School me on old-school monitors

[spacecadet]

So I've started picking up some vintage computers from my childhood, and while I think I know a decent amount about the computers themselves, I realized a week or so ago that I'm clueless about monitors. I had assumed there was some interoperability and I think there still might be, but I don't really know what to look for as far as connectors, adapters, sync rates, etc.

 

I don't really want to have 10 different CRT monitors around my house (also don't want to spend the money). So what I'm looking for is one monitor that I can use with a C64, a Tandy 1000 (CGA), an IBM PC (CGA) and an Atari XL at least, possibly a TI-99/4A as well. Is there such a thing? What am I looking for? I have an AppleColor RGB monitor for my Apple IIGS but it has only 8 pins; the Tandy has 9, and the C64 has a DIN connector. But is there some way to adapt it?

 

I guess ideally I'd love for this possibly mythical monitor to match one of the systems I have (those listed above), rather than being a third-party manufacturer.

 

I know a TV would work for at least a couple of these systems, but the Tandy 1000RL/HD that I have doesn't seem to have an RF output, and anyway I'd rather use a proper monitor for clarity, if I can.

 

Thanks for any help.

Edited August 12, 2016 by spacecadet

[rpiguy9907]

You want a Commodore 1902, 1084 or comparable Magnavox or Phillips monitor. The key is to support Digital RGB and S-Video (Chroma/Luma). Some professional Sony monitors will do this as well. And of course a lot of cables!

 

The Apple RGB monitor is analog RGB only. The Commodore 1084 is analog RGB but has toggles for digital and Svideo/composite.

[rpiguy9907]

Just to spell it out more clearly:

 

Digital RGB is for the CGA/Tandy

Chroma/Luma/S-Video is for the Commodore 64 (and some Atari 8-bits)

Composite is for 99/4 and Apple II (and the rest of the Atari 8-bits)

 

The Commodore 1902 will handle all those. The 1084s add analog RGB and can also be used with Amigas, Apple IIgs, and Atari ST if you have he correct cables.

[spacecadet]

Thanks for the help, that really gives me a pretty clear direction of what to look for.

 

On the one hand it kinda kills me, though, because attached is the Amiga setup I sold a while back (to buy my IIGS)...

 

 

That thing was the yellowest computer I've ever seen, but I sure wish I'd kept that monitor now.

 

[rpiguy9907]

There is an Amiga 500 for sale near by that is practically orange! Something about Amiga plastics.

[Osgeld]

Yea apples are bad about it too its how much fire retardant they put in them

 

Vs cases with more metal inside

[eightbit]

I always preferred the Commodore monitors. My personal favorite was the 1084S (the "S" was for "stereo"). It served as my game monitor, computer monitor and TV set for years

[Seob]

Philips model number would-be cm8833 ie cm8833-ii. Magnavox i think color monitor 40

[spacecadet]

Ok, I'm about to lose an auction on a Magnavox Model 40 that I thought I had in the bag. (Shakes fist) I guess there's another guy just like me out there but with a lot more money.

 

Commodore monitors seem to go for even more outrageous prices, I'm guessing because people know how versatile they are.

 

My new question is, is there any sort of adapter that would let me use all these computers with a standard VGA monitor? Something like this? https://www.amazon.com/Arcade-video-converter-board-output/dp/B00E7HOFOO/ref=as_li_ss_tl?ie=UTF8&linkCode=ll1&tag=atariage&linkId=faac553b09df3a0ea0413014c0401cf2

 

I have an old VGA monitor sitting up in the attic. Or at worst, I guess I could use a CGA monitor or VGA monitor with converter for the CGA computers, and an old small TV set for everything else.

[BillyHW]

There was a digital RGB? Learn something new every day...

[carlsson]

That kind of RGB to VGA adapter will work, but beware of lag due to delays to convert the signal. I had a GB82xx one a couple of years ago, but found it had unbearable lag so I traded it to a friend. It is possible that firmware and/or hardware has improved so it is less of a problem, or that there are other similar devices at higher price that do the job better.

 

As far as I know, that type of board doesn't easily work with composite or S-Video due to the nature of those signals is different from CGA. There are other type of converters for those signals though, again with caveat about lag, scaling, blurryness or whatever.

