cheap generic scart lead and when I hooked it up to an LCD it had strong vertical lines evenly spaced throughout the entire image from left edge to right edge. I was hoping that these were just 240p /480i scaling issues. When connected to my Pioneer plasma over composite you can see the more typical light jailbars that are spread out. I don’t yet possess the same great soldering skills as you and don’t wish to damage my prized example so I need to practice on something else :) Therefore just ordered a quality packapunch RGB cable, RAD2x along with a CRT. Hopefully this will have a huge improvement and maybe I can live with some faint jailbars. I will see. Anyway great channel and just subbed!

[@GameTechRefuge]

I had one of those but decided not to mod it. They're just so cool. They have a little daughter board with the main clock crystal on it, as they discovered a problem in the circuit just prior to launch. Only launch consoles have this so decided to leave it stock. I since sold it but there so cool and getting rare. It might be worth picking up a A VA3 Genesis or a VA4 Mega Drive if you want to do the jail-bar fix. Should still be able to get a good deal on one on Ebay, The original VA0 consoles are really cool show pieces, and it would be unfortunate to mod. Great that you enjoyed the video & thanks for the sub!

[@davieslm]

@@GameTechRefuge Thanks for the reply. I will keep this stock and pickup one of the models you recommended.

[@emmettturner9452]

@@GameTechRefuge My brother brought a Japanese MD1 back from Thailand last month. We knew it was PAL-modded for SE Asia because it had an RF modulator coming out the side while Japanese consoles normally don’t have one at all. It also had a clock crystal modded underneath the Sony CXA-1145P encoder very much like you describe Japanese VA0 consoles. Unfortunately, it’s a common VA5/6 board so I presume the clock stuff was part of the PAL mod. I removed the extra components and restored the two traces I found that were cut. I then gutted the RF modulator and turned the frequency switch into a language select switch. The gutted RF modulator box is still soldered to the perimeter ground plane at the left edge of the board giving me a place to mount the mini-DIN for the triple bypass (no hole in the back of a JP console without removing the original DIN8). This is going to be a nice build. :)

[@emmettturner9452]

Please revisit this with Tianfeng’s RGB fix that he posted back in November. The 3BP lacks the 5.6k pull-up resistors the model 1 VDPs require for full-range RGB colors. I’d like to know if the color difference you noticed is from that error. Unfortunately, none of my resistor kits has 5.6k resistors. I had completely removed my Sony CXA-1145P encoder anyway so I tried to use the Model 1 originals only to have one shoot out of my tweezers, never to be seen again. :(

[@GameTechRefuge]

I was planning on returning to install pull up resistors. I'm not too keen on the current examples, as they don't look very neat. I'd like to come up with a cleaner way of doing the install. It's a shame there isn't an updated revision of the board, featuring the pull ups. That said, I may create a daughter board that solders directly to the 3BP for now but the best solution would be a new board rev. I'm currently finishing some other projects and I have some minor health troubles that are slowing me down but I hope to return to this later this year.

[@emmettturner9452]

@@GameTechRefuge Tianfeng seems to imply that you should complete the mod, check for the error, then perform the fix if needed. Though they are supposed to have it, most Model 2s don’t really need it. The final rev of the Model 1 is really a Model 2 in Model 1 clothing so it shouldn’t need the fix either. As for how to do it cleanly: If I could go back I’d leave the factory 5.6k resistors in place without lifting the RGB pins then remove the other three resistors on the bottom that connect it to the original encoder circuit. No need to lift pins and no need to cut traces. You can still tap RGB from the vias on top or use the footprints from the other resistors on bottom. Edit: An earlier version of this post incorrectly said that the fix wasn’t for Model 2 consoles though it really is supposed to be there regardless.

[@emmettturner9452]

@@GameTechRefuge …and I hope you feel better soon regarding the health problems. Good luck!

[@NovvaOfficial]

@@GameTechRefuge I just did this on my model 1 and tested with and without the resistor pull-ups. With the resistors in place at the 3BP, I noticed the image was brighter, a bit more saturated on the lighter spectrum of colors. Without the resistors in place, I noticed that the colors were darker and gave the appearance of more depth, until I got to a point in a game were the stage was dark and I couldn’t see any details that I knew were there. --- The only issue I am having now is that I am experiencing the same “hiss” or in the audio. I had this prior to the 3BP and after it. I even used the same 3BP on a secondary board and still hear it. I ordered some HD Retrovision cables to replace my Level Hike adapter I got on Amazon (which may be the source of the audio noise I’m hearing).

[@GameTechRefuge]

Here was my solution. Note: I lifted the RGB pins, that along with being a VA4 model one, this solution is somewhat unique to this type of install. kzbin.info/www/bejne/sJDQm5Vvp9N_q6c

[@segajcharrua]

you can still use the original din. You just have to cut the traces on the din connetor and run wires from the minidin output. also about still using the volume slider its possible there are some components to add on the board. José Cruz and tien fang have posted on how to do it.

