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New 7800 S-Video Board available


Magic Knight

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That is a dual mode upconverter, at least mine is. It can also transcode PAL to NTSC and viceversa.

On my LCD TV straight SVIdeo from the 7800 doesn't work (I tried a personal solution [likely the same schematics you used with the R ladder and the diode and the trimmer etc...] as well as LH), that TV just doesn't sync it very well as the 7800 signal timing is a tad off, composite is instead working fine on the same TV as it goes thru heavy reconditioning (and in my case it looks crappy).

 

Anyway the post is about the converter and the fact that it works quite well alas it does not retain the 4:3 ratio so that has to be forced by the TV (and fewer and fewer support it).

In general the out signal is very good (little lag, I believe 2 frames) but with some sources you can see the interlace going out of sync sometimes (hidef on Saturn and some res on CD32 being the most common offenders) .... I doubt that it is my TV doing that over HDMI so I attribute it to the scaler.

Edited by phoenixdownita
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  • 4 months later...

HI

 

Ive had a couple of PM's laterly so ii guess there is some interest still in this board.

 

There are some still available and fully tested. ( and if you live in the UK, i do offer to install the board and test.) Ive had about 3 turnarounds on installs with sucess (and happy atari users!)

 

If anyones interested in still acquiring (and or fitting), please pm me and i can give rates depending on what you want and location.

 

Richard

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  • 2 weeks later...

I received the board from Magic Knight last year, and my talented friend did a great job with install. I love how he handled the jacks-- they are in the back, and look awesome.

7800.png

 

I checked it out on his monitor, and it looked great, but I need to try a few games out and see how it looks on my PVM 20L5. I'm stoked! Thanks Magic Knight

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  • 4 weeks later...

I am noticing jailbars, at leaat in 2600 mode. Don't have any 7800 carts at the moment. I'm going to try a different s-video cable, but assuming that doesn't work, any ideas on what that could be?

 

Pms already sent beofre reading this, but to recap for any install:

 

* Move the board around / away from the mainboard to see if this affects the amount of ghosting - it may be a grounding issue on your main board. (re-positioning in a more effective area inside may do the trick)

 

* Try turning the trim pot on the S-video card. I dont expect this to be the cause, but it may need adjustment. (remember this will affect the 7800 side also, so a balance is required).

 

* There is a turnpot on the 7800 main board for 2600 tuning - i would adjust this perhaps to get better results. Its not usually needed, however ive done this on my own machines at some point to get the best out of the unit. These can be out of sync and is more forgiving on TV signals as the signal quality is kinda course and doesnt show up as much.

 

* check your grounding from the 7800 to your monitor - this has a mass effect on this and depending on the signal strength, the 2600 may be more prone to this than the 7800 signal because of they are from seperate parts of the chip.

 

* check solder connections (especially from the TIA/2600 parts of the build) - a weakend ground or signal/or signals overlapping too near the board may be causing resonence/inductive interference also.

 

* connections to the TV module (the 4 hard wired pins) should be cut completey before connectivity other wise this drains the power enough to affect the board and must only got to the PCB.

 

 

All boards are tested on the native ATARI prior to region (both using NTSC 2600 and 7800 carts) - so i would test any boards on to North America on a NTSC machine. So im sure its just a solder issue or something similar.

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so...if I had already modded my 7800 for composite video, can this easily replace the composite or be added on with composite?

 

 

If im right and you are using the composite mod that just takes the signal from the (cut) 4 pin connection (intended for the TV modulator) then yes it can, however if you can show/descibe or send a snapshot of the main atariboard with the mod , i can make a more accurate call with this.

 

I sometimes switch from S-Video to Comp and back agian (takes a few minutes of a few solder joints being added subtracted) as im playing around with a 5" mini display unit and do this for testing..., but im aware that there are several composite mods out there and some are not as clean/simple and some sacrifice bits in favour of its new install.

