There is more than one pinout for 9-pin "VGA-like" monitors. The most likely one is the one used by the NEC MultiSync II monitor, which is very similar to the pinout used by the IBM PGA. Does your monitor have a mechanical switch to toggle between "analog" (VGA) and "TTL" (EGA)? If yes, and you have a digital meter, switch it to analog, and confirm the follwing:

• There is connectivity between pins 6,7,8 and most likely 9.
• There is less than 100 Ohms DC resistance between pins 1/6, 2/7 and 3/8.
• There is no short between any pair of 4,5 and 9.

If all these statements are confirmed, the "standard ebay adapter" is likely the correct way of adapting the monitor.

Just checked the monitor again and there is not switch that would toggle between analog and TTL mode. So I assume it has some kind of auto-detection implemented. I could post some pictures of the insides if it would be helpful...

EDIT: Found a service manual with pinouts, but only for 15 pin connector, it doesn't mention 9pin one. Weird.

Looking at the service manual, the manual obviously describes a different revision of the monitor than you have. PDF page 48 shows how the 15-pin socket is wired at the monitor. As it provides DDC monitor ID information, it is implausible that this kind of circuit is meant to be connected to a 9-pin socket. On the other hand, the drawing of the monitor in the service manual and the photo you linked in the opening post seem to match.

Seeing that the monitor described in the service manual is supposed to handle up to 48kHz, I consider it quite unlikely that this monitor does support EGA at all (of course it does support 640x350 @ 31kHz/70Hz, which is the way VGA used to display EGA modes), so I would expect it is analog only, but an early revision without DDC support and a 9-pin connector. So I suggest you still perform the checks I mentioned in the previous post, and if they check out, use a "standard"/"generic" 9-to-15-pin adapter.

I’ve encountered a variety of early 90’s SVGA 9pin monitors from HP, IBM and other name brands and have never been able to determine the purpose of them as I only recieved the screens Ala carte without the original machine.

Long ago I was able to purchase a 15-9pin vga adapter that thus far worked on all of these screens.

They seem to be an otherwise normal vga/svga monitor so I really can’t figure out the point or if there was some sort of market case where these were used for some reason.

None of these screens did 15khz so in my mind they were pointless.

Would love to see what they attached to.

mkarcher wrote on 2024-10-12, 16:18:

So I suggest you still perform the checks I mentioned in the previous post, and if they check out, use a "standard"/"generic" 9-to-15-pin adapter.

Did the checks and they turned all true, so I guess the monitor is analog VGA all along. I have ordered a small 9-15 pin adapter so we'll see it if works.

rmay635703 wrote on 2024-10-13, 02:36:

Would love to see what they attached to.

I would like to know that too, probably just cost cutting measure? This monitor is from 1996, I guess 15kHz TTL was pretty much obsolete by then.

Paar wrote on 2024-10-13, 16:18:

This monitor is from 1996, I guess 15kHz TTL was pretty much obsolete by then.

At least in the German market, that monitor would be quite at the low end of the market in 1996. A 48kHz SVGA monitor without digital controls and without DDC sounds more like 1994 than 1996. Are you sure that your monitor with the 9-pin socket was built in 1996? Anyway, TTL was no longer to be seen on the market in 1991 to 1992, so this doesn't change the claim that this monitor was built when nobody cared about TTL anymore.

mkarcher wrote on 2024-10-14, 23:13:

Paar wrote on 2024-10-13, 16:18:

This monitor is from 1996, I guess 15kHz TTL was pretty much obsolete by then.

At least in the German market, that monitor would be quite at the low end of the market in 1996. A 48kHz SVGA monitor without digital controls and without DDC sounds more like 1994 than 1996. Are you sure that your monitor with the 9-pin socket was built in 1996? Anyway, TTL was no longer to be seen on the market in 1991 to 1992, so this doesn't change the claim that this monitor was built when nobody cared about TTL anymore.

These 9pin svga monitors are incompatible with TTL as far as I could tell, they “may” work with combined sync or sync on green but as I mentioned they seem like a solution in search of a problem, totally pointless.

The IBM PS1 display that came as a 9pin shipped with a 9pin to 15pin cable in the box.

Again, quite pointless

mkarcher wrote on 2024-10-14, 23:13:

Are you sure that your monitor with the 9-pin socket was built in 1996?

I'm not sure, I just saw it somewhere, either on a website or in the manual. I would have to open the monitor and look for some date codes on the PCB. I could do that when I have the opportunity.

rmay635703 wrote on 2024-10-13, 02:36:

I’ve encountered a variety of early 90’s SVGA 9pin monitors from HP, IBM and other name brands and have never been able to deter […]
Show full quote

I’ve encountered a variety of early 90’s SVGA 9pin monitors from HP, IBM and other name brands and have never been able to determine the purpose of them as I only recieved the screens Ala carte without the original machine.