 

Digital RGB = RGBI = CGA = 3.3 - 5V signal levels = What C128, BBC Micro and plenty of other systems offered

Analog RGB = 0.7 - 1V signal levels = What many other systems used

 

You can build a voltage divider out of a handful of resistors to convert digital RGB to analog if required. It is not rocket science, but if you want the ultimate colours and saturation, the science may lay in exactly which resistors to use depending on which levels the device outputs in the first place.

[Osgeld]

There was a digital RGB? Learn something new every day...

yep, CGA (4 bit) and EGA (6 bit) are both digital, and all LCD interfaces (8 - 24 bit) are digital RGB

[spacecadet]

Just to update this, I just won the Magnavox CM8505 I mentioned losing earlier... it was relisted. Paid a little more than I wanted to, but still got it for less than a well-worn 1084 and it's supposedly new/unused and in the box. Now to just track down some cables...

Edited September 1, 2016 by spacecadet

[rpiguy9907]

Congrats! But I am afraid you were steered in the wrong direction by Seob. The Color Monitor 40 has neither digital nor analog RGB nor S-Video. It is essentially a composite monitor :-(

Edited September 2, 2016 by rpiguy9907

[rpiguy9907]

Congrats! But I am afraid you were steered in the wrong direction by Seob. The Color Monitor 40 has neither digital nor analog RGB nor S-Video. It is essentially a composite monitor :-(

[Tempest]

One thing to look out for on CGA monitors is whether or not they support color 6 as being brown or 'dark yellow'. IBM added some circuitry to its monitors to make this ugly yellow color a nice tan brown (most games expected this), but not all monitors do this.

 

https://en.m.wikipedia.org/wiki/Color_Graphics_Adapter

[spacecadet]

Congrats! But I am afraid you were steered in the wrong direction by Seob. The Color Monitor 40 has neither digital nor analog RGB nor S-Video. It is essentially a composite monitor :-(

 

Well, if that's the case I'll just resell it again. It wasn't just Seob, though - I did some crosschecks elsewhere, for example: http://gona.mactar.hu/Commodore/monitor/Commodore_monitors_by_model_number.html

 

which shows the service manual being for the 1084 and CM8505 (among others). Then this thread: http://amigaworld.net/modules/newbb/viewtopic.php?topic_id=36807&forum=25

 

where one guy says the CM8505 is just a rebadged 1084 and is never corrected.

 

And this single post: http://www.uncreativelabs.net/phpBB2/viewtopic.php?t=201&sid=c757f72b67c88ccac70d34f36eb61822

 

where the guy says the CM8505 (along with a CM8674) has two round "keyboard-like" connectors, which should be the RGB connectors.

 

The back of the CM8505 definitely has the *cutouts* for the RGB connectors, and even has them labeled as such, but they're covered in such a way that I couldn't tell in any of the few pics I could find whether you could just pop the covers out or if they were permanent. But all the other evidence I was finding online suggested the connectors were actually there, under the covers.

 

If not, then c'est la vie. I will sell it again. I'll find out on Saturday, I guess.

Edited September 2, 2016 by spacecadet

[shoestring]

The 1084S-P1 or P2 are rebranded Philips CM8833-II. These variations ( and there were many ) were actually made by Philips for Commodore.

 

Great monitors but the Philips is slightly better, they kept the better tubes for themselves.

[carlsson]

As you might know, the 1084 series involved a number of monitors from different manufacturers, with varying inputs and specs. I think it is more safe to go on Philips/Magnavox model numbers and correlate those to specific models of the 1084, than the other way around. It was not uncommon to see 1084's with cutouts for connectors, but nothing inside, in a way to use the same shell for all monitors independent of the hardware inside.

[shoestring]

Some really good info here.

 

http://gona.mactar.hu/Commodore/monitor/Commodore_monitors_by_model_number.html

[carlsson]

It is remarkable how many of those models are repackaged Daewoo models. At least over here, Daewoo was and still is (in case you find anything at all) a true budget brand, something you might buy for your 8 year old to have a TV or stereo but not something you would seek after as a fine piece of equipment that you still 25+ years later would pay a bit extra for.

 

Actually a few years ago I picked up a 14" Kendo TV at the goodwill store for ~$6 that appears to exist under multiple equal lower end brands. It just has a single SCART input, but honestly it produces a RGB image with my Amiga that is nearly equal to what either of my two 1084's can display. This is not true for every 14" that I've tested though, so YMMV more than ever, just that even noname brands sometimes may have unexpected qualities.

[rpiguy9907]

Spacecadet please update is with what you have found. I went to my local electronics surplus in Pottstown and they had a Magnavox Color 40 ($25) as well a Color 80 ($35). One thing I noticed, the Color 40 appears to be missing the toggles to switch between inputs. If you do uncover RGB ports and they work please let us know how the monitor switches between inputs.

[spacecadet]

Ok! I got the monitor and it is exactly as I hoped. It has both RGB types in addition to composite.

I knew it didn't have s-video, but that's ok - the C64 is the only computer I have (and likely will ever have) that supports that, and I know from experience selling TV's back in the day that composite *can* look better or worse depending on the tube and comb filter, and this monitor seems to have a good comb filter. I didn't see any dot crawl or moire. (My camera did when I tried to take photos of it in action, but I didn't with my naked eye.)

 

As a bonus, it came with a C64 cable, and the monitor does work and looks great. I haven't been able to test RGB/CGA yet because I need to order the cable - I was waiting to make sure the monitor had that before I did so.

 

I think the confusion about this monitor may be because it seems like there are actually two different "Monitor 40's" - I'm pretty sure I've seen a "Color" Monitor 40 in addition to this "RGB" Monitor 40. I didn't really pay that much attention to the names, I just went by the model number of CM8505, which everything else on the internet said had both digital and analog RGB just like the 1084. Kind of a pain that it's a DIN plug but I found at least one site that has those cables for cheap.

 

Anyway, thanks for everyone's help - I wouldn't have even known this monitor existed before starting this thread, and it was a lot more reasonably priced than any 1084 I found. And all I'm missing out on is s-video.

 

Edit: to answer the Q above (or not answer, more accurately), I am not sure how it switches. Under the front door there is one switch that says "CVBS/RGB", which I assume switches between composite and RGB, but there's no obvious switch I can see for the different RGB inputs. So I'm not sure what it does. Maybe it just detects whichever is active?

Edited September 3, 2016 by spacecadet

[Osgeld]

It is remarkable how many of those models are repackaged Daewoo models. At least over here, Daewoo was and still is (in case you find anything at all) a true budget brand, something you might buy for your 8 year old to have a TV or stereo but not something you would seek after as a fine piece of equipment that you still 25+ years later would pay a bit extra for.

 

Actually a few years ago I picked up a 14" Kendo TV at the goodwill store for ~$6 that appears to exist under multiple equal lower end brands. It just has a single SCART input, but honestly it produces a RGB image with my Amiga that is nearly equal to what either of my two 1084's can display. This is not true for every 14" that I've tested though, so YMMV more than ever, just that even noname brands sometimes may have unexpected qualities.

 

My mother won a 13 inch Daewoo TV back when 13 inch TV's still cost money, its still at their house and yea its built like a lean to, its remote is junk, its CRT is actually very nice, and it rivals their flat dunno 19 inch trinatron CRT quite easily

[rpiguy9907]

Ok! I got the monitor and it is exactly as I hoped. It has both RGB types in addition to composite.

 

I knew it didn't have s-video, but that's ok - the C64 is the only computer I have (and likely will ever have) that supports that, and I know from experience selling TV's back in the day that composite *can* look better or worse depending on the tube and comb filter, and this monitor seems to have a good comb filter. I didn't see any dot crawl or moire. (My camera did when I tried to take photos of it in action, but I didn't with my naked eye.)

 

As a bonus, it came with a C64 cable, and the monitor does work and looks great. I haven't been able to test RGB/CGA yet because I need to order the cable - I was waiting to make sure the monitor had that before I did so.

 

I think the confusion about this monitor may be because it seems like there are actually two different "Monitor 40's" - I'm pretty sure I've seen a "Color" Monitor 40 in addition to this "RGB" Monitor 40. I didn't really pay that much attention to the names, I just went by the model number of CM8505, which everything else on the internet said had both digital and analog RGB just like the 1084. Kind of a pain that it's a DIN plug but I found at least one site that has those cables for cheap.

 

Anyway, thanks for everyone's help - I wouldn't have even known this monitor existed before starting this thread, and it was a lot more reasonably priced than any 1084 I found. And all I'm missing out on is s-video.

 

Edit: to answer the Q above (or not answer, more accurately), I am not sure how it switches. Under the front door there is one switch that says "CVBS/RGB", which I assume switches between composite and RGB, but there's no obvious switch I can see for the different RGB inputs. So I'm not sure what it does. Maybe it just detects whichever is active?

Makes sense! Awesome find and great to know for the future. Thanks for the update.