Original monitors - any common faults?

[samaron]

Hi!

As the title suggests, I have access to a Sharp CZ-608D monitor through a friend over in Japan. I tried to look up any info regarding common faults that might occur on these monitors. Didn't find much, so it appears not many people use these CRT monitors?

It does power on, and turning up the brightness does reveal some slight burn-in. However, the contrast knob didn't appear to do anything. Is that normal? I see there is a contrast setting in switch.x, so perhaps this is controlled by the computer?

Any typical faults that tend to happen with these that would need some preemptive action if I take the step to ship it over to me?

[kamiboy]

I have one. The only problem that mine had was cold solder joints on the various PCB's. Prolly happened during shipping. Symptoms were intermittent loss of the colour red. First I thought the culprit was capacitors, so I changed them all, which achieved nothing at all. The caps I took out were fine, and the ones I testet were surprisingly within spec even after 30 years. Then I shotgun reflowed solder joints until the problems went away. I believe the contrast knob on mine works.

[samaron]

I see. Perhaps the knob for the contrast is a bit dirty or something. Sounds like if it works, all good. Give it the standard look-over for anything obviously wrong, then?

[kamiboy]

If it turns on an displays a stable and acceptable image then I say there is not much you can ask of a monitor. It is likely caked in dust and grime on the inside though, if you are going to open it up anyway I say clean that up. But read up on how the inside of CRT monitors can be dangerous to your health first so you know which areas to stay away from.

[samaron]

I've gotten the monitor and it works fine! The inside were fairly clean too, barely any need to clean it (though I did brush it a little bit). No burnt components, no leaks, no bulging capacitors, convergence is good, sharp picture, brightness and contrast works flawless. However, it does appear to suffer a little bit from pincushion distortion. The left side has a very noticable curve, while the right side is barely noticable. I've tried to locate a service manual, but no luck there. Biggest part of the problem is Google fighting against me by filtering out foreign websites. I'm not very experienced with CRT displays, so it would help a lot with a service manual to troubleshoot this.

I will start with trying to locate a pot for adjusting this, everything seems to be very well marked. If I can't locate anything, then I have to track down some old technician that can help me identify the correct part of the circuit to troubleshoot.

Anyway, from what I have heard from other people, there doesn't seem to be much that goes wrong with these monitors apart from shipping damage. No typical faults that appear to be common. Guess I got a bit unlucky.

[leonk]

If one gets a standard multi sync 17" CRT monitor from the mid to late 90's. Apart from the plug, isn't it basically the same thing??

[famiac]

No. Most multisync monitors won't support all of the resolutions and frequencies of the x68k. Additionally, the original monitor can be attached to the computer via a control cable, allowing you to turn off and control both the monitor and x68k simultaneously

[samaron]

Actually, this monitor does not have any type of control cable, nor does it support 24kHz. Another multi-sync monitor would do the same job, but where I live they simply do not exist. In fact, CRT computer monitors in general are practically non-existent on the second hand market. To get a CRT monitor I would have to import one from abroad, so thought I might as well import an original one while I'm at it. Since I already spend quite a bit of money importing this original CRT monitor, I might as well attempt getting this pincushion distortion corrected.

I bought a couple of different LCD monitors that the wiki says are multi-sync, but turned out none supported 15 kHz (or 24 for that matter). I suppose the multi-sync part is region specific (only NA markets or something). Since no LCD displays apparently can display the image without cropping it, I opted for a CRT. I do have a XPC-4, but it is slightly annoying with the delay when screenmodes change, it struggles especially with 24 kHz. Plus, the picture gets slightly softer and not as sharp as a direct connection.

[leonk]

WOW .. given how much XPC-4 costs (more than XRGB-mini and heck of a lot more than OSSC) and it's very limited use (basically only Japanese computers) I'm surprised by your findings.

I was still investigating the best way to connect my X68K to displays.

[samaron]

It is a lot quicker than the XRGB-mini. What I mean with delay is that the screen becomes a garbled mess and you have to go into the menu and select automatic adjustment to get it right again. It really struggles with 24 kHz modes, but considering how little actually use it I'd say it isn't a big problem. 15 and 31 kHz usually pops up fine right away. Sometimes after using 15 and you go back to 31 (or vice versa) you have to run the automatic adjustment again because the screen jitters a little bit, or is not resized properly. The picture softness isn't bad, but when comparing it against a direct connection you do see it.

