No 31k image

[LowDefAl]

I'm currently having no luck getting a 31k image from my x68000.

I originally had a vga adapter that came with the machine. It worked fine but recently became damaged. I've just replaced the sync chip near the internal rgb header as per the wiki because it became clear that I was having difficulties creating an Scart cable for my PVM, despite it previously working when piggybacking a scart header onto the adapter some time ago (long before it stopped working).

After replacing the sync chip I can indeed get a 15khz image using a premade X68k to Scart adapter I bought on eBay. I think it needs a proper sync combiner but it works with puyo puyo so I'm taking that as a success. However I can not make a working VGA adapter/cable. I've tried several times and checked the various pinouts but can not see an obvious issue. The current attempt at the cable was done carefully with good isolated joints and protected with heat shrink so I don't think it's a workmanship issue.

Have I missed something that could cause a monitor not to see a signal from a vga cable? I've tried two different monitors (one was one of the screens I originally used) and used different vga cables but the monitors won't see a signal. I know the 31khz signal itself shouldn't be damaged as it displays in a glitched manner on my PVM (it will display side by side images of the signal such as the insert disc prompt and boot screens)

In all of this the machine has now forgotten it's memory setting so I can't play any 2mb games now and I don't have a keyboard to change it. It's going great this week. 

[LowDefAl]

I was able to fix the blown fuse on my OSSC so I've been able to some more testing.

I now have 3 vga adapters which all give the same result. No sync signal is detected by vga monitors. The OSSC also does not detect a sync through these adapters. I do not have a CRT VGA monitor to test with.

However the OSSC will accept a signal from the scart lead I recently acquired at both 15 and 31khz. I've also tested a a few different games as Puyo Puyo hides a lot of issues which prevented analysis of the issue. There is a weird colour banding issue. It sometimes goes across the entire line, breaking into the black border - this may be video mode dependant. Using the scart lead direct with the BVM shows a slight wobble in the image even in 15khz which doesn't show with the OSSC. Could this banding and "spillover" be somehow confusing the sync for vga monitors?

I have absolutely no idea where to start in further diagnosis or fixing it. It's possible another IC needs replacing or perhaps something on the RGB board but I'd rather not start hacking away at it randomly. I've checked the replacement chip is seated in the socket and reflowed the socket pins but it's made no difference. I do have two spare chips I can try but I'd be surprised if the one I put in was already bad.

[skpstmgs]

Not sure how helpful this is, but I briefly tried using my X68000 with the OSSC and the image quality was very bad. I forget the exact issues but it seemed pretty hopeless. I also remember trying it on my PVM 20L5 using on of those Arcadeforge sync combiner things, and the image quality was also bad on that. Seems like the only thing that works well is the XPC-4 upscan converter or a PC CRT for 31KHz. I haven't tried using it directly with a modern LCD though.

[kamiboy]

Ueah, the video signal from the X68000 is far from standard, this is the case for both 15khz and 31khz games. Using upsclarers meant for regular old consoles is not likely to work.

To get my A20F1 to show 31khz through two different devices, and even then 15khz flat out does not work.

[SuperDeadite]

No idea if this will help the op, but one thing to remember is that X68000 actually runs at 55Hz. This can be hell for modern devices.  I use an arcade CRT monitor, and it truly is a thing of beauty.

[LowDefAl]

Hopefully my replies to some of these comments might clear things up a bit. I have a habit to ramble and not be clear, and this was one of those occasions.

Not sure how helpful this is, but I briefly tried using my X68000 with the OSSC and the image quality was very bad. I forget the exact issues but it seemed pretty hopeless. I also remember trying it on my PVM 20L5 using on of those Arcadeforge sync combiner things, and the image quality was also bad on that. Seems like the only thing that works well is the XPC-4 upscan converter or a PC CRT for 31KHz. I haven't tried using it directly with a modern LCD though.

Not only has the OSSc given me a decent image, a friend of mine used some footage for a video and it came out fine. I didn't even use a fancy capture card, just an Elgato Camlink and it was an experiment but went quite well. I believe it's results can depend on the monitor you are using but I had it working fine plugged into a Dell display I have which doesn't have VGA.

As for the sync combiner I believe this was a false flag on my part.

No idea if this will help the op, but one thing to remember is that X68000 actually runs at 55Hz. This can be hell for modern devices.  I use an arcade CRT monitor, and it truly is a thing of beauty.

According to the OSSC it was reporting various rates between 55 and 61. My Dell handled it fine as did the camlink. I'm aware this is highly monitor dependant but even when I was going straight into vga monitors it was accepted fine. The monitor's interpretation of the resolution and such was unsurprisingly variable but they put functional images on the screen.

There seems to be a damage-flicker glitch in Castlevania where Simon will vanish on some displays but using the OSSC this wasn't evident. I assumed this was refresh related but couldn't confirm.

I dropped my last arcade CRT and smashed it which I probably regret more now than I did at the time 

Ueah, the video signal from the X68000 is far from standard, this is the case for both 15khz and 31khz games. Using upsclarers meant for regular old consoles is not likely to work.

To get my A20F1 to show 31khz through two different devices, and even then 15khz flat out does not work.

Again, It worked fine before.