 

Having both would probably mess things up unless there was a 10 pole switch as the S-Video requires more wires at key parts of the board due to the seperate signals for both MARIA and TIA native graphics for 2600. The Composite takes a pre-conditioned signal (typically) and you just take this out at the end of the circuitry, however at a loss in quality. having the signal drain over 2 circuits like this requires one to be isolated and this gets complex although can be done.

 

The S-Video signal however is simply sharp as a tack on a good monitor and translates with great efficiency when upscaled to HDMI.

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  • 1 year later...

I just installed Magic's kit last night on my 7800. Few things I wanted to point out and i will try and get some pics taken tonight to show differences.

 

My 7800 was previously modded by me with the LHE comp/s-vid solution. It worked well, but had severe color bleed issues and contrast problems on both of the LCDs I used and tried it with. That included the Comp video out as well. Also require the switch to cut the TIA 9 chroma signal as I was getting lots of interference in the 7800 signal without it. However, when I used my 7800 on a crt with S-video or my PVM on both comp and s-video it looked fan-damn-tastic! The LHE mod also in the original instructions provided gives unbalanced TIA and Pokey audio with the Pokey lowered too much in volume. Very simple fix for that however.

 

Magic Knight's solution is overall more elegant in the design. It doesn't require any hardware hacking other than the case for the video and audio jacks. Unless you run cables out of the 7800 instead of installing jacks. No resistors need to be cut (except the audio resistors as you read below), you don't have to remove the OR gate logic chip from the board etc. That said, there are some issues still at least on mine and I've notified Magic Knight about this. There is noticeable jailbars in the image that wasn't really present before. I also still have some odd color bleeding, but only Commando really makes this obvious. The colors are bit different on Magic Knight's board. I need to load up and compare between his, my old photos of the LHE mod, and emulation. But I did notice that the contrasting in my opinion is much better with Magic's board. There is a pot on the board to adjust the brightness/saturation and out of the package this was set way too high for either my PVM or my LCD to even accept the signal. I had to lower it a notch. But the overall picture is much brighter with again better colors in my opinion. I would like to see about using a smaller pot to fine tune this even more since anything above halfway on mine produces a scrambled picture signal. I do have my board mounted on the main PCB where the RF modulator used to be so perhaps that is part of the reason for my jailbars. But I seem to recall when I orignally was testing it and had the board outside the 7800 a good 10 inches from the main board that I still had jailbars.

 

Another note regarding the installation instructions that Magic provides:

 

His NTSC guide is spot on, except that on my '84 revision board the +5 is located in the same place off the RF modulator as the PAL system. That is the second pin from the bottom with the ground as pin1 next to it. Magic also has you pull the audio from the same place as the LHE mod, but I would suggest that you cut the north legs (side closest to the back of the 7800 console pcb) and then attach the audio input wire from the clipped legs instead of the south attached legs. I also have a 100uf cap on the output as a filter going back to RCA jack on mine. I have what I consider to be perfectly balanced TIA and Pokey using this setup and it is crystal clear to my ears.

 

Overall I'm sticking with Magic's s-video solution as the ghosting is nearly gone and with the exception of Commando and perhaps a few other games, the color bleeding is pretty much non-existent. I'm convinced that what video issues I'm still seeing is just a characteristic of my 7800 since some of these issues were present on both the LHE mod and Magic's solution.

 

So yeah magic's board gets the edge overall from me. Cheaper solution, much less work to install it and completely reversible. Again I will take pics later of my installation and try and get some good comparison screen shots for those interested?

Edited by -^Cro§Bow^-
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Yeah - not to sound like a broken record, but making s-video mods for any old console in 2015 is a losing gamble. S-Video has been universally dropped by nearly every TV maker. The default standard for legacy TV formats is composite. and really - the quality difference between a good composite signal and your average s-video mod is negligible at best, especially on a TV that is in good shape and doesn't have color convergence issues.

