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Strange board on Mac 512k
- Thread starter Jelly
- Start date
I disagree on the prototype idea, its probably just a limited production board made by a upstart
it could also hook up to the apple //c style monitors they used a combination of different signals on a 9 pin output including ntsc and more or less serial in the same plug, which included a what ? 10-12 inch "rgb" (which is total apple marketing crap in its glory days, if you look at a //c pinout) color monitor
it could also hook up to the apple //c style monitors they used a combination of different signals on a 9 pin output including ntsc and more or less serial in the same plug, which included a what ? 10-12 inch "rgb" (which is total apple marketing crap in its glory days, if you look at a //c pinout) color monitor
Mac128
Well-known member
And, European sets run at 100 or 200hz being an exact multiple of 25, while 600hz sets (more common in Europe) are multiples of 24, 25 & 30. Only NTSC's 29.97 frame rate will not resolve natively. Moreover, any 24 frame film edited on video under ATSC will have already undergone a 3:2 pulldown introducing judder. Under the PAL system, that was never an issue as the frame rate was merely sped up imperceptibly.
Mac128
Well-known member
Wow, I think you are absolutely right. So here's the question ... why such a huge board for a simple TTL adapter? Pina shows how to construct one in his book that consists of a single chip on a tiny board. What exactly is this board doing then? That giant capacitor alone has me stumped.
Here's a question, what if that isn't audio at all? What if it is a composite video output, that would certainly explain the additional chips if it was converting to NTSC or PAL. Albeit I am stumped as to why it would be split unless it was used to drive more than one monitor. I can't tell from the picture how far up the cable the split occurs. But seriously why would a board of this nature need to provide a separate sound output? The Mac already had a decent sound output. Just pass the sound through this board and take it off the jack – one less wire to run out of the case. Unless the board modified the sound in some respect, but I'm not sure how as there's no way to control it. I suppose it could drive sound off the Mac without bypassing the Mac's built-in speaker which plugging into the audio jack would do.
Let's flip it around ... what kind of inputs could a card like that provide for the Mac? It's situated between the logic board and analogue board, so at best it could allow the Mac to act as a monitor and speaker, but it couldn't send anything to the logicboard, so no data. But who would want such a thing? Perhaps a way to switch between an Apple II or a PC using the Mac as the display? But who would want a 9" B&W monitor when they could go the other way and have a larger color monitor?
Osgeld has a point too, that there could be an NTSC or PAL signal coming off the 9 pin connector like the Apple IIc & IIGS, but the Apple IIc/IIGS used a standard 15-pin connector, so if that's the case here, it would be some unique custom adapter, long since gone, and not compatible with anything Apple sold. Did the PC world use anything like this as a video output standard interface?
I also agree with Osgeld, it looks like a startup company, limited run kind of thing, not quite as crude as some prototypes I have seen. The 11-pin connector is a good indicator. I wouldn't expect a prototype to use such a finished power connector cable.
I have another question which is whether NTSC or PAL would use more or less circuitry, or about the same?
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H3NRY
Well-known member
About the same. In either case, or the case of driving a CGA monitor, the scan rate has to be changed from 26 KHz (IIRC) to 15.75 or 15.62 KHz, so there has to be a frame buffer (RAM), and circuitry to deserialize the Mac video and stuff it into RAM, and circuitry to reserialize the RAM data into a new video stream.
Trash80toHP_Mini
NIGHT STALKER
Has anyone done any analysis of the individual ICs as yet? I haven't had a chance to check out the new pics on a big monitor.
I had a NewLife Accelerator for the Compacts (in a 512k with a cheap 128k MoBo substitute cuz I was too chicken to solder a standard socket to my un-Killy Clippable Proc) that was supposed to do video out to a TTL Monitor. I don't think they released software that enabled it to function before they went belly-up, the stuff that came with the card didn't work.
I can't see anyone doing CGA out of a Mac, there's better resolution on the 9" CRT inside the box and no real color capability on the MoBo. Hercules Graphics level output to a TTL Monitor would make a LOT more sense to me for a card like this. More pixels on a larger TTL Monitor was the reason I bought that NewLife Card back in the day!
As for the prototype WAG, I'll grant you it must have been a VERY short production run, because that board has just aweful "production value" the way it stands. It looks like it'd be a freakin' radio frequency noise transmission unit/antenna plugged inside of your Mac!
I had a NewLife Accelerator for the Compacts (in a 512k with a cheap 128k MoBo substitute cuz I was too chicken to solder a standard socket to my un-Killy Clippable Proc) that was supposed to do video out to a TTL Monitor. I don't think they released software that enabled it to function before they went belly-up, the stuff that came with the card didn't work.
I can't see anyone doing CGA out of a Mac, there's better resolution on the 9" CRT inside the box and no real color capability on the MoBo. Hercules Graphics level output to a TTL Monitor would make a LOT more sense to me for a card like this. More pixels on a larger TTL Monitor was the reason I bought that NewLife Card back in the day!