Without an original monitor I would say XPC-4 with a modern display is the best option. Without the XPC-4, a modern tri-sync would probably be the second best, but then the trade-off is cropped picture.

[famiac]

Ah. I wasn't aware the 608D monitor was so useless.

Actually, this monitor does not have any type of control cable, nor does it support 24kHz. Another multi-sync monitor would do the same job, but where I live they simply do not exist. In fact, CRT computer monitors in general are practically non-existent on the second hand market. To get a CRT monitor I would have to import one from abroad, so thought I might as well import an original one while I'm at it. Since I already spend quite a bit of money importing this original CRT monitor, I might as well attempt getting this pincushion distortion corrected.

I bought a couple of different LCD monitors that the wiki says are multi-sync, but turned out none supported 15 kHz (or 24 for that matter). I suppose the multi-sync part is region specific (only NA markets or something). Since no LCD displays apparently can display the image without cropping it, I opted for a CRT. I do have a XPC-4, but it is slightly annoying with the delay when screenmodes change, it struggles especially with 24 kHz. Plus, the picture gets slightly softer and not as sharp as a direct connection.

[samaron]

I wouldn't call it useless. Works really well, and 24 kHz isn't exactly used much. Every game that support it appear to have a 31 kHz mode too.

Spoke with an old technician today, and he said the picture distortion isn't an electrical problem, but a mechanical one. He said either a magnet has shifted slightly on the tube, or it has always been like that. Could very well been acceptable during production. I suppose this is beyond my ability to do something about.

Anyone else with original monitors (or seen several in action) that can report if this is common?

[vanpeebles]

It sounds like a magnet has moved during shipping. I had the exact same thing with a Sinclair QL monitor that was badly packaged. Except it was on all the corners!

[kamiboy]

I wouldn't call it useless. Works really well, and 24 kHz isn't exactly used much. Every game that support it appear to have a 31 kHz mode too.

Spoke with an old technician today, and he said the picture distortion isn't an electrical problem, but a mechanical one. He said either a magnet has shifted slightly on the tube, or it has always been like that. Could very well been acceptable during production. I suppose this is beyond my ability to do something about.

Anyone else with original monitors (or seen several in action) that can report if this is common?

Post a picture of the problem and I can verify with my monitor.

[frankmonk]

I bought an 5:4  BenQ BL912 LED a while ago and this one does 15/31khz just fine.

https://imgur.com/hAMGwHe

[samaron]

I will post a picture later. 

Does the BenQ monitor handle the video without cropping the bottom of the picture? Found a retailer, but costs like 230 USD.

[samaron]

I moved the image so it touches the sides. You can see a noticable difference on the left side between top and bottom, while the right side isn't as bad.

The factory marking on the magnets isn't disturbed as far as I can see.

[kamiboy]

My monitor does not seem to have the same problem, although it is a slightly different model. However, overall I would not call the geometry it produces flawless in any way. There is only so much one can expect of these.

[samaron]

It seems the image is slightly tilted to the left. I'll go over all the pots again and see if I can't find anything for that. Could at least make the left side less obvious. I'm just guessing my way through this, got no experience adjusting CRTs, so for all I know there isn't a pot for adjusting it. Doesn't have to be 100% perfect, but hope it is possible to make it a little bit better, at least.

[Pinwizkid]

Most bends and distortion at the edges of the image are usually cap related. These monitors suffer from the same issues every CRT from the 80s suffers from - old caps and weak solder connections on the potentiometers. Luckily, those parts are all available/fixable!

The original monitors for X68K look fantastic in my opinion (both in design and picture quality). It was expensive and risky for me to import one, but in the end, it was worth it.

[samaron]

As far as I could tell, none of the capacitors were faulty. It is possible have missed something, so will double-check when I get the time. The solder connections are completely fine. I did touch up some that was a bit suspect.

[kamiboy]

I changed all the caps in mine. Did nothing at all. All the capacitors in it were perfectly healthy and within spec even after 30 years. Pretty amazing if you ask me.