Coleco ADAM: A journey in to madness?

Charlie

.. . Mouse . ..
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Jan 20, 2008
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I freely admit to having a particular soft spot for 32bit Acorn computers. But one of my favourite things about being a confirmed retro computer nerd is discovering the foibles of old computers, especially systems new to me. With that in mind I've had a crazy hankering for a Coleco ADAM for a long time as it ticks all the boxes for me: I only have a vague knowledge of the system. There's much to like, both cool and these days charmingly silly. Also the system was such a glorious failure it saw off the company that made it.

So I thought it might be interesting to start a thread about my impressions and adventures with this machine.

I give you the Coleco ADAM:
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A Huge Pile of Awesome

I bought mine as a complete, boxed, system expecting it to be broken as the seller advertised it as "untested". It didn't disappoint as it was so big it was shipped in a wardrobe box, was complete, and didn't work.

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The Box is MUCH Bigger Than You Think

It's genuinely quite exciting to get this much computer, and back in the day I can see how this huge and heavy box containing lots more goodies than any rival system would appeal to punters. I bet that was Coleco's intention but store managers must have cursed them, especially with a returns rate of about 4/5.
You think Sinclair had a reputation for poor reliability and overenthusiastic release schedules? The Spectrum initially "only" had a failure rate of about 1/10, was cheep, and was made by a recognised computer manufacturer. Coleco made Cabbage Patch Kids, games consoles, and was going for Apple's market. In other words the system had a lot to live up to and had a disastrously bad start. Oh, and this was shortly before the infamous games console crash.
As I understand it Coleco had the sensible idea to follow up their excellent and very successful Colecovision games console with a compatible computer that would come in at a good price but still be a full set up. At the time every other manufacturer was selling pretty much only the computer itself for a headline price knowing punters would have to buy a bunch of other stuff when they got home and found their new toy couldn't do anything.

A well priced complete system is exactly what Amstrad later marketed to such effect:
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Amstrad CPC 464

So how did Coleco get it so wrong? Well, finding that out for myself is one of the reasons I wanted to get an ADAM. I also wanted to see for myself why the system is viewed with such affection.
 
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While the ADAM was a tad on the expensive side, it wasn't out of line for an all-in-one computer of the day...a fully equipped C64 would cost about the same, an Apple IIE was about 3-4x more expensive (even without a printer) and an Apple II clone would run you about the same (with 48K of ram...) (although, with those, you'd have yourself a 5.25" FDD instead of a tape drive)

It had a few pros, but many many cons...you also got a ColecoVision with your purchase, so this was great for anyone with a Coleco that wanted a computer (or had neither a computer nor a console system, but wanted both), and you got a full computer with 80K of RAM, it came stock with a tape drive, which in itself was both a pro (to a degree) and a con, as most systems came with (or at least had the option of...) a Floppy drive by 1983.

The fact it came with a printer was also both a pro and a con...you got, and paid for, a printer whether you wanted one or not (additionally, if the printer failed, you weren't just out a printer, you were typically out your entire system)...of course many people who had zero intention of using a printer, would certainly have rather just paid a few hundred dollars less for their system...

While it had a large CV library, it never got much software that took advantage of the (few) improvements of the ADAM, particularly as the system was orphaned just 15 months after release.

It did have a fairly decent Zilog Z80 CPU running @ 3.58mhz, as well as 80KB of RAM, which was a bit better than most other 8-bit offerings at the time.

however it was also one of the last '8-bit' systems released, and much better systems had started coming out in 1983 (IBM PC XT, March 83) and in early 1984 (Macintosh 128k - January 1984, a mere 3 months after the ADAM) granted both systems were a lot more money.

The ADAM had many issues, but I think the greatest being the fact that it was just 'too little, too late' in the marketplace for this particular system...to a certain degree the Commodore 128 would have a similar fate (albeit a better machine with a faithful Commodore following, it survived for 4 years...) as the Amiga was released very quickly after as well... (Jan 85 vs July 85 - the ADAM being discontinued in Jan 85)

also consider that it was competing against the C64, Atari 800, CoCo2 and many other systems (including 'budget' systems like the Vic20, Texas Instruments TI99/4A, Atari 400 etc), and the market was completely saturated.

However, I will say this, at 13 years old, I would've absolutely killed for an ADAM (or any other computer system for that matter) for Christmas '83.