As for the prototype WAG, I'll grant you it must have been a VERY short production run, because that board has just aweful "production value" the way it stands. It looks like it'd be a freakin' radio frequency noise transmission unit/antenna plugged inside of your Mac!
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dunno, the images are gone, but when I looked there was a ton of 74x logic series chips, which can be configured for anything
and for the time its quality isnt that much better than most commercial items, and since its almost all ttl (which has nothing to do with its output, I am using ttl 74x logic series to drive a low rez vga signal ... sorta its in the works) it wont effect much of anything in terms of rf (altho it may cause the puny power supply to pulse)
probably the only way to figure this out without having someone that knows is to hook up its output to a scope and see whats being sent
and for the time its quality isnt that much better than most commercial items, and since its almost all ttl (which has nothing to do with its output, I am using ttl 74x logic series to drive a low rez vga signal ... sorta its in the works) it wont effect much of anything in terms of rf (altho it may cause the puny power supply to pulse)
probably the only way to figure this out without having someone that knows is to hook up its output to a scope and see whats being sent
Hi Osgeld,
Nope, the images are still here: http://img638.imageshack.us/g/img8261r.jpg/
I thought a few days ago: let's ask my dummie-question at the liberation forum, they will be able to explain to me in simple enlish what it is I found on my 512k... but your inputs are close to abracadabra to me with abbreviations like TTL, IIRC and so on. But don't mind my 'noob-ism', I will ask a new explanation once you guys agree on the case first. Keep the discussion alive. I have never started a discussion anywhere that made it to a second page ;-)
Someone said earlier that the power cable was strangely connected to the board, and later another guy said that it was nothing more, nothing less than the usual power/data cable for a Mac 512 logic board, but now necessary to connect the alien board. That is correct. For my own convenience I connected the two connectors on the board, for communication I had better not done so.
About the NTSC/PAL discussion: it is and is not off topic. I was my fault in fact, by commenting on the matter that I started this bragging about 'another ancient technology' and I must admit, that in the time I worked with some PALevangelists, they always picked on the USA with lousy NTSC quality, complaining that they were not compatible and so on. My judgement was coloured without me knowing all the ins and outs. Since we all have fancy plasma these days, HD is the way to go...
Next I must compliment all of you for using beautiful english styles, pointy and sharp but always with respect and the right tone. My native language in dutch but I always try to make an effort in using proper english. I got to learn some new thing here already. Another reason (next to the techie side) for me to visit this forum every now and then.
Having all this said, please call on me if there is anything in detail you need to identify this board. Please do not ask me to connect it to the 512 because I can't get it running, I do not have an external monitor to test it and all the audio equipment I have here is a Mac for downloading and an iPod for playing music.
Jelle
Nope, the images are still here: http://img638.imageshack.us/g/img8261r.jpg/
I thought a few days ago: let's ask my dummie-question at the liberation forum, they will be able to explain to me in simple enlish what it is I found on my 512k... but your inputs are close to abracadabra to me with abbreviations like TTL, IIRC and so on. But don't mind my 'noob-ism', I will ask a new explanation once you guys agree on the case first. Keep the discussion alive. I have never started a discussion anywhere that made it to a second page ;-)
Someone said earlier that the power cable was strangely connected to the board, and later another guy said that it was nothing more, nothing less than the usual power/data cable for a Mac 512 logic board, but now necessary to connect the alien board. That is correct. For my own convenience I connected the two connectors on the board, for communication I had better not done so.
About the NTSC/PAL discussion: it is and is not off topic. I was my fault in fact, by commenting on the matter that I started this bragging about 'another ancient technology' and I must admit, that in the time I worked with some PALevangelists, they always picked on the USA with lousy NTSC quality, complaining that they were not compatible and so on. My judgement was coloured without me knowing all the ins and outs. Since we all have fancy plasma these days, HD is the way to go...
Next I must compliment all of you for using beautiful english styles, pointy and sharp but always with respect and the right tone. My native language in dutch but I always try to make an effort in using proper english. I got to learn some new thing here already. Another reason (next to the techie side) for me to visit this forum every now and then.
Having all this said, please call on me if there is anything in detail you need to identify this board. Please do not ask me to connect it to the 512 because I can't get it running, I do not have an external monitor to test it and all the audio equipment I have here is a Mac for downloading and an iPod for playing music.
Jelle
Trash80toHP_Mini
NIGHT STALKER
Thanks for the compliments!
I can help with explaining:
TTL = Transistor to Transistor Logic
IC= Integrated Circuit = Chip (more or less in a loose translation) = simple form of electronic building blocks
Being European, you might have had a Logic Class at some point, in the US they've substituted a course in Euclidean Geometry at the High School level for Traditional Logic in the curriculum.
The most simple TTL chip I saw on your board in a quick viewing was a 7408 with some "abracadabra" thrown into the name.