 

I have seen a pretty good difference between S-Video and Composite. It is mainly on darker screens, the darker colors seem to separate more on S-video compared to Composite. Sometimes on Composite, the darker shading seems to all blend together. I have not seen this mod, but I know Svideo is a pretty good step up on other systems.

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I did take pics last night, however as I took them in complete darkness to try and capture the output better, it actually causes havoc with the camera's ISO settings and so they are over exposed. Also not focused as well as I would have liked. So I will redo them tonight. But using (Rev's ?), diag utility I do see much better color separation. That said, I don't know that the color is 'correct', because the ground on Commando now on my 7800 is much too green instead of the brown it should be. And yes, I waited until I had commando running for a good 30min before I tried to adjust the color etc to make sure to give Maria plenty of time to warm up the palette. The jailbars are there, but for some reason are really most noticed on 2600 games? Solaris is a great game to show the jailbars. No amount of moving the s-video mod board PCB around seem to correct this. But the sharpness is much improved on this s-video board and again while the color bleeding especially from blue colored objects is still present, it is reduced at least by 50% of what I had with the LHE board. Again, I think most of the video anomalies I see are just quirks of this particular 7800. We know all too well they weren't created equal and just the variance in brands of parts used throughout from one 7800 to another can impact quite a lot today.

 

I hope to get new screenshots done and posted here later tonight.

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I have seen a pretty good difference between S-Video and Composite. It is mainly on darker screens, the darker colors seem to separate more on S-video compared to Composite. Sometimes on Composite, the darker shading seems to all blend together. I have not seen this mod, but I know Svideo is a pretty good step up on other systems.

oh - there are definitely advantages to s-video, no doubts. it depends entirely on the TV you're using, but it can definitely be better.

 

my point was more about the fact that many TV manufacturers have dropped S-video entirely as the default legacy video input. It's much harder to find newer TVs with S-video now.

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I did take pics last night, however as I took them in complete darkness to try and capture the output better, it actually causes havoc with the camera's ISO settings and so they are over exposed. Also not focused as well as I would have liked. So I will redo them tonight. But using (Rev's ?), diag utility I do see much better color separation. That said, I don't know that the color is 'correct', because the ground on Commando now on my 7800 is much too green instead of the brown it should be. And yes, I waited until I had commando running for a good 30min before I tried to adjust the color etc to make sure to give Maria plenty of time to warm up the palette. The jailbars are there, but for some reason are really most noticed on 2600 games? Solaris is a great game to show the jailbars. No amount of moving the s-video mod board PCB around seem to correct this. But the sharpness is much improved on this s-video board and again while the color bleeding especially from blue colored objects is still present, it is reduced at least by 50% of what I had with the LHE board. Again, I think most of the video anomalies I see are just quirks of this particular 7800. We know all too well they weren't created equal and just the variance in brands of parts used throughout from one 7800 to another can impact quite a lot today.

 

I hope to get new screenshots done and posted here later tonight.

I've read that if you place the video mod outside the tin shielding, it reduces jailbars.

 

I still just used the easier composite mod from the forum here, and I don't really get any jailbars, but I do get a little color bleed from blue like you mentioned.

 

I removed the sheilding entirely.

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I've read that if you place the video mod outside the tin shielding, it reduces jailbars.

 

I still just used the easier composite mod from the forum here, and I don't really get any jailbars, but I do get a little color bleed from blue like you mentioned.

 

I removed the sheilding entirely.

 

I still had lots of jailbar like artifacts on 2600 mode. My initial findings and testing was done while I had it apart still. So i didn't have any shielding on and the jailbars were definitely there. I also did the simple composite mod on another 7800 and while it looked really good on my flatpanel LED and on the PVM, the new owner complained of really bad jail bars on their Sony WEGA they were using it with. So...you just can't win it seems.

 

The composite output from the LHE mod was terrible on this 7800. The overall picture was much too dark and as such had lost a lot of detail in the picture. I believe I have a separate post in these forums with screen shot comparisons of the comp vs s-video on the original LHE mod I had in place.