(side note: don't fire up the ADAM with a tape already inside the drive, it has a tendency to erase tapes with it's strong EM burst on powerup)
 
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:)

I'm pleased to report my ADAM is now fully working and looking much better. Initially it was very yellowed, and when first unpacked, rattling alarmingly. It's a pretty easy system to dismantle and it turned out a couple of heat-sinks had been dislodged in transit so causing the rattle.

Initial impressions?
Quite a good looking system, separate keyboard, two Coleco controllers with a keyboard dock for one, and that infamous printer / PSU. Three things that stood out right away were how crappy the action of the keyboard is (cost cutting I'm sure) and the weird way some plastics were far more yellowed than others, particularly noticeable with the keyboard keys. Also the guts of the computer seem to have been thrown together, constructed very poorly, and there's a good few (seemingly factory) patches to the lower motherboard. All told the ADAM has the feel of an engineering sample, not a production machine.
Happily the motherboard came back to life after a darn good clean and re-seating of ICs in their sockets, a win in my book. So I got down to the task of disassembling and Retr0briting, starting with the keyboard:
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Stages of Retr0briting

The keyboard itself is very easy to take apart, removal of six screws on the back (one a different size!) allows the two halves to fall apart. The keys themselves easily pull off and the keyboard controller lives under a metal can. It's an amazing hotch-potch of different plastics (even the keys!), obvious design care, but seemingly poor electronic design with little care put in to construction. While the shell itself seems to be made from the same material as the system unit the keys themselves seem to have been made from four different kinds of plastic, seemingly at random - bizarre!
Most of it Retr0brited pretty easily, taking about three - four hours of sunshine, but the most stubborn keys (see middle-bottom photo) took four straight days! Even then I had to resort to a little bleach to get a near match to the rest. Just like the system itself, the keyboard has the feel of something that had much thought put in to it, but very rushed production engineering with corners cut to reduce costs.

The system comes with a couple of Colecovision controllers matching the colour of the system. I'm glad to say they work fine, but also needed a darn good clean and Retr0brite:

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Open and Connections

There's an amazing number of diodes in these controllers, I presume to help support the number pad. The connectors just press-fit to the base of the PCB, and as the colour coding was the same for both so I thought I'd post a photo. There's five screws on the back, and once they are out the unit just hinges open at the base. They are the same controllers supplied with the Colecovision and I'd call them an acquired taste. There's also a plastic keyboard dock thingy to mount one of the controllers into, not sure why? I understand the Coleco ports are Atari compatible (but for the keypad) so I think I may end up using something nicer once I have a few games to play.
 
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Great to see you got it going. Now.... what can you do with it? :unsure: :cool:
Is it stand-alone? I always thought the Adam had to be connected into a Colecovision?
The joystick press-fit wires are exactly the same as Atari 2600 joysticks and the Commodore rip-off of it.
The Colecovision/Adam joypad has the same pinout as Atari 2600 and other common DB9 joysticks of the era so it's pretty amazing that they figured out how to multiplex in an extra 12 keypad keys without additional wires.
Please post some more pics, especially the inside of the main unit and close-ups of the PCBs. I'm hungry for more :cool:
 
that is a properly wacky machine.

nice :)

So true... and I haven't made it to the good stuff yet! On to the system unit:

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"Fresh" From The Packaging

Once out of the box I could see it was a bit yellow. Also there was that nasty rattle, so I dissembled the thing before I did anything else. The first photo shows the groovy tape drive (more later) with an ADAM Net port front-right (more later). The dismembered corpse is in the second photo, yes two motherboards and shielding everywhere. Even so this machine gives such a strong EM thump when it starts that it will very likely erase any tape left in the tape drive or near the computer! I believe Coleco only found out about this after "broken" units started coming back, the manual states that the user should put the intended tape in the drive prior to powering up the system, oops. Coleco soon sorted that problem by adding a sticker to the top of the unit warning users not to do so!
The unit was dead easy to take apart, and even more than the keyboard has very much the engineering prototype vibe about it. Screws everywhere, two motherboards connected by ribbon cable, and a boat-load of wasted space. The lower system board also had a good few patches, seemingly of factory origin.

So the motherboard was cleaned, repaired, gotten in to working order, and the case Retr0brited:

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Post Retr0brite

That's better. A quick tour from top-left to bottom-right shows an Atari-type connector used for power and ADAM Net round the side, the tape drive, Colecovision cartridge port flanked by ADAM and Colecovision reset switches, and two Atari-type controller ports along with a Colecovision compatible expansion port round the side. With the lid off there's a three slot expansion bay and room for another tape drive. Round the back is a channel selector, RF out, Composite out, and multi-function DIN.