I seem to have an uncommon problem. It worked fine with vga monitors and then with my OSSC. Then I started making my own cables and I assume I did something wrong such as shorting something. I was getting an image that rolled across the screen like crazy so changed the 74ALS05 because it was the typical thing to do with video issues. This has restored a "working" sync through 15khz scart and a sync for 15khz and 31khz via scart with the OSSC. I'm still unable to get anything to sync with vga at 31khz.

I should note I've been zapped a couple of times by the RGB module when I had the cover off and was stupid enough to not disconnect it from the step-down while removing the video cable. I dare say this hasn't helped.

[leonk]

I hope this helps.

- I have made 2 RGB cable's for x68k and they both were tested on pc monitor and ossc. No issues. Tested with original x68k and compact red zone edition.

- X68k puts out RGBHV. RGBS (what scart is) requires H and V to be combined. I noticed that scart cable makers just tie H and V together!  Not a fan of doing it this way. One needs to use something like an extron to properly convert HV to composite sync.

- I have tested the scart cable with HV tied together on xrgb mini and it works great for both 31k and 15k

my suggestion to you is make your own cable. Get a VGA cable and a db15 male socket + shroud. Then follow the instructions on the wiki + wikipedia to connect grounds together. H and V. and finally R G and B.
Don't trust the premade adapters. many and made incorrectly.

[LowDefAl]

As previously stated I've already made several cables, checked, remade and rechecked several times and none of them work. I've made them with and without video grounds. I've used several identical pinouts in the process and have probably spent 3-5 hours just doing this. The premade adapter I originally got with the system worked fine until I started experiencing the problem.

As for tying H+V this was my original thought and yet it's still actually giving me an image so it's better than nothing and it's the only reason I know the system is even generating video still. As far as I'm aware it only needs a logic gate and not an entire scaler/processor. Even when I made my original piggy-back scart cable it didn't have that weird colour issue.

I can't see how Cables, scalers and monitors are the problem. I can rule all these out based on previous usage and the several hours spent on it since. Something isn't right inside the console as I should be getting something synced over vga. So either my replacement ALS05 is faulty or the problem is still in another IC (or even some caps).

[LowDefAl]

In the absence of any clue what to do next I'm going to try replacing the ALS05 again. I added a socket when first replacing it and I have two spare chips so it's a quick way to eliminate the possibility of a faulty chip. I'll make sure to partially reassemble the system properly to reduce the chance of me/the system getting another shock. If this doesn't work I'll consider replacing the neighbouring chip and recapping the rgb module. 

[LowDefAl]

IT LIVES.

I changed the ALS05 and initially it didn't make any difference and I had no signal over the scart cable or vga but then I noticed it wasn't firing up the floppy that was in the drive. I took the shielding off the motherboard, wiggled the ALS, reassembled the shielding and rgb module and it started up with a signal over scart through the OSSC.

I swapped over to vga and it synced right away. I then swapped over to a vga monitor and it again worked. So problem solved. I'm still none the wiser as to what the problem actually was. It could have been the chip but both of the ones I tried were brand new from the same supplier.

[kamiboy]

If wiggling it helped then either the socket is a bit dodgy, or maybe there is a cold solder joint. If the problem returns then it is prolly a cold solder joint, and you should reflow the legs.

[srtomiz]

IT LIVES.

I changed the ALS05 and initially it didn't make any difference and I had no signal over the scart cable or vga but then I noticed it wasn't firing up the floppy that was in the drive. I took the shielding off the motherboard, wiggled the ALS, reassembled the shielding and rgb module and it started up with a signal over scart through the OSSC.

I swapped over to vga and it synced right away. I then swapped over to a vga monitor and it again worked. So problem solved. I'm still none the wiser as to what the problem actually was. It could have been the chip but both of the ones I tried were brand new from the same supplier.

Hi, sorry for bumping this old thread but it's the color banding problem gone too?, I'm having the very same problem as you with my ACE and a framemeister, the very same issue, If I use a vga cable and a LCD monitor the problem is gone but over scart over the Xrgb the colors are all over the place.

In my case works fine as far as I can tell, it's just the messed colors over SCART.

[LowDefAl]

No, in fact the problem returned a few days later when I retested and I couldn't work it out. I did start replacing more of the video chips but a combination of difficulty cleaning some of the holes and the possibility of actual motherboard damage led to me just buying another machine and keeping the old one for spares. I haven't attempted to continue the repair as of yet.

However I did learn that in fact I had damaged the VGA port on my OSSC, presumably at the same time I damaged the video output because it doesn't sync now even with a working machine (scart is still fine). Have you checked your xrgb with another source? A recent discovery (by Leon I think) suggests the possibility of the XRGB not necessarily being safe to use with a scart cable given the voltage coming from the X68k's sync signal.

[srtomiz]

Thanks for your quick answer, the framemeister works fine with all the consoles and computers I got around so I know it's fine.

I think I'll stick with the SVGA port for the moment (If I can choose I prefer to bust my monitor vga port than my XRGB) until I can get hold on a multisync monitor.

Regards.

P.D: I've just read Leonk post and jeeesus, that was a close call, thank god didn't fry my framemeister... no more SCART cable for me.