Skate finds a iigs

[markyb86]

My only complaint is that this monitor model has virtually no ventilation by design. I may have to look into adding a small fan at some point. It really gets warm after a couple hours.

Have you considered cutting into some of those grooves on top top make vents? With small enough tools it might come out pretty nice. 

The picture on that thing is really good actually!

 

[Skate323k137]

Yeah, looks great!  Did you replace most/all of the caps inside - did it improve picture quality/brightness in doing so?

The 12" RGB is a great monitor to own if you're into other 15khz output Amiga/Atari systems of the same age, I'm going to make up the cable one day on mine to get it working on those too.  

JB

Thanks man! I did a full cap kit from console5.com, as well as the resistor they recommended. Definitely an improvement, the monitor was unusably dim previously. I'm not huge into Amiga stuff (some day maybe) but tons of arcade boards run on 15khz rgb. I can always use a 15k display for something.

Have you considered cutting into some of those grooves on top top make vents? With small enough tools it might come out pretty nice. 

The picture on that thing is really good actually!

I have.... The only vents at all are the top and it's at 90 degree angles to presumably keep dust out. If I make any holes on the case it will be to be able to reach screen/focus with the case on. Other than that I would hope I can squeeze a fan in somehow. Anything at all should do the job. 

 

[NJRoadfan]

Nice to see the free aliasing filter (thanks to the cruddy dot pitch) blending the SHGR 640 mode colors. The most annoying thing about these monitors is the moire pattern they always seem to produce on the Finder background.

 

[CC_333]

Nice to see the free aliasing filter (thanks to the cruddy dot pitch) blending the SHGR 640 mode colors. The most annoying thing about these monitors is the moire pattern they always seem to produce on the Finder background.

I wonder if it was by design?

Or is it that most of these displays don't do that?

c

 

[Gorgonops]

The most annoying thing about these monitors is the moire pattern they always seem to produce on the Finder background.

Whoever thought that the best idea for the finder background was a series of one pixel wide pinstripes really deserves to be taken out behind the shed and shot. Sure, contemporary monitors (mostly) successfully blended it into something that looked vaguely like a solid color, but it really looks like hell on more modern displays. (And it also looks like absolute murder on a composite screen, but that's pretty much true of any output with that many pixels on composite.)

I wonder if it was by design?

The Moire patterns, no, the 'aliasing' effect, yes. The IIgs heavily relies on dithering to fake like it has more colors available in the 640-dot-wide screen resolution than it really does. It was actually in their interest to have a display that wasn't the sharpest tack in the box.

(One of the reasons I'm not particularly pleased with how my IIgs looks when connected to the cheap arcade scaler board I have is the board *isn't* fooled by the pinstripes into displaying a solid light blue and instead renders them sharply on the VGA output; this looks bad and it's made worse by the slightly irregular line thickness you end up with because of the non-linear scaleup.)

I think I'll concentrate on getting another IBM 5153 monitor though, first.

If you'd be happy with just having a digital RGB monitor I'd suggest looking at, I hate to say it, the 108x-series monitors that Commodore sold for the Amiga. (These monitors were actually rebranded... Magnavox? units, but the equivalent units with the original label are really hard to find.) Most of these monitors have both analog and digital RGB ports (along with composite) and thus can be made to work with most 80's home computers.

 

[Skate323k137]

Whoever thought that the best idea for the finder background was a series of one pixel wide pinstripes really deserves to be taken out behind the shed and shot. Sure, contemporary monitors (mostly) successfully blended it into something that looked vaguely like a solid color

THIS. Even on a CRT honestly it was like the test pattern from hell.

One issue you run into focusing these things with shitty dot pitch (and also not being aperture grille) is your thickest scanline might not be your best picture. You touched on that with "It was actually in their interest to have a display that wasn't the sharpest tack in the box."

I could basically over-focus it to a point where you could seriously see the grille and each R G and B dot. You almost have to "loosen" the focus from that exact point to get good whites and colors. Definitely not a trinitron, but nonetheless, I'm happy to have the original monitor restored that came with this machine.

 

[EvieSigma]

If you'd be happy with just having a digital RGB monitor I'd suggest looking at, I hate to say it, the 108x-series monitors that Commodore sold for the Amiga. (These monitors were actually rebranded... Magnavox? units, but the equivalent units with the original label are really hard to find.) Most of these monitors have both analog and digital RGB ports (along with composite) and thus can be made to work with most 80's home computers.

Or uh, y'know, the Tandy CM-11, which is much cheaper than a 1084 in my experience...

 

[Gorgonops]

Or uh, y'know, the Tandy CM-11, which is much cheaper than a 1084 in my experience...

The reason I suggested the Commodore monitor is because it does *both* digital RGBI and analog RGB. The CM-11 is *just* a digital CGA monitor. Therefore a 1084 can be a really handy thing to have lying around. (I have a 1084 and it's on my to-do list to make an adapter cable to use it with the IIgs. And of course it works with the Apple II+, the Amiga it came with, would work with a CGA PC if I ever pick one up again...)
 

But, yes, if you just want an RGBI monitor the CM-11 is a fine choice.