Let's take a closer look at those internals:

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Upper and Lower Motherboards

Once the first shield is off the upper motherboard looks pretty much like a Colecovision clone to me. The Video chip and it's VRAM, Sound chip, Z80, and ports all live on this board. The lower motherboard contains all the stuff that makes it a computer: System RAM, ROMs, I/O, expansion slots.The Video board looks nicely done to me, but the Memory board has a good few patches suggesting a rush job, and the pair have got me scratching my head a bit. I could understand the system having two boards if the memory board was just a straight expansion for a Colecovision motherboard and the pair shoved in one case to make a computer. But why go though a costly re-design and re-tool to make two new system boards and not integrate them together when that would be more reliable, cheaper to make, and result in a physically smaller system so saving further costs for all sorts of practicable reasons? I wonder what an expansion model 3 looks like inside? I realise hindsight is a wonderful thing but there are so many ways this system could have been done better, cheaper, and so more reliable.
I've seen an initial concept drawing for the ADAM which is basically just a black keyboard that plugs in to the front of a Coloceovision. The result looks a lot like a black Amiga 500 with two Coleco controllers nestled in the top. Quite groovy, smaller, and in the end I suspect that concept would have been both easier to make and more appealing to Coleco's potential user base.

I seem to be giving the ADAM a right bashing so far, and I haven't even gotten to the madness that is the Printer / PSU. But I also haven't gotten to the really cool stuff, and speaking for myself I can already see why the ADAM has that certain something that makes it's owners all warm and gooey.
 
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Great to see you got it going. Now.... what can you do with it? :unsure: :cool:
Is it stand-alone? I always thought the Adam had to be connected into a Colecovision?
The joystick press-fit wires are exactly the same as Atari 2600 joysticks and the Commodore rip-off of it.
The Colecovision/Adam joypad has the same pinout as Atari 2600 and other common DB9 joysticks of the era so it's pretty amazing that they figured out how to multiplex in an extra 12 keypad keys without additional wires.
Please post some more pics, especially the inside of the main unit and close-ups of the PCBs. I'm hungry for more :cool:

There were 2 versions of the ADAM, a full stand-alone computer and an add-on to a ColecoVision that turned it into an ADAM, also known as the Expansion Module #3
 
Here goes with next part of my ADAM retrospective. See what I did there? :picard

Here comes the Printer PSU unit:
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My What a Big One!

A large part of the Coleco's sales pitch for the ADAM, as I understand it, was you got a whole computer system with a 'letter quality' printer for the price of a... printer. Heck, the computer boots in to a word processor rather than BASIC as most other systems of the time did. At face value that's a pretty good deal, until you give it a bit of thought. I would say Coleco were going for the 'it's far better value than an Apple II' pitch. Which was certainly true, but I suspect anyone in the market for a upmarket system would not go for something with Coleco's name on it.

Oh, 'ADAM took a bite out of the Apple', get it?

Not everybody wants a printer, and even if you did you probably didn't want it set up all the time. The PSU and power switch for the system is built in the the printer, think about that for a mo'... yes, there was no way for Coleco to sell a system without printer. You would also have to have two printers on your desk if dot-matrix, or just a better printer was your thing. Did I mention this printer is probably the least well made part of the ADAM system, and also by far the largest and heaviest? Also it's REALLY LOUD, and at best can manage 10cps. Oh, and very prone to breaking which meant no computer even if you weren't bothered about the printer.

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The Belly of the Beast

I'm pleasantly surprised to report my ADAM's printer actually works, but I thought I'd take it apart anyway. More cleaning and Retr0briting. I have to say this thing is a true glory of cost-reduced engineering. Whoever designed this thing should have been given a Nobel Prize for creative engineering... and then banned from ever making anything again.Take a closer look at the pictures, go find some photos of the insides of some contemporary daisy wheel printers, and tell me this wasn't made by a mad genius.
Taking it to bits was really easy, a few screws in the base. But was a total SOB to put back together. Large pieces of flimsy plastic don't like to mate accurately enough to allow the very recessed self-tappers to go back in easily. On so many levels what were Coleco's designers smoking?

God, I'm in love with this machine!

Getting back to sanity for a mo' a better plan would have been to put the PSU in the computer, there's certainly enough room. Actually AMSTRAD went for a far better version of the 'all in one' sales pitch. Make a cheep, functional, computer that's reliable, easy to set up, and has a monitor as the main selling point of the package. Everybody needs a screen and all the PSU gubbins is already in there, not everybody needs a printer. Even though AMSTRAD were late to the 8bit market (1984?) the CPC line of computers, and PCW's, proved that if done right Coleco's plan wasn't madness after all.