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Thanks Kindly to Crossbow - Your feedback for the install was very much appreciated and important for improvments going forward!

 

I often get a thanks or no answer when these get sent which is fine also. Crossbow's been very clear and this is important whether good or bad for myself or any developer. Although Im completely on top of the PAL conversion (as most of my half dozen models are of such) im less so on the NTSC in comparison . Ive installed a several NTSC boards, but not seen everything out there - and feedback such as this is always beneficial for improvements. NTSC models are imported in the UK if you ever require these, which is of course costly..

 

S-Video? - this can be easliy converted still for HDMI -

- For the choice of output - Ive seen a few hums and ho's on S-video as a medium - however i cannot stress highly -if you look as this (S-VIDEO) as the best what to get the graphics from the MARIA chip, then you can always upscale on the HDMI which is easy (ive had some 7800's sent to me for upscaling and basic fitting, so its down to choice and Monitor/TV types for this. Composite is satisfactory as such but never the best when you know the native chip give out better....

 

The board is analogue in nature which i see as organic for the screen resolution over digital. This is intended to give a amplified/modulated output from the Maria chip as close as possible to how Atari would have (probably) wanted. -( i can hear the curses being mentioned at ATARI back in the mid-eighties when Nintnedo cracked 'perfect' composite and UHF/RF output was the accountants answer to the graphics at Atari...)

 

The removal of resitors is kept at a minimum and cutting legs off the these always allows you to re-solder, if you decide that hacking parts of the unit is more than bearable, then you can alway turn the unit back to its original state, which is always good.

 

 

If anyones interested - i do still sell these boards for £22 UKP each + postage to your region. (worldwide).

 

Please PM me if your interested and for availability and i can get back shorlty thereafter.

 

If you are in the UK, im willing to perform the supply/conversion if you require (including fitting of the Audio/S-video jack or flying lead as required) - , can do this within a week of reciept of the 7800 and fully test on every aspect for best performance. As ive done several (including HDMI output versions), there should be no issues with the choice of output required.

 

I welcome any questions on this of course!

 

Magic Knight

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As promised here are a bunch of screenshots I just grabbed using my camera off my LED flatpanel using Magic's S-Video board. The camera still makes the pictures out brighter than they actually are but you get the idea. Warning! Tons of unedited pics aside from resizing them to follow?

 

post-6-0-85563300-1481956178_thumb.png post-6-0-02088300-1481956191_thumb.png post-6-0-78499400-1481956199_thumb.png post-6-0-63862000-1481956250_thumb.png post-6-0-89706200-1481956251_thumb.png post-6-0-31168600-1481956253_thumb.png post-6-0-43822900-1481956257_thumb.png post-6-0-91999700-1481956258_thumb.png post-6-0-43376800-1481956260_thumb.png post-6-0-92497400-1481956261_thumb.png

 

 

 

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Second set of pics. You will see the jail bars much more pronounced in some 2600 games as mentioned. I've attached the opening screen of Solaris to show this. Also interesting that other members here have noticed some odd interference on their 2600s and some games that shows consistent patterns on the games. I'm now seeing that same effect here on my 7800 with 2600 games. Again Solaris makes this most obvious.

 

post-6-0-16819300-1481956455_thumb.png post-6-0-94710800-1481956456_thumb.png post-6-0-38405400-1481956458_thumb.png post-6-0-77832300-1481956459_thumb.png post-6-0-42831800-1481956461_thumb.png post-6-0-81566000-1481956462_thumb.png post-6-0-73728200-1481956464_thumb.png post-6-0-43130400-1481956466_thumb.png post-6-0-71720600-1481956467_thumb.png

 

 

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So much green. That doesn't look right

I agree, commando especially. See the screen shots here on this link, it should resemble this:

http://www.ebay.co.uk/itm/ATARI-7800-Console-HDMI-upgraded-with-720-1080-crystal-clear-picture-PAL-/121887285059

 

Monitor/tv settings may need adjusted (RGB?) As the Maria give chroma and lum and not component colours, this may be because of monitor settings and/or the adjustments made from reverting back from the LHE mod. A tweak of the pot on the board may help also.

