Thread
Strange board on Mac 512k
Hi,
Yesterday I picked up my first 512k. They are hard to get in Europe so I had to pay a whopping 20 euro for it ;-)
But, on boot no glory. I opened it up and after scanning the molded autographs (yes!) of the creators, I picked up a service source manual to see what was going on inside. But my 512 k did not only have a logic board on the bottom and another board on the right, but also one on the left. No serials, no inscriptions, just IC's and some connectors. The connector from the standing board on the right was disconnected from the logic board and connected to the alien board and from there reconnected to the logic board. From the alien board 2 other connectors could be found: something that looks like the mouse-connector from this Mac (also the modem/printer connector) and one connected with two small pins to a cable guided outside the Mac with on the end 2 audio-like plugs, like the ones you find on your old record player.
I can't post pictures here, but if you want a picture, please notify me.
Disconnecting this board resulted in a booting Mac, but now I need to make a boot floppy. How does that work since I only have 800k floppies? I checked the floppy-drive inside and it is definitely a 400k model. My SE/30 only seems to initialize floppies to 1,4MB (?), also really odd in system 6 is my guess...
Kind regards,
Jelle
Yesterday I picked up my first 512k. They are hard to get in Europe so I had to pay a whopping 20 euro for it ;-)
But, on boot no glory. I opened it up and after scanning the molded autographs (yes!) of the creators, I picked up a service source manual to see what was going on inside. But my 512 k did not only have a logic board on the bottom and another board on the right, but also one on the left. No serials, no inscriptions, just IC's and some connectors. The connector from the standing board on the right was disconnected from the logic board and connected to the alien board and from there reconnected to the logic board. From the alien board 2 other connectors could be found: something that looks like the mouse-connector from this Mac (also the modem/printer connector) and one connected with two small pins to a cable guided outside the Mac with on the end 2 audio-like plugs, like the ones you find on your old record player.
I can't post pictures here, but if you want a picture, please notify me.
Disconnecting this board resulted in a booting Mac, but now I need to make a boot floppy. How does that work since I only have 800k floppies? I checked the floppy-drive inside and it is definitely a 400k model. My SE/30 only seems to initialize floppies to 1,4MB (?), also really odd in system 6 is my guess...
Kind regards,
Jelle
Post pictures to imageshack and then embed them here.
For a start you may want to remove the extra board.
For a start you may want to remove the extra board.
Your SE/30 should be able to format an 800k disk as single-sided 400k format with System 6 or 7.
Hi all,
Thanks for your replies.
Here a URL with a picture, hope it works: http://img43.imageshack.us/img43/3598/img0659j.jpg
or
http://yfrog.com/17img0659jj
What program should I use on the SE30 to format an 800k floppy to 400k MFS? Or burn a system 2.0 image to an 800k floppy... This is such old technology, I lost all my knowledge over the years and the internet just seems to think I recall all the necessary steps...
Thanks all,
Jelle
Thanks for your replies.
Here a URL with a picture, hope it works: http://img43.imageshack.us/img43/3598/img0659j.jpg
or
http://yfrog.com/17img0659jj
What program should I use on the SE30 to format an 800k floppy to 400k MFS? Or burn a system 2.0 image to an 800k floppy... This is such old technology, I lost all my knowledge over the years and the internet just seems to think I recall all the necessary steps...
Thanks all,
Jelle
That's a most peculiar board. There are RAM chips it looks like, and it takes power from the MB power connector. Could it be a video card designed to drive a standard 9-pin CGA monitor or a TV monitor thru an RCA jack? I've never seen anything like it. 8-o
Give THIS LINK a whirl. Just about everything you need to know well written should help you.
Is this a 240V M0001WP European model? Or is it a 120V North American model?
H3NRY, if 240V European, could this be a PAL converter? I seem to recall the Apple II had quite a problem with that as well.
Is this a 240V M0001WP European model? Or is it a 120V North American model?
H3NRY, if 240V European, could this be a PAL converter? I seem to recall the Apple II had quite a problem with that as well.
It could, but it could just as well be an NTSC converter. Since Macs have their own display, there's no native NTSC or PAL video capability. I have seen a few people who did user group demos all the time who had a TV projector, back before computer projectors were common, and they had scan converters to drive their displays. Usually external boxes, though some means of tapping the video signal inside the Mac was needed. We designed one at Beck-Tech called the Chromatron which drove a standard NTSC monitor in color from a 128K/512K or a Plus, but it was an external box with its own power supply. It had a 9-pin output to drive a standard IBM / Amiga TTL RGB monitor and a composite NTSC RCA output.could this be a PAL converter?
Since Apple][s used TV sets for displays, they had to have different circuitry for PAL and NTSC. Early Macs are unique, not compatible with NTSC, PAL, MDA, CGA, PGA, VGA or any other format.
Ah thanks for that H3NRY, that's right the first Apple ][ only had an NTSC output, that's why PAL was such a headache.