That's it for my impressions. I don't think I've said anything that's not been said many thousand's of times before, but I hope some found this interesting. To me the ADAM is actually a lovely system that deserved to do very well but Coleco got their design philosophy, engineering, and marketing focus all wrong. It could have saved the company from the games crash in the USA but instead killed off it's creator. I'm far from done with this thread, I want to talk about some of the really cool things I've so far not touched on and start the modding process with a replacement PSU. Thoughts and ideas very welcome.
 
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While the ADAM was not a very good computer, in and of itself...

from a 13 year-olds perspective: you'd have crapped yourself Christmas morning 1983 to find that almost 4' x 2' x 1.5' (give or take) box under (in front of) the Christmas tree...a full blown computer PLUS a ColecoVision like many of your friends might have had at that point...

You might have even left other presents unopened that day... (which would actually be saying a lot, since Return of the Jedi stuff was also hot that Christmas, I remember our downstairs neighbors got an AT-AT, Jabba playset, Ewok Village and the Speeder bike which 'flew apart' at the press of a button)
 
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Of ADAM Net and High Speed Digital Data Drives:

A couple of really cool things about the ADAM are the way peripherals are connected, no really stay with me, and the storage media they use. Darn, I hear snoring.

ADAM Net:
In essence every peripheral for the ADAM has a fairly dumb CPU in it to run said peripheral and handle communication with the computer via a serial protocol called ADAM Net. I guess this is not the cheapest way to hook up peripherals but it seems one can daisy-chain as many devices as as you like to your ADAM. It tickles me that the ADAM Net cables and connectors look like household telephone line. Think of it as a kind of 80's USB where the computer only has to be concerned about communication and not running the device. Such a good, and seemingly well implemented, idea I wonder why Coleco bothered with these when there's an expansion port on the side:

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More Expense?

I wish I could find some useful info on the ADAM Net protocol and hardware specs, I can see some fun projects here. Oh, did I mention it's strongly recommended that all self-powered peripherals are left switched on, along with the Printer / PSU, and all plugged in to the same power strip with it's own switch? It seems if everything isn't fired up at the same time you're liable to blow a few IC's. Well done Coleco!

High Speed Digital Data Drives:
As far as I'm aware the mass storage system used as default by the ADAM is both ingenious and has an interesting history. When Coleco were initially speccing the design of the ADAM they wanted to go with a wafa-drive system rather like the abomination that was Sinclair's Microdrive:

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Oh the Humanity


Just like Sinclair Coleco seemingly had a sound reason for going with such a system. They wanted a low cost mass storage solution that was near to a floppy drive in performance when at the time of development floppy drives were too expensive for the price point they were aiming for. As I understand it the compact cassette tape, much beloved by UK home computer users, was not an option in the US. No doubt because the weather is generally better and so Americans didn't need an excuse to avoid going out in the rain for hours at a time. Coleco also had a cunning plan: As wafa-tapes were decently quick and much cheaper to make than solid state cartridges they were hoping they would make a viable replacement for games distribution. Coleco even got as far as the prototype stage but could never get the system reliable enough and, unlike Sinclair, decided to drop the idea for something that would actually work.


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Prototype ADAM

Hindsight is a wonderful thing but by the time Coleco came up with their own fiendishly cleaver idea for a mass storage system and shipped that with the ADAM floppy drives had come down to a sensible price and would have been a much better option. Indeed the ADAM did get it's own floppy drive in the end. Still, the High Speed Digital Data Drive was a really cleaver solution to a problem that was admittedly going to go away. Using largely off the shelf components was always going to work more reliably than the dreaded Microdrive on a tight development deadline caused by the failure of the wafa-drive.


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High Speed Digital Data Drive and High Speed Digital Data Packs
(not cassettes, honest)

Genius of this system was to take already mature technology and tweak it to make something close to the speed and capacity of a floppy drive. The only real difference between the, a-hem, High Speed Digital Data Drive / Pack and an audio cassette drive / tape was the head in the Coleco system read / wrote both sides of the tape at the same time. One track held the data and the other held indexing information which allowed the tapes, sorry Data Packs, to run reliably very fast for good loading times and something close to the floppy's random access. It's also quite cool seeing what looks like a cassette tape running so fast if it was a sprinter you'd swear somebody put a fire-cracker up their bum, and doing the whole forward-back thing you see with tape drives on old mainframes. Just one problem:

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The ADAM is very good at erasing it's own tapes

Oh, well. Charming in this day an age, probably not so much for owners of new systems. Especially as the manual told users to put the Digital Data Pack in the drive and then power up the system.Coleco 'fixed' the issue by sticking the above notice to the top of each computer once their many angry customers explained the problem.