It's actually four simple logical operation circuits made of transistors that can be used, individually, tied together with traces (printed circuit board "wires") or in combinations with other Chips to create a more complicated logical operator.
The logical operation of all four circuits on this chip is "AND":
each consists of two input connections and one output connection.
IF either input is A (called Low) THEN the output is A low, so:
IF input 1 is A AND input 2 is neutral THEN output = A Low
IF input 1 is neutral AND input 2 is A THEN output = A Low
IFboth inputs are B (called high) THEN the output is B high,
Sorry, that's the best I can do in the time available, I hope I got it right. Gotta run!
I can help with explaining:
TTL = Transistor to Transistor Logic
IC= Integrated Circuit = Chip (more or less in a loose translation) = simple form of electronic building blocks
Being European, you might have had a Logic Class at some point, in the US they've substituted a course in Euclidean Geometry at the High School level for Traditional Logic in the curriculum.
The most simple TTL chip I saw on your board in a quick viewing was a 7408 with some "abracadabra" thrown into the name.
It's actually four simple logical operation circuits made of transistors that can be used, individually, tied together with traces (printed circuit board "wires") or in combinations with other Chips to create a more complicated logical operator.
The logical operation of all four circuits on this chip is "AND":
each consists of two input connections and one output connection.
IF either input is A (called Low) THEN the output is A low, so:
IF input 1 is A AND input 2 is neutral THEN output = A Low
IF input 1 is neutral AND input 2 is A THEN output = A Low
IFboth inputs are B (called high) THEN the output is B high,
Sorry, that's the best I can do in the time available, I hope I got it right. Gotta run!
Mac128
Well-known member
I'd be interested in a better picture of those chips along the bottom of the board. The only picture I could find showed just the corner of the chips which looked like some kind of Kyocera "KM41..." and below it "513..." they look like a RAM array which would fit with what H3NRY indicated was needed for a signal converter.
I wonder why the 512K won't start up with the board. Could it be a failed component, or might the board require special startup software? What exactly happens when you try to start up with the board in? Do you get a bong? Do you get a flashing question mark, or just a black screen?
I wonder why the 512K won't start up with the board. Could it be a failed component, or might the board require special startup software? What exactly happens when you try to start up with the board in? Do you get a bong? Do you get a flashing question mark, or just a black screen?
I will make new pictures, with more detail of the chips you mention.
If I connect the board to the 512, I get a bong and a black screen. No effort is made by the Mac to start from a floppy. Since I have not found the time to try to make a good startup floppy, I have not seen the Mac boot completely. However, without the alien board, the Mac gives the blinking disc icon and you can hear it scan the (faulty) floppy.
Jelle
If I connect the board to the 512, I get a bong and a black screen. No effort is made by the Mac to start from a floppy. Since I have not found the time to try to make a good startup floppy, I have not seen the Mac boot completely. However, without the alien board, the Mac gives the blinking disc icon and you can hear it scan the (faulty) floppy.
Jelle
Charlieman
Well-known member
There are close to 40 ICs on that board. An NTSC or PAL conversion board typically has three logic chips. There's a bank of eight pc74hct161p (MOSFETs?) and an unidentified bank of four similar looking ICs.
This is a very unusual board. The production values look fine to me, based on what was around in the 1980s. My guess is that it is some kind of multimedia output device like the Beck Chromatron that generated a colour signal from the MacPain pallete.
This is a very unusual board. The production values look fine to me, based on what was around in the 1980s. My guess is that it is some kind of multimedia output device like the Beck Chromatron that generated a colour signal from the MacPain pallete.
Trash80toHP_Mini
NIGHT STALKER
I had a thought about this in the shower yesterday!
My buddies at Tekserve got their start in Macs by building the (Mac controlled) Directory Systems for the Rockefeller Center (yes the place with the ice rink!) Office Retail/Space in NYC. This might be a similar board for some kind of Video Based Display. In that case a Color Lookup Table would substitute for the, then unavailable, Color Macs/Toolbox routines. Sound and an external Graphics Output System, TTL or CGA, would make a world of sense. That would easily explain all the extra logic on board. Coupled with the RS-422 Connections, you could do a LOT with a Mac in any Graphics based Display, Signage, Directory, etc.
Dunno, that's just a WAG! :-/
My buddies at Tekserve got their start in Macs by building the (Mac controlled) Directory Systems for the Rockefeller Center (yes the place with the ice rink!) Office Retail/Space in NYC. This might be a similar board for some kind of Video Based Display. In that case a Color Lookup Table would substitute for the, then unavailable, Color Macs/Toolbox routines. Sound and an external Graphics Output System, TTL or CGA, would make a world of sense. That would easily explain all the extra logic on board. Coupled with the RS-422 Connections, you could do a LOT with a Mac in any Graphics based Display, Signage, Directory, etc.
Dunno, that's just a WAG! :-/
Trash80toHP_Mini
NIGHT STALKER
Touch Screen or button Interface? Multiple sound inputs/outputs? :?:
