Need advice on software for a Macintosh LC original

[Verault]

OK so some news. The VRAM wasn't entirely the issue. I decided to try out the stock monitor I have instead of the adapter. Its a 12" RGB model M1296. I booted the LC up with the 512KB VRAM stick and the display is crazy!!! see photos 1 and 2. The weird thing is the ghosting and patterns but you will see not only do I have 256 color mode, but it lists THOUSANDS AS WELL! (sorry forgot to take a photo of the thouands option, just trust me itss there with the 512KB VRAM. Also the crazy video is in any color/video mode.. black and white looks messed up too. My question is this, is the 512KB in VRAM trying to bump up to a resolution that this M1296 monitor cannot do or is the 512KB VRAM bad?

I took out the 512KB VRAM and put the stock 256KB in and wouldn't you know, it gives the option to 256 colors! ( see photo 4) Don't know why it didnt give that option on the LCD screen with video adapter,,, but it didn't. So at the very least I can use a 256KB vram with this monitor to get 256 colors. But regardless since I have other LC's I want to know what the deal is with the crazy video and the 512KB VRAM module.

 

[cheesestraws]

Don't know why it didnt give that option on the LCD screen with video adapter,,, but it didn't

This is all about the amount of memory used by the screen and the screen resolution.  If you have more pixels on the screen, then there's less memory available per pixel.  Here's roughly how it works out in your case:

• The 12" RGB display you have has a fixed resolution of 512x384.  256 colours requires one byte per pixel.  So, 512 x 384 x 1 = 196608 bytes, which is less than 256k, so it will fit into 256k of VRAM, so you can use that screen mode.
  
• But! 512x384 isn't a standard VGAish resolution.  So I bet you that your LCD was doing 640x480, instead.  If you do the same calculation, 640 x 480 x 1 = 307200, which is more than 256k.  So that won't fit into 256k of VRAM, so you can't use it.
  
• When you put 512k in, you can do a similar calculation.  Thousands of colours is 2 bytes per pixel.  So, 512 x 384 x 2 = 393216, which is less than 512k, so you can do 512x384 at thousands of colours with 512k of VRAM.  But you can't do 640x480 at thousands of colours, because 640 x 480 x 2 = 614400, which is more than 512k.
  

I realise that's a bit of a barrage of arithmetic, but I hope it vaguely helps.  The thing to remember is that you have to keep track of what colour every single pixel is in VRAM, so the more pixels you have, the less information you can store about each, which means fewer colours.

But regardless since I have other LC's I want to know what the deal is with the crazy video

I'll have to defer to someone else who knows more about this.  How does your 512k behave with an adapter/LCD?

 

[Verault]

I get the long and short of it I suppose. I get why the adapter to lcd wasnt working, but I still dont know why the 512KB VRAM isnt working. I only have this monitor and a IIGs monitor which wont work on anything but a IIGS

Ya know I didnt try the 512kb vram on the lcd with adapter. Il ldo that now.

Nope, you can tell the monitor is getting some kind of signal because the light is one but its all black.

BTW here is the photo of the M1296 Monitor with the 512kb vram showing thousands of colors.

EDIT: Are there diagnostics I can download and run on the LCo determine if the vram is faulty?

 

[Verault]

Noone has any input on what the problem is on my LC?

 

[Unknown_K]

I snagged an original LC with dual floppy drives for OS 6.x. Only other LCs I bother with are LC3's with 7.1 and HDs of course. 

 

[sstaylor]

I would guess that your monitor is desperately out of adjustment; it looks like the electron guns are far out of alignment.  I don't recall off the top of my head, but it seems like they are adjusted on the neck of the crt which is really difficult.  It might adjust by way of pots on the inside which is somewhat easier but still tough.

There are copies of the service manual around and you might check one of those for instructions.

 

[Verault]

Sorry SStaylor its not the CRT. IF you scroll up to a previous post you see that if I have a 256KB vram module I get 256 colors available and everything looks fine. IF I use a 512KB vram module I get thousands of colors as an option but the image has doubling and looks all messed up.