It's off-topic for this thread, but another option if you do have an old PC with CGA and you're desperate for a monitor you can connect it to those cheap scaler boards with an inexpensive adapter; said boards are designed for analog RGB but RGBI can be converted to that with a simple DAC. (The simplest version can be made out of just resistors, but this won't look quite right because IBM CGA monitors have special circuitry inside to convert what would be the "dark yellow" color you'd get out of the straight RGBI equation to a more aesthetically pleasing brown. Several people make adapters equipped with a chip that will do this. You can, oddly enough, most easily find sources on forums talking about Commodore 8-bits because the Commodore 128's RGB output is the same as CGA.)

... of course, if you bought the PC to play games on you're *actually* probably better off connecting it to a composite monitor if you have a composite-equipped CGA card, but that's a really off-topic subject.

 

[Skate323k137]

If it has to do with analog /digital / old RGB video I don't mind

The bigger monitor I use the IIGS with has both analog/digital RGB inputs on the back. NEC CM-27 is the model if I remember right, but I've only ever seen the 2 I salvaged, and I sold one of them. 

 

[Gorgonops]

Seeing photos of a IIgs connected to the original monitor or sufficiently blurry TV sets (via SCART cables) it's kind of shocking how much better its desktop looks than it does on a monitor sharp enough to resolve the pinstripes. (Or in an emulator, for that matter.) It's "blurry" but it's not a stripey eye-killer.

(It's funny, I don't think I ever actually saw a IIgs running GS/OS in person before getting one myself. The IIgs came out right about the time I graduated from middle school, and that was the highest grade level that had Apple ][s; high school was 100% IBM compatibles.)

What really kind of gets me about this is I'd swear that if you displayed a similar pinstripe pattern like that on an IBM PC with a CGA monitor it wouldn't "blend" anywhere near as neatly as that. I can't swear to it, though, because most of my memories of CGA involve it running on monochrome monitors. (Our first PC had a Princeton Graphics MAX-12, like this:

https://picclick.com/Vintage-Princeton-Graphics-Systems-Ibm-Computer-Monochrome-Pc-322438777633.html

Which was an interesting dual-mode monitor that could handle both MDA/Hercules and CGA in shades of amber.) I did for a while in the early 90's have a ridiculously tricked out 5150 (made out of scrounged parts) that had an EGA card connected to a Kaypro CGA monitor and... yeah, again, I'd swear that pinstripes like that didn't 'blend' the way they seem to on the IIgs monitor. (IE, a series of blue and white bars would be clearly identifiable as such, to see it as a dithered color you'd have to take a few steps back and depend on your eyes to mix it.) Maybe I'm mis-remembering, or maybe Apple really did sort of "de-tune" their monitor to make dithers more effective.

 

[EvieSigma]

Pretty neat monitor, but if I'm gonna have a monochrome monitor I'd like to get an amber Amdek unit.

 

[Gorgonops]

My favorite ever monochrome monitor was a green NEC-branded composite-input unit. (Looked a lot like the contemporary Amdek ones.) It had a built-in amplifier and speaker which made it particularly handy to use with the TRS-80 Model I (I made a cable with phono-plug jack on it to connect it to the cassette cable, which was the standard method of getting sound from games with a Trash 80), and I also, just for laughs, had it connected to an old VCR and running as a television for a while. It had a *sloooooow* phosphor tube which left satisfying "action blurs" when playing video games. (And could have some trippy side effects when watching TV.)

Personally, having had both, I feel like Green > Amber. In particular if you're talking about MDA with its sloooow 50mhz refresh the longer persistence your phosphor the better. The MAX-12 was fine for CGA at 60hz, but I tried it on a Hercules card for a while and it gave me a headache.

 

[Gorgonops]

... and, I guess to be clear, what was special about the MAX-12 (and some later monitors like it) was that it did monochrome CGA via the 9-pin RGBI port, IE, it took the digital input and rendered it into shades of gray in hardware. The "standard" way to have CGA in monochrome was via a composite cable (at least in the early days, later third-party CGA cards often lacked composite ports) and that produces a far messier display. (Almost unreadable unless you use "mode bw80" to turn off the colorburst signal, which otherwise renders as a mess of extraneous dots.)

 

[Skate323k137]

If you want to see it, I can hook the iigs up to my 800 TVL sony PVM 20M4U, and see what the desktop really looks like on an aperture grille. 

 

[techknight]

I skimmed this thread and tried to catch every detail, but...

if you recapped/rebuilt the monitor and brightness still drifts as it warms up is a sign of a weak CRT. just FYI. 

 

[Skate323k137]

Yeah, I know. I elaborated on that a little bit. I set it to do it's best when it's warm, but I know the tube is old. Always a risk you take I suppose  :/

Perhaps some day I'll find one with a broken chassis, and steal the tube for this guy. 

 

[CC_333]

What size is it? I'm sure there were some contemporary TVs that used that tube (or something sufficiently similar to be compatible).

c

 

[Skate323k137]

12 inch Mitsubishi tube if I'm not mistaken. 

 

[Skate323k137]

I was curious what a trinitron would look like with the desktop pattern. This is the nicest tube I own, PVM 20M4U, which lives in my 2-slot MVS cabinet.

It's cool how on the previous page with the pictures of the original monitor you can see how red and blue especially appear to have different thickness of black border around them, where the PVM is quite consistent thanks to aperture grille. 

 

[CC_333]

Those lines definitely don't look quite as good when one can see them clearly. Usable, but not the most fun to look at for hours.

Makes me think that it was intentional to have the display slightly off. As to why they couldn't have instead used a different pattern and a "normal" monitor, who knows?

c