Long ago I was able to purchase a 15-9pin vga adapter that thus far worked on all of these screens.

They seem to be an otherwise normal vga/svga monitor so I really can’t figure out the point or if there was some sort of market case where these were used for some reason.

None of these screens did 15khz so in my mind they were pointless.

Would love to see what they attached to.

Quite a few 'puprose specific' fixed frequency crts existed in the late 80s to early 90s, that were parts of very early unix engineering worstations.

We had a BOEING surplus outlet back then, and they discarded/sold a bunch of these.

They could do a very limited subset of VGA modes, but were NOT multisync capable, and needed a very tightly pruned frequency table to operate at all. Very few video cards produced their required native sync freqs, and fewer still played nice with windows. (The drivers did not provide a means to set the freq rate, and as soon as those drivers loaded, they set an incompatible refresh, and the screen would freak out.)

At least the boeing surplus ones I encountered were *ALL* large 17", IBM branded. It was a shame they were hobbled in this way, as they would have been very attractive for (then) modern gaming, as this was the era of the dinky 14" monitor still, and large crts were $$$. (And as surplus, they were 🤑.

I fielded quite a few support calls at the mom&pop I worked for over these back then.

Bonafide NEC Multisync / multisync II were 'ugly', but *actually worked*.

As I understand though, EGA can actually be convinced to display on a VGA monitor with a clever resistor pack, as long as it can handle the hsync and resolution. (And knows about sync on green)

I'm mostly replying about where these kinds of monitor found initial deployment.

Again, special purpose unix boxes for industrial CAD, was the usual. A few may have been used for medical imaging, such as from PET or CT scanner.

So I finally had time to properly test the monitor with 9pin -> 15pin adapter bought from China and can happily confirm that it works. Great, thank you all for your inputs!

However there is some issue with the colors. At first everything worked okay but when my daughter tried to power the monitor on, she wasn't able to push the button all the way in and the monitor power on and quickly power off. After powering it on again colors are complete wild, like something would magnetize the screen. Unfortunately there is no button for degauss so what are my options? Maybe external degauss tool? That would be annoying since I don't have one of course. Any idea what actually happened?

Paar wrote on 2025-02-22, 17:01:

However there is some issue with the colors. At first everything worked okay but when my daughter tried to power the monitor on, she wasn't able to push the button all the way in and the monitor power on and quickly power off. After powering it on again colors are complete wild, like something would magnetize the screen. Unfortunately there is no button for degauss so what are my options? Maybe external degauss tool? That would be annoying since I don't have one of course. Any idea what actually happened?

Keep the monitor turned off for at least 15 minutes, then power it up again. It should happily degauss itself back to normal operation.

Okay, tried that but the degauss function didn't fire off. It's probably defective as he monitor should include the function according to the service manual. I'll try to look inside and repair it. In the worst case I could try to use another CRT monitor I have to degauss this one. But that's for another thread I guess.

The main thing still applies - the convertor works 😀.

On cheap monitors, the degauss varistor is always powered and in such a state it is always hot (better monitors use a relay to turn it off after it has done its thing). They eventually burn out, although if you are lucky they just develop bad solders from the heat they're continually generating. It isn't a difficult fix but you would have to go inside and have a spare at hand.

Thanks for the tip, I'll check it out!

Tiido wrote on 2025-02-24, 22:28:

On cheap monitors, the degauss varistor is always powered and in such a state it is always hot (better monitors use a relay to turn it off after it has done its thing). They eventually burn out, although if you are lucky they just develop bad solders from the heat they're continually generating. It isn't a difficult fix but you would have to go inside and have a spare at hand.

You were exactly right! There was a bad solder joint on one of the posistor's legs, as you can see on the photo. I have desoldered the component (which is rated as 14 Ohm) and couldn't measure the rated value (maybe because of the age) but at least the resistance got higher when I heated it. So I put it back, turned the monitor on and colors where normal again. Another weird things is that I didn't hear the classic degauss "boing" sound but perhaps not all degauss coils produce it. If the problem returns I'll try to replace the posistor since the values were weird. I can hear it, it does work.

It's a really nice monitor, picture is sharp and colors vivid. The only things that bothers me is that the picture is tilted slightly. As of now I'm not sure if I have to calibrate it or if the tube is dislocated inside. But that's a problem for another day.

Excellent ~

As far as tilt goes, it is not impossible to tilt the deflection coils but it may cause other issues such as purity and convergence errors... It may be possible to loosen the securing bolts in the corners and tilt the kinescope itself a little bit, that is actually what I did to my main monitor (despite it having actual tilt feature built in 🤣)..