 

Also Assuming the pots on the Atari main board haven't been ever moved then it's probably not needing adjusted, but no harm in adjusting this and the above for best results.

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I agree, commando especially. See the screen shots here on this link, it should resemble this:

http://www.ebay.co.uk/itm/ATARI-7800-Console-HDMI-upgraded-with-720-1080-crystal-clear-picture-PAL-/121887285059

 

Monitor/tv settings may need adjusted (RGB?) As the Maria give chroma and lum and not component colours, this may be because of monitor settings and/or the adjustments made from reverting back from the LHE mod. A tweak of the pot on the board may help also.

 

Also Assuming the pots on the Atari main board haven't been ever moved then it's probably not needing adjusted, but no harm in adjusting this and the above for best results.

 

Actually commando looks about the same as it always has on both of my led flatpanels. If you notice in the second set of screen shots there is a capture of the color palette from Rev's 7800 diag utility rom. Notice the long poop brown bar at the bottom? You are supposed to adjust your color wheel until both halves of that are the same hue. I've done that and actually matched it using my PVM. I think I will take pics from the PMV next to see if the colors appear any different.

 

For reference, here are some pics of similar shots from the LHE mod I had installed in it previously. Keep in mind that I did replace the missing resistors and undo everything the LHE had me do original to get the 7800 back to stock condition with the exception that I have the RF modulator completely removed. You will notice that the coloring doesn't seem that much different from the LHE in most of the hues, but that the picture was far more muddier with the LHE as opposed to Magic's. These pics were taken on the same flatpanel under the same conditions but I took them zoomed in a bit more. I can tell you that some of the interference patterns that appear in these shots, aren't there in actuality and appear to be something my Nikon generates when I take pics from TVs like this. Also since there is other light in the room which is needed for my camera to focus on the screen properly, some of the 'interfence' could in fact be reflections in the screen. You will also notice how much worse the color bleeding was with the LHE as opposed to Magic's.

 

post-6-0-19241300-1481995060_thumb.jpg post-6-0-34418400-1481995065_thumb.jpg post-6-0-28772000-1481995062_thumb.jpg post-6-0-33435100-1481995064_thumb.jpg post-6-0-24563300-1481995059_thumb.jpg post-6-0-28618500-1481995063_thumb.jpg post-6-0-18672300-1481995058_thumb.jpg post-6-0-22656900-1481995061_thumb.jpg

Edited by -^Cro§Bow^-
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Actually commando looks about the same as it always has on both of my led flatpanels. If you notice in the second set of screen shots there is a capture of the color palette from Rev's 7800 diag utility rom. Notice the long poop brown bar at the bottom? You are supposed to adjust your color wheel until both halves of that are the same hue. I've done that and actually matched it using my PVM. I think I will take pics from the PMV next to see if the colors appear any different.

 

For reference, here are some pics of similar shots from the LHE mod I had installed in it previously. Keep in mind that I did replace the missing resistors and undo everything the LHE had me do original to get the 7800 back to stock condition with the exception that I have the RF modulator completely removed. You will notice that the coloring doesn't seem that much different from the LHE in most of the hues, but that the picture was far more muddier with the LHE as opposed to Magic's. These pics were taken on the same flatpanel under the same conditions but I took them zoomed in a bit more. I can tell you that some of the interference patterns that appear in these shots, aren't there in actuality and appear to be something my Nikon generates when I take pics from TVs like this. Also since there is other light in the room which is needed for my camera to focus on the screen properly, some of the 'interfence' could in fact be reflections in the screen. You will also notice how much worse the color bleeding was with the LHE as opposed to

Crossbow - Forgot to ask - have you at any stage adjusted or are looking at adjusting R56 and R57 pots on the 7800? I recall trimming these on one of my more 'knackered' pal units as they had poor colour until they were trimmed for best results.

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