[@GameTechRefuge]

I don't like cutting traces. The front stereo sounds good. I'll be giving it a go in the new year

[@emmettturner9452]

I haven’t seen them post anything about how to retain the volume slider… only Firebrand X’s guide to reconnect line-level stereo to the headphone jack without volume control. :(

[@kibecru]

I know it's a year later but I'd love to know how to get the slider working.

[@VLCalaisFanboy]

@@emmettturner9452 I have a VA0 with 3BP V2 board and the volume control works... who ever did the work solded 7 thick shielded wires to the 7 rubycon caps.

[@RWL2012]

This MD1 VA4 PAL is a 1991 one with Motorola MC68000, like Nostalgia Nerd's one. My MD1 VA4 PAL is a 1990 one with April 1990 Signetics SCN68000 (and May 1990 Yamaha YM2612) and it also has a switchless 50/60Hz/region mod. It will be getting an RGB bypass as the sound is fine. My MD2 VA1 PAL has a MegaAmp 2.1, because the RGB video from its Fujitsu MB3514 encoder is fine. This one shouldn't have had sound bad enough to need a Triple Bypass rather than just an RGB bypass... but maybe it did?

[@GameTechRefuge]

Yeah the onboard audio on these is the best. Might get some nice shielded hookup wire to run the output of the front SONY stereo IC back to the 3BP board.

[@StRoRo]

I often wondered if the triple bypass would benefit a MD1. I have the voultar one on my VA4 but there are still jailbars but much better. I did notice my MD1 VA5/6 board has lot less jailbars than my VA4. I wonder if it will be better starting wuth that.

[@pcb123lol]

Both boards use a 7374, so I'm not sure if switching to a tbb board would do much

[@noobguy57]

what pins specifically did you add those 2 caps to? i might try it on my end but i can't quite tell exactly what pins they are. I can look on the datasheet and see what they lead to but I can't count the pins from the video haha. thank you sir, great video!

[@GameTechRefuge]

Let me see if I can dig out an image of that for you. If not I should be able to put something together.

[@noobguy57]

@@GameTechRefuge thank you very much!

[@flyback777]

Great video! What cable are you using from the mini-din to your tv?

[@GameTechRefuge]

I use Retro Gaming Cables in the UK. I use theirs for most of my SEGA consoles. Insurrection Industries in the USA also make some really nice SCART cables, that I use for my playstation 1 + 2 consoles. Both companies make quality leads. *I'm in Ireland so post Brexit, I tend to not purchase from the UK due to import fees . USA to Europe fees can be more cost effective for some things.

[@Razi3l89]

Hi, i want to do the same mod on my model 1 but i want to keep the stock din connector, do you know if there’s a guide or a video explaining how its done?

[@stevezm100]

at 19:54 u added some caps, where did you get these from is in the bypass kit? cheers

[@stevezm100]

and do I need them?

[@GameTechRefuge]

Hi, sorry for the delay in replying. I would recommend adding the capacitors. These through hole types aren;t the best ones to go with. Their just what I had around. A better suited Capacitor would be a 4.7uF MLCC SMD capacitor. A larger footprint size one would be ideal. Many SMD ceramic capacitors are very small so a larger one is ideal.

[@GameTechRefuge]

Dislike? Thumbs up here. **There's a follow up video to this one in the works, to reintroduce the 5.6K pull up resistors. Many of the solutions I found online are effective but very ugly. So I'm looking into creating something neater. kzbin.info/www/bejne/sJDQm5Vvp9N_q6c Audio patch through is also something I'm looking into but I may have to consult with some audiophiles on that one. Thus it may not be in the next video. Rest assured there's loads more Mega Drive content in the pipeline.

[@reggielee31]

I have install md2 din in md1. But there is no stereo output. I don't how to fix it.

[@GameTechRefuge]

If your using an MD2 cable, most don;t carry a stereo signal. So it could be the cable. Double check your soldering but it may be your cable.

[@reggielee31]

@@GameTechRefuge Fixed. Is my speaker problem. Thanks for your reply.

[@haunteddeandollsuk]

i have the triple bypass mod on my pal megadrive but still get those ugly borders around the edges of the screen :(

[@GameTechRefuge]

I think that might be the overscan area. With modern displays you can see it, on older CRT displays it's off screen. Unfortunately on original hardware those color boarders are always there. On FPGA systems and software emulators they can be removed but without some serious engineering by some really smart people there always going to be there.

[@haunteddeandollsuk]

oh thats such a shame, i used to love the older CRT tv but they dont sell them new anymore so I just use my Samsung flatscreen 32 inch tv@@GameTechRefuge

[@8BeatsVGM]

Why triple bypass if it has good sound?

[@Retro-Fez]

I have the triple bypass and still have the jail bars can anyone install the smv capacitors for me would really appreciate it

[@LanceHayabusa]

what are jehailbahawrs?

[@heilong79]

Does not seem worth the work envolved.