A last thought. Here's a picture of the initial concept drawing for the ADAM. With all that's actually really good about the underlying architecture, and a ready made catalogue of games, I can't help but feel they would have done far better with their initial plans:
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Printer too small to house a PSU
 
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...And so the moding / upgrade process begins:

PSU components not here as yet, but for now the "factory PSU" will do. :roll:

What has arrived today is another Digital Data Drive:

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If Two Will Fit I Will Have Two

I'm led to believe two drives are a bit of an extravagance but I can now corrupt Data Packs twice as fast! Also I'm having some initial thoughts as to how I might be able to bodge an SD card in to one of these things... long term ambition.


Also my 8x4164 DRAMs have arrived:

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80k? Pah! Let's have 144k


I do love getting to know old systems while moding them. Progress pics shortly, I hope.
 
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Awesome thread so far, Charlie!

The eject button looks like a perfect slot for an SD card.
 
Awesome thread so far, Charlie!

The eject button looks like a perfect slot for an SD card.

:D

"New" Digital Data Drive Retr0brited and will be fitted shortly, but first some more goodies arrived:

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PSU, PSU Case, Serial Cable

I do believe it's time to make a somewhat smaller PSU for my ADAM. It will also be nice to have something with new components running the show and not to be relying on a rather cheep 'n dodgy step up converter.

Ingredients:
PSU Box
Serial Cable
Open Frame mains to DC PSU (preferably with 12v, 5v, -5v. The TDK ZPT40-512 I bought doesn't have -5v, the ZPT40-512N does)
Mains Lead and Plug (nabbed from extension cord)
Maxim MAX660 and a couple of caps to make a -5v output
3.3v LED and 68R resistor
Bits 'n bobs to connect it all together
Lots of hot glue!

For me the choice of components was dictated by first finding a suitable PSU case and then the PSU to go in it. Dual output PSUs are easy enough to find but triple output ones are not so easy. I picked the cheapest decent quality PSU I could find with 5v and 12v output that would fit knowing I had some spare MAX660s to make a -5v rail.
Some may remember I bought a bunch of MAX660s to make a groovy little power lead for the C64 that only needed a USB brick to supply the juice. To my knowledge the two I made are still working well but I made no more because of the generally negative response.

As cheapness was high on my agenda I wasn't bothered if the PSU didn't line up with the supplied mounting posts:

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I snapped out the supplied mounting posts, screwed them to the bottom of the PSU and then melted the ends with the side of my soldering iron to get the lengths even. Having a screw inside the post made this easy. The observant may have noticed a small board and components attached under the PSU. This is the circuit I knocked up to provide a -5v line:

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MAX660, Two Caps, Board, Wire, Solder, Done!

For any who are interested using a MAX660 to get a -5v line is very easy, there's a nice diagram showing the connections in the data sheet. As long as your capacitors are polarised, and the same value it's hard to go wrong. I soldered the Red and Black inputs to the underside of the PSU where two of the 5v and GND output pins are located, and in the case of this PSU soldered the White output wire to the underside of output pin 6. This was unconnected but would have been -5v out if I'd spent more money for a triple output PSU. The result:

20170907_131350.jpgBourjois Big Bollocked Boiler

The PSU was then placed in the bottom of the case and the stand-offs attached with the aid of lots of hot glue. Then I soldered the mains lead to the input pins, the ground for this PSU was part of one of the stand-off holes. I could have used proper connectors and fitted a power switch but... cheapness.

The next job was to wire up the output cable. As might have been guessed the ADAM needs 12v, 5v, -5v and uses a Male DB9 port, of all things, as it's connector. Looking at the ADAM the Male connector is wired as follows:

Pin 1) 12v
Pin 2) 12v
Pin 3) 5v
Pin 4)-5v
Pin 5) GND

Pins 6 to 9 are related to the ADAM Net connection for communication with the printer. For now I've not used these but may put an ADAM Net port on the PSU at a later date if needed. The lead I chose was just a Serial Null Modem cable with one end lopped off. Having buzzed out the wiring it was then a matter of soldering the relevant lines to the correct output pins of the PSU. I also added a LED (with resistor!) as a power indicator.

The result:
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Coleco ADAM PSU All Done

The output voltages all seem correct, in the right places, and there's been no escapes of Magic Smoke, so I guess I'd better go test it.

More anon.
 
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My I be the first to offer congrats on your work and thanks for the lovely pics and narrative:)

and ps the c64 power lead you made works PERFECTLY.
 
My I be the first to offer congrats on your work and thanks for the lovely pics and narrative:)

and ps the c64 power lead you made works PERFECTLY.

Most kind. :)

More to come, I've just made an AV port to SCART cable which has drastically improved video, and I now have sound! Piccies in a bit...

One roadblock: My PSU doesn't work, blast!
Full recheck, all the right voltages on the right lines. PSU specs meet the ADAM's needs, especially as it's not having to supply the printer. Odd... A bit of googling and it seems ADAMs are a bit of a SOB to get working with any PSU but the one in the printer.

Things I've picked up so far:
Some ADAMs don't like switch mode PSUs. That could be an issue!
Some ADAMs get really upset if the DB9 cable between the PSU and computer is too long / not thick enough. Ok, will shorten cable and a thicker one purchased.
It seems the ADAM may need a power switch on the PSU output lines. Doesn't handle a powering up PSU that well.

The ADAM also has two 12v lines. One goes to logic and the other goes to mechanical stuff likes drives / printer motor. As the PSU I'm using only has one 12v out I tied the lines together at the PSU end. The max combined current draw is less than the 12v out from the PSU but I wonder if the computer is so easily upset by spikes from it's drives and needs fully isolated 12v lines? I wonder if there's an ADAM PSU schematic anywhere?

As an aside the MAX660 is rated for much more than the ADAM draws on the -5v line, and the PSU has more than enough to supply both 5v rails.

There's also a "drain" wire on pin 8 which I haven't as yet connected... no idea what it's for, other than I assumed another ground, but might not be. I might try connecting that to Earth and see what happens.

Hmm, some fiddling to do...
 
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Nice work with the PSU!

I certainly could've used a MAX660 with my IIGS to get the -5V from the MeanWell PT65B. The 7905 regulator was just too noisy. I actually made the 220V mod into the original IIGS PSU and installed that back. Well the PT65B will get use as the A500 PSU.
 
Thank you!

It's been a day of ups and downs... I bought two department ADAM system boards for spares in case I couldn't get the machine running with what I had. They've arrived today, the memory board has a bunch of hand-written EPROMs in it so I'll fire up the ROM bower in a bit to see if they contain anything interesting. My "new" data drive works well and is much quieter so I might swap them round.

On the PSU front shortening the cable didn't help and making up a decoupling circuit to properly split the 12v line didn't help either. Bum!

I have a spare Meanwell PSU that is earmarked for an upgrade to my Master which I'll try but if itndoes work that will be good but another, larger, PSU case will be needed. For now PSU on hold until the thicker DB9 cable I ordered arrives.

On a happier note my AV go SCART cable is working well. DIN sockets have always been my soldering kryptonite for some reason. I'll post a how-to in a bit.

Over to Mockingchick thread:

*Edit*
Same result with Meanwell PSU...
 
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Nice work with the PSU!

I certainly could've used a MAX660 with my IIGS to get the -5V from the MeanWell PT65B. The 7905 regulator was just too noisy. I actually made the 220V mod into the original IIGS PSU and installed that back. Well the PT65B will get use as the A500 PSU.

I Installed the same PT65B in my GS a month ago using a 7905 and it all works Perfectly. Iain's too :)
 
Well that's just bl**dy odd!

Plug in DIY PSU; whatever I try the computer just doesn't want to know. Looking at other's DIY PSUs it doesn't look like I'm doing anything different...
Ok let's try wiring an ATX PSU soldered direct to the inside of the ADAM power connector. Still no joy, even when I've properly split the 12v lines. When the ATX PSU is off and the ADAM is powered from it'sown PSU it won't start, but is all fine again if ATX wires removed.

The computer just won't start seemingly if anything is hanging off the power lines other than the OEM PSU even if said device is powered off. Some further thought required I think, if anyone has a bright idea or a legible schematic of the ADAM printer/PSU I'd appreciate it.
 
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Nice work with the PSU!

I certainly could've used a MAX660 with my IIGS to get the -5V from the MeanWell PT65B. The 7905 regulator was just too noisy. I actually made the 