School me on old-school monitors

[shoestring]

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?

Really nice score.

 

1084 monitors are priced higher because of the Commodore badging. I think most people don't realise what they really are inside.

 

I recently saw 2 x cm8833s for $50 and nobody wanted them. Meanwhile a 1084S was being bid on.

[spacecadet]

Really nice score.

 

1084 monitors are priced higher because of the Commodore badging. I think most people don't realise what they really are inside.

 

I recently saw 2 x cm8833s for $50 and nobody wanted them. Meanwhile a 1084S was being bid on.

 

I could have gotten this CM8505 for $10 if I wasn't in a bidding war with one other guy (only me and him bid). Ended up probably paying a bit too much (I'm slightly embarrassed to say the exact amount, but feel free to search Ebay for closed listings) but still much less than the $200+ most decent 1084's sell for.

 

There is another CM8505 on Ebay right now if anyone wants to try for it - it says local pickup only but I emailed the guy and he sounds willing to ship it but physically unable right now. He told me to hang tight, though, so it sounds like he'll be able to ship it in the near future. His has the covers over the RGB ports, but mine looks like it had those at one point and they just punch out. You could ask him if there are actually ports behind the covers, though.

[shoestring]

At least you know now. These unwanted Philips CRTs are hidden gems.

 

I still have my original 1084S that I used on my Amigas. It has served me well over the 20 years.

 

Nowadays I use it for arcade stuff but I try to avoid using it for the time being after having to replace the flyback and 1 capacitor. Once I recap the entire chassis I'll start using it more.

Edited September 4, 2016 by shoestring

[carlsson]

Yowsa! I knew 1084 monitors had become fashionable, but not $200 fashionable. About 7 years ago, they still were on the verge that you got them for free but times have changed in the 2010's.

[Mitkraft]

Ok, I need somebody to explain this. What is "digital rgb". My understanding is that RGB is an inherently analog format.

[spacecadet]

Yowsa! I knew 1084 monitors had become fashionable, but not $200 fashionable. About 7 years ago, they still were on the verge that you got them for free but times have changed in the 2010's.

 

They seem to sell for less if you wait for the right one, but I got in one of those moods where I decided I *had* to get all my computers that have been sitting around for 20 years up and running like, *this week*. And at the moment, it's not possible to find a decent one for less than $200. In fact there just aren't many even available at all that have the RGB inputs.

 

I am sure it's still possible to get lucky and find one locally for a lot less. Checking the "sold" listings on Ebay, one that was set for local pickup only went for 1 cent... I wonder if that seller went through with that deal. But people do seem to be starting to catch wise and setting their initial prices or BINs higher.

[CRTGAMER]

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.

 

The CGA IBM compatibles will need an adapter to hook up to a VGA monitor.

 

Most older 8 bit and 16 bit computers output composite and or SVideo and can plug into a regular TV, just don't use the RF connection! You just have to find or make an adapter cable to match each proprietary pinout.

[carlsson]

Ok, I need somebody to explain this. What is "digital rgb". My understanding is that RGB is an inherently analog format.

The question was already asked in this thread, and answered on page 1. Digital RGB is also known as RGBI and handles 8 or 16 colours, as opposed to analog RGB that handles as many colours as there are voltage variations within the 0 - 0.7V range the monitor/TV can deduct.

[Osgeld]

The question was already asked in this thread, and answered on page 1. Digital RGB is also known as RGBI and handles 8 or 16 colours, as opposed to analog RGB that handles as many colours as there are voltage variations within the 0 - 0.7V range the monitor/TV can deduct.

 

on older systems this is true, in the modern world (ega and above) its just like the RGB values in your paint program, ie 8 bits red 8 green 8 blue = 24bits ... 2^24th = 16777216 colors

Edited September 5, 2016 by Osgeld

[Nebulon]

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?

Yep. That's the same one I have. I originally purchased it for my Color Computer 3 and then moved it over to the Amiga 500. Great monitor.

[Nebulon]

Yep. That's the same one I have. I originally purchased it for my Color Computer 3 and then moved it over to the Amiga 500. Great monitor.

So just to make sure I looked at my monitor as soon as I got home. It turns out I'm using a Magnavox 8CM515. Darned if it doesn't look exactly like the monitor that you found (including the ports). Now I'm wondering what the differences are...

[spacecadet]

So just to make sure I looked at my monitor as soon as I got home. It turns out I'm using a Magnavox 8CM515. Darned if it doesn't look exactly like the monitor that you found (including the ports). Now I'm wondering what the differences are...

 

That's apparently the RGB Monitor 80, which is the "80 column" version and has better resolution. I might keep hunting around for one of those, because it's probably going to be a lot better experience with any 16 bit computer. But the 40 is working well for me right now.

[carlsson]

Different dot pitches?

 

Edit: I found a CoCo 3 discussion from 1987 where Marty Goodman mentioned that these monitors are not measured by dot pitch, but by stripe width.

 

8CM505 = 0.65 mm stripe width (Monitor 40, the one Spacecadet got)

8CM515 = 0.42 mm (Monitor 80, the one Nebulon got)

8CM562 = 0.42 mm (no analog RGB, may be the same as Commodore 1902A)

8CM643 = 0.37 mm (different Monitor 80, may exist as one or more 1084 models)

Edited September 13, 2016 by carlsson

[Tempest]

Never underestimate the effect of dot pitch. It really can make a difference.

[Nebulon]

This is kind of cool:

http://www.zimmers.net/anonftp/pub/cbm/schematics/monitors/1084P_Service%20Manual_314890-01_(1988_Jul).pdf

 

BTW, if your Magnavox monitor (8CM515 or 8CM643) starts making a high-pitch noise and then the screen goes dead, it can be fixed. I watched a guy flip one on its face, pull the back plastic half of the case off, and high-temperature solder about 6 or 8 points on the circuit board at the very back of the monitor (it's easy to get at). I had one monitor fixed this way and have had no trouble with it since. He apparently did this fix a lot. One caution though is to only do this sort of thing if you're familiar with CRT repair, since there's a lot of electricity packed into those tubes -- even when unplugged..

[spacecadet]

Yeah, you can definitely see the "stripe width" on the Monitor 40. To me it actually looks right for 40 columns and older 8 bit machine graphics, or even text mode on an IBM PC compatible (like my Tandy 1000). Playing games on these machines also gives you that cool old-school aperture grille look that I mentioned in the "Are CRT scanlines important?" thread.

 

But running Deskmate on my Tandy 1000, which is an early attempt at a GUI, does look a little trashy. It's kind of hard on the eyes. Part of that's probably just Deskmate, but it's obvious when you've got the entire screen in static color that there's a lot of empty space in between those phosphors.

 

Still, I like it a lot. But I could see outgrowing it at some point. I'm working on a video about it right now, so maybe you'll see some of what I'm talking about once that's done.