MSX problem (faulty cable?); need help!

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By ave

Rookie (20)

ave's picture

14-03-2010, 00:55

hey guys,

I just registered here. Afterall my MSX2+ F1XV arrived only the day before yesterday, so I had basically no right to enter this area of the net until recently Wink
A couple of months ago I finally decided to buy an MSX computer because I want to play the exclusive Konami shooters on the original hardware! I succeeded getting a Sony MSX2+ F1XV in flawless condition and got it yesterday by seamail from Japan. Big smile

But here's the issue. I can't get the video signal straight, it keeps flickering or scrolling. When I connect it to my Philips CM8802 monitor (50/60Hz RGB), the picture is just "scrolling" really fast. I attached a picture of it:

img194.imageshack.us/img194/9373/msx1.jpg
I decided to try connecting the MSX with my rgb TV and it looks much better, but the picture still "scrolls" about once a second and certain areas are "wobbling".
img706.imageshack.us/img706/5545/msx2.jpg
img268.imageshack.us/img268/7558/msx3.jpg
I tried to capture that effect on the last picture with the blue screen and text. The text is wobbling back and forth and not just bent to the right as you can see on the picture.
My guess is that it is caused by the cable because the MSX itself boots and plays cartridges perfectly fine, but the video signal i.e. gets worse when I reconnect the cable: The image shifts when reconnected whilst the MSX is switched on, like the bottom of the picture is right in the middle.

My RGB-cable is an 8-pole DIN->Scart RGB, selfmade by someone from the Netherlands. Both monitors have been tested with NTSC 60Hz RGB-input from various Japanese consoles, so they definitely are not the problem.

I am grateful for any help. I feel the great playability even with the flickering picture that makes it almost impossible to spot enemy bullets, but despite all the difficulties I try really hard to play Gradius 2 with my XE-1 Pro. Can't resist... LOL! What would it be like without wobbling, flickering graphic scramble? >_<

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By Jipe

Paragon (1560)

Jipe's picture

14-03-2010, 09:26

i see a multiple scart , unplug it and try directly on scart TV

for your monitor try in BASIC

VDP(10)=2

this instruction forced in 50Hz mode , if the screen is ok the monitor don't support 60Hz of Japan MSX

By AuroraMSX

Paragon (1902)

AuroraMSX's picture

14-03-2010, 11:32

But here's the issue. I can't get the video signal straight, it keeps flickering or scrolling. When I connect it to my Philips CM8802 monitor (50/60Hz RGB), the picture is just "scrolling" really fast.
That's what missing VSYNC looks like Smile Since the MSX seems to be ok and you're dead certain that also the monitor is ok, then the next step would indeed be checking the cable. Check the Ultimate MSX FAQ for the pin-outs of the connectors...

I decided to try connecting the MSX with my rgb TV and it looks much better, but the picture still "scrolls" about once a second and certain areas are "wobbling".I guess you're living in a 50Hz area? Then most probably your TV set can actually only handle 50Hz signal and is doing its very best to keep up with a signal that's 20% out of spec :) Try Jipe's suggestion and see if that gets you a more stable image on your TV.

By ave

Rookie (20)

ave's picture

14-03-2010, 14:57

@jipe
No difference when connected directly to the TV. I tried the Basic command and apart from the obvious change in format, it won't change anything to the better (still flickering). My TV is also 100% capable 60Hz, NTSC-RGB etc., I've tested that with several Japanese consoles.

BUT I also tried to hook it up with a standard cinch / rca cable (yellow + sound) and this way I get a perfect picture (perfect in terms of a composite signal of course). No flickering or wobbling at all in both modes, 60 and 50Hz.

@aurora
I live in a 50Hz area (Germany), but my monitors/TVs are all supporting 60Hz, couldn't live without it. Because that can't be the cause of my problem, I just opened the cable. I believe the synchronizer must be the brown cable, but it looks reasonably soldered:

http://s10b.directupload.net/images/100314/qat9aauk.jpg
http://s11.directupload.net/images/100314/hk2uuqhf.jpg

By Manuel

Ascended (18958)

Manuel's picture

14-03-2010, 16:38

So either something is wrong with the cable or something is wrong with this MSX.

By RetroTechie

Paragon (1563)

RetroTechie's picture

14-03-2010, 21:43

Or one of the contacts on the motherboard -> 8-pin DIN connector is loose. Happens easily (over time, many connects/disconnects), since a DIN plug exerts relative big force on the small connector. If pushing the DIN plug in different directions (while connected) suddenly makes the image go "okay!", that would be a sure sign.

This problem is very common for joystick connectors, and easily fixed. But it would require soldering iron & disassembly of the machine, to get to underside of mainboard... Sad

You might want to try and replace the sync signal (might be composite video, it would be the signal going to SCART pin 20, yellow in your picture?), with a composite video signal picked up from other connector (cinch plug). Just for a few seconds, to see if that fixes the image. If yes, you're looking at faulty/missing sync signal on the computer's RGB connector (for whatever reason). But first check that cable itself, of course! (see comment above on pinout).

Btw. good choice - that Sony is very nice MSX2+ machine. And Sony generally built their products well in those days... Smile2

By ave

Rookie (20)

ave's picture

21-03-2010, 15:17

Update:

I got another RGB cable yesterday. I'm quite sure, however, that the cable is not the problem: the problem comes up with both RGB cables and they look very tidily soldered.

I then proceeded by opening the MSX to have a look at the RGB DIN connector, here's a picture of what it looks like on my MSX2+:

http://img444.imageshack.us/img444/5946/img3754.jpg

Can you guys infer something from that picture that could help me with my problem?

By bore

Master (145)

bore's picture

21-03-2010, 16:18

Everytime someone connects or disconnects the connector some of force will be applied to the solder joints of that connector. (Happens to all PCB mounted connectors.)
My guess is that one or more of the solderings on that connector is broken, I have seen this on several occations.
You could have a look at the PCB from the other side to see if you can spot the pin (It will probably have a darker ring in the solder or a gap between the solder and the PCB.) but sometimes it's hard to spot.
I would just bring out the soldering iron and resolder that connector and see if it helps.

If it doesn't help you should bring forth the multimeter and measure the resistance between the pin on the connector and the other end of the cable when it is connected to see if the connector is broken. If not then you probably have a damaged chip somehere.

By Leo

Paragon (1236)

Leo's picture

21-03-2010, 16:47

yep i had to refresh soldering also on my sony hb700 ,

By AuroraMSX

Paragon (1902)

AuroraMSX's picture

21-03-2010, 22:56

I live in a 50Hz area (Germany), but my monitors/TVs are all supporting 60Hz, couldn't live without it. Hm, okay.
I then proceeded by opening the MSX to have a look at the RGB DIN connector, here's a picture of what it looks like on my MSX2+:

http://img444.imageshack.us/img444/5946/img3754.jpg

Can you guys infer something from that picture that could help me with my problem?Not really. If this is the problem, then it's on the bottom of the PCB - where the soldering is.

Do you by any chance happen to live in or near Munich? I'd love to meet a fellow MSX-er in my 'hood :)

By ave

Rookie (20)

ave's picture

21-03-2010, 23:43

The next big city is Hanover, Munich is a five-hour trip by car unfortunately. :/

Okay, the next task will then be to gain access to the bottom of the PCB? That doesn't sound too pretty, considering all the screws and cables I'll have to remove in order to get there. It'll probably take a while, but I've got some free time this week so I'll probably come up with more questions quite soon. Smile

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