 

[Verault]

I snagged an original LC with dual floppy drives for OS 6.x. Only other LCs I bother with are LC3's with 7.1 and HDs of course. 

Two floppies? I think that was the budget model only availables to schools and universities. I have 3 original lcs. One has a bad logic board and 2 have bad hard disks. I have an lC III thst works but the cas are leaky and i need to grt around to replacing them. I recently restored a IIci. Even it has a faster cpu similar to the LC III. I just need a portrait video card so i can use my portrait monitor.

 

[Unknown_K]

I could be wrong but the cases have a removable plug on the LC1 so you can install a second floppy instead of the HD. Anyway I just wanted one because it was different.

LC3's are easy to recap, I have a spare motherboard I redid and forgot where I put it since I installed a 68040 board into the case.

 

[Verault]

I could be wrong but the cases have a removable plug on the LC1 so you can install a second floppy instead of the HD. Anyway I just wanted one because it was different.

LC3's are easy to recap, I have a spare motherboard I redid and forgot where I put it since I installed a 68040 board into the case.

I saw a couple images about thr 68040 upgrade boards. One company was PSI ithink but i couldnt find much info on it. Since they have prettyy similar boards would thr cpu board work on the original LC since it would benefit the most? And yes the LC, LC II, and LC III all have that removeable slot. I just thought they were for the apple IIe card and network controller cards until i found the processor card i mentioned.

 

[Verault]

You know I wonder if that vram (512KB module) came from my LC III. I wonder if it will have different results with the same monitor running on the LCIII.

 

[dan.dem]

Many questions have already been answered, as an original LC owner I want - in good old usenet style - to sum up some findings and add my own experiences:

1. Mac System 6 and 7 offer system specific installations especially for the LC, taking also care for its video circuitry. You should use these or probably the "universal Install" ("for all Macintoshes") settings of the Mac System Installer. The original LC (with MC68020) is compatible with versions 6.0.6 to 7.5.5.

2. The LC comes originally with one VRAM SIMM of 256kB in a single VRAM socket (next to the RAM sockets). This may be exchanged for a 512 kB VRAM SIMM (I did this in on my system in 1992).

3. With 256kB VRAM you get 256 colors/grays on Apple's 12 inch RGB Monitor, giving a screen resolution of 512 x 384 pixels, or 560 x 384 with the Apple II card (and with some system or monitor cdev versions, can't remember any more). You get 16 colors/grays with Apple's 13" High Resolution or Apple's later 14" displays, all at 640 x 480 pixels. Note, these are not VGA displays (different horizontal and vertical frequency). You get the same 640 x 480 pixels at 16 colors/grays on real VGA displays.

4. Original Apple Monitors are signaling their type by the so called "sense pins" in the display connector. If you are using a non-Apple monitor you need an adapter which usually includes dip switches, allowing you to configure the sense pins according to your needs. Note, that the later popular Multisync setting may likely not work with LC. You have to go for true VGA or simulating an Apple 13/14 inch (need to look up correct timing and sense pin-settings).

5. If you exchange the original 256 kB VRAM for a 512 kB one, you get "Thousands" of colors on the Apple 12" display and 256 colors/grays on 640 x 480 (both Apple 13/14" or real VGA). Everything about sense pin settings apply here as well.

Also: A analogue CRT monitor doesn't have an electrical limit in the numbers of colors it can display, it solely depends on the computer video hard- and software.

If your system software is correctly installed (preferably from a booted installer medium), and your video adapter/cable is correctly configured (you need to consult your adapter's configuration instructions or try through all possible settings) and you still have video issues the VRAM SIMM may be damaged.

More options for transferring software: If your source computer can handle 1.44 MB floppy disks (Mac or PC) you can use these on the LC too. To access DOS-formatted floppies (or even hard disks) comfortably you need a cdev from System 7.5 "PC Exchange", this may run also on 7.1 (not sure). For older Systems there was also the third party (Insignia Solutions or so) cdev "Access PC" which worked similar and probably even with System 6. However I have a faint memory of a system utility which shipped originally with "Super Drive" equipped Macs (1,44 MB types) which could be used too. To avoid problems with the resource fork of Mac software it is preferable to compress it with older versions of StuffIt or CompactPro (or encode the software to binhex-format). You need to unstuff/uncompress/unbinhex your compressed/encoded files on the LC.

Other transfer options are modem or network (even using ftp on a MacTCP-equipped LC - I had to fall back to this in University), but I don't want to discuss this in detail since this is already a very long post.

Games: You may want to look for newer versions of old Mac games. Old versions originally been written for 1-bit video on non-multifinder systems are often not compatible with newer video hardware, multi-color systems, Multi-Finder or System 7. (Re-) Releases from 1991 to 1993 may work most likely. Some games need 640x480 screens, some need 8-bit video (256 colors/grays), however many offer 4 bit (16 colors/grays) or even 1-bit (monochrome) versions.

 

[Verault]

I appreciate the response Dan.Dem but I don't think that does address the question of why the 512KB vram stick renders those display issues on the M1296 Monitor. The LCD panel and adapter aren't even being used. This is an M1296 monitor and an LC with 512KB vram installed.

Since I only have one 512KB vram stick and it has these issues I have no idea of whether or not its the Vram or the something else. All I know is the several 256KB vram simms I have work fine.

 

[Nathan]

This is complete conjecture, but maybe it's a timing issue/mismatch of some kind?

The LCIII is a third again as fast as an LC/LC II (16 MHz vs 25 MHz). So the VRAM stick would have had to be spec'd in a way that can keep up with the faster cpu/system. Suppose that the machine must clear old VRAM in addition to writing new VRAM. If those two things don't happen quickly enough there might be some ghosting as some information lingers long enough to be seen in multiple 'frames'.

Although it's weird that you have afterimages that are oddly placed left/right and/or up/down of the 'actual' image which might lead one to thinking that horizontal/vertical synchronization is also fishy.  Maybe it's not rendering the image in exactly the same spot each time?

P.S.  

If the LCIII you borrowed the VRAM from works, maybe test it with it's "original" VRAM on this particular monitor and see what happens?

 

[Verault]

Thats not a bad theory. I guess its worth a test.

 

[dan.dem]

I don't know about the specs of the LCs VRAM SIMMs, but I wouldn't expect that a 512k from a LC III or later would work on an LC/LCII.

Back in the early 1990s I bought a specific LC 512 kB VRAM SIMM and it works, giving 256 colors/grays on 640x480 or "Thousands" on 512/560x384.

The video on LCs is connected by a slow/narrow bus (16 bit SE-style, I guess). I am quite sure LCI/II and LCIII/IV do not have the same VRAM speed. It is a common misconception that faster chips work well in slower circuits. This is generally not the case, since they have optimized "phase delay times" (not sure I translated this term correctly, in German it's "Phasenlaufzeit") for their operating speeds.

BTW, VRAM-SIMMs are not of the 72-pin SIMM type like the main systems RAM in the LC III/IV.

About monitors: If an analogue RGB monitor, like the Apple 12" RGB you used, works with a certain resolution and refresh rate it will work independently of the color depth. The analogue transmitted signals are just the same, only the signal levels have coarser or finer steps. So, your 12 inch Apple RGB display is most likely good. And, as I wrote in my previous posting, the sense pins in the monitor connector or adapter (here controlled by the dip-switches) are telling your Mac what resolution and refresh rate the monitor expects. Note that there are different refresh rates for the 640x480 format (Apple 75 Hz, original VGA 60 Hz). Again, this has nothing to do with the screen depth on analogue signals.

 

[dan.dem]

... Note that there are different refresh rates for the 640x480 format (Apple 75 Hz, original VGA 60 Hz).

I have to correct myself. Memory tends to make the past better then it was. For example here the refresh rate of the original Apple High-Resolution RGB Monitor and related displays at 640x480. The original specs sheet reads:

Scan rates: 35.0 kilohertz horizontal, 66.7 hertz vertical

Original VGA is 60 Hz (hertz) as stated, some not so early devices may support higher scan/refresh rates.

Again, sorry for the error.