I agree the board is most likely an internal scan converter if only because it has that 9-pin connector for a monitor as well as two RCA outputs. Do you think it also handles sound, hence the second RCA, or it has dual video outputs? The sound is carried through one of the pins on the power connector, so the board has access to both.
Love that the adapter you were involved with drove a color TV set. Could the Mac with this adapter take advantage of color in any way?
I agree the board is most likely an internal scan converter if only because it has that 9-pin connector for a monitor as well as two RCA outputs. Do you think it also handles sound, hence the second RCA, or it has dual video outputs? The sound is carried through one of the pins on the power connector, so the board has access to both.
Love that the adapter you were involved with drove a color TV set. Could the Mac with this adapter take advantage of color in any way?
A larger pic w/higher contrast so the chip designations are clearly legible would be a big help. Given that, and a good solder side pic, we'll be able to learn all there is to know about the hardware end of that card.
No markings on a two sided board (no ground plane) with that kind of trace layout, screams "prototype" to these old TTL Cookbook era ears/eyes!
:?:
No markings on a two sided board (no ground plane) with that kind of trace layout, screams "prototype" to these old TTL Cookbook era ears/eyes!
:?:
Yes, it could. I designed it so the pixels were clocked out at 14.31818 MHz with color burst like an Apple II, thus turning MacPaint fill patterns into colors. ChromaTron, see? :lol:Could the Mac with this adapter take advantage of color in any way?
I will make new, more and better pictures this weekend. Your speculations make me curious too. Even though I have always been wondering what the advantages of NTSC were/are, next to the existence of PAL (or even SECAM) it does sound eligible that the board has got something to do with a second monitor for this Mac. Checking the markings on the various chips on the board leaves me helpless on either a chinese website I can't read or stuck in a very technical environment: I am not a techie...
Hope you guys will check my next posting also. Thanks.
Jelle
Hope you guys will check my next posting also. Thanks.
Jelle
There are no advantages to NTSC over PAL. PAL is better in almost very way. Better refresh rate, better color resolution, better line resolution and no conversion problems between film and video which result in judder in NTSC systems.
Negative on the refresh rate, it is lower than NTSC.
Here a link with new and better photo's:
http://img638.imageshack.us/g/img8261r.jpg/
Thanks for looking and I look forward to your thoughts.
Jelle
http://img638.imageshack.us/g/img8261r.jpg/
Thanks for looking and I look forward to your thoughts.
Jelle
That is a weird board. That big plug which just loops back into the receptacle right next to it is just strange. However, with those two mini-jacks coming off of it I'd venture a guess that it is meant to hook into an Apple II or something like that, since they look like the pair of mono in & out one could hook into an Apple II for cassette support.
Not strange at all. When the board is in use, that is the standard 10-pin power and data plug that goes from the logic board to the analogue board. Like many adapters of this type, it instead goes from the analogue board to the alien board, then to the logic board. It routes, in particular, video and audio.That big plug which just loops back into the receptacle right next to it is just strange.
How exactly would such a board have worked between a Mac and an Apple II? I never heard of such a thing before.
My money is still on video output now that I see they are male RCA plugs. One video, one audio and one TTL.
Yes of course, 50Hz vs. 60Hz. However is that still a consideration with LCD? Film is 24 frames. PAL is 25 frames, and NTSC is 30 frames. In terms of video fluidity, 30 frames will be smoother. But in practical application 24 frames is pretty smooth and what we watch all films at on LCDs. I'll take the added resolution and reduced judder on a PAL CRT any day. On LCD though, I suppose it doesn't matter anymore especially since color is digital and that was the main advantage of PAL aside from resolution. In which case, more frames would be better for sports, so NTSC has a slight advantage now for that.Negative on the refresh rate, it is lower than NTSC.
NTSC also has the advantage with newer sets that are either 120 or 240hz being an exact multiple of 30 and 24.
I'll go along with that - mostly. It looks to me like the RCA cables terminate in a 2-pin plug at the mystery board, so my guess is they are wired together and bring the (mono) sound out to a stereo amplifier. The 9-pin plug is probably video for a TTL RGB monitor / projector, so neither NTSC or PAL. I'm still guessing - I haven't traced out the circuit or anything, but the chips on the board would be consistent with such a scan converter. It also looks very prototypish.My money is still on video output now that I see they are male RCA plugs. One video, one audio and one TTL.
The question is moot now in the USA because NTSC broadcasts have ended. ATSC digital is not NTSC.NTSC also has the advantage with newer sets that are either 120 or 240hz being an exact multiple of 30 and 24.
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
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.The question is moot now in the USA because NTSC broadcasts have ended. ATSC digital is not NTSC.NTSC also has the advantage with newer sets that are either 120 or 240hz being an exact multiple of 30 and 24.
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.It looks to me like the RCA cables terminate in a 2-pin plug at the mystery board, so my guess is they are wired together and bring the (mono) sound out to a stereo amplifier. The 9-pin plug is probably video for a TTL RGB monitor / projector, so neither NTSC or PAL.
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?
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.whether NTSC or PAL would use more or less circuitry, or about the same?
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!
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
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!
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