Panasonic A1-WX RGB Out Issues

By Crushy

Supporter (1)

Crushy's picture

04-07-2019, 00:32

Hello everyone! You may have seen my recent conversation in discord as "Crush" Thank you all for your help so far with this issue as it's been a bit of a ride the past two months.

In May I picked up this MSX2+ off of an auction in Japan and to my delight it works great, the computer functions, reads cartridges, and I've repaired the FDD with a new belt and cleaned everything up. Im really happy with the system so far.

Although I've run into a pretty frustrating issue with the RGB port on this computer. Though im able to use Composite Video and Sound just fine, the RGB port does not produce any video, not even a black screen, a flicker, or anything that could signal that the port is working. However, I do get sound from the port just fine, im able to hear games start up and play.

I've used a Multi Meter on the port, but it looks like it's shielded in black plastic that I cant seem to remove, my probes are a bit bigger so im not able to test the actual pins inside. Although on the bottom of the board I was able to get a good reading from the RGB solder joints as well as the composite.

Im running this computer though an XRGB Framemeister though SCART. I have two cables so far, one from retrocables.es and another from ebay, they both produce sound but no video signal. I've purchased another from the Packapunch Retro Cables in the UK but it has not arrived yet. The adapter I use for the framemeisters RGB is 21-Pin to XRGB Mini with Sync Separator. I've also attempted with a Japanese adapter but afraid that I might harm the system in a way.

Im wondering what the next step would be here, I would assume that I would get at least some sort of flicker or static if the port was working, but some have said the RGB port must work if composite is working. Im really bummed about the project, if theres anyone that is experienced with repairing these types of things, to resolve this issue and maybe add on board memory I would be more than happy to pay for your services!

My apologies for the long post! I wanted to give you guys as much information about the issue as possible. You can also find me in the MSX Channel discord as "Crush"

Have a great rest of your night and thank you so much! Smile

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By Wild_Penguin

Hero (542)

Wild_Penguin's picture

04-07-2019, 10:10

I'd suspect you have the wrong cable. There is no standard for the DIN connector used. See: here for various pinouts -> click "RGB output"

EDIT2: Are you using the XRGB Mini Framemeister? If so, are you sure you are using a SCART adapter and not a RGB21 adapter, which comes with the device?

It could also be that the connector itself does not give good contact / is worn. I had a AX-350II with an obviously worn connector, but that was easy to diagnose.

With RGB, you will usually not get a flickering picture. It works differently; absence of picture means both sync signals are not connected (or composite sync, in the case of SCART RGB, is not connected). If the device can SYNC, it should at least report it (60Hz something in this case - does the Framemeister or you display report it?). After that, you need R, G and B, and if one of them is missing, then that color component will be missing.

EDIT: I'm bad ad reading, scratch the previous paragraph. You don't get sync signal from your MSX or the Framemeister can not interpret it.

I don't remember the different Framemeister version differences (never even owned one), but are you sure it can handle composite SYNC? Which Framemeister do you have? Some might only accept separate SYNC. Some devices are picky, and don't like the composite video signal embedded with CSYNC (in which case, you need a SYNC stripper). Framemeister might be one such device. Of course, we haven't established here if the FS-A1WX even outputs composite video at the sync pin or already clean composite sync.

For example, my projector (which only has a VGA connector and officially doesn't even support composite sync) does not like composite video as sync source. But after using a sync stripper (and amp - it could also be an issue with differences in SCART/VGA levels), it works just fine with my MSXes (and also, has no problems feeding SCART level RGB trough the VGA connector).

EDIT^(4*i): Bad reading, part 3½: I noticed you are already using a sync stripper. Chances are still there is something wrong with your cables. The thing is, the composite and other signals are usually derived from the RGB - so their presence already indicates the MSX video output is working. There could be a cold solder joint somewhere, but those are usually (not always!) easy to spot. Namely: A lifted solder pad with a fracture in the trace/solder border, can be really difficult to spot! Check connectivities with a multimeter, but I've red you already did some of that.

EDIT: The bbcode parser on this forum and URLs... ah well :RNFF: - also a few clarifications

By RetroTechie

Paragon (1563)

RetroTechie's picture

04-07-2019, 21:42

Wild_Penguin wrote:

Of course, we haven't established here if the FS-A1WX even outputs composite video at the sync pin or already clean composite sync.

For the FS-A1WX, composite sync only. Basically V9958's CSYNC output passed through a buffer.

By gdx

Prophet (2978)

gdx's picture

05-07-2019, 02:30

I also think your cable is not adapted. You probably need a RGB21 or SCART cable. Another possible reason: Some European TV need the 12V signal to switch to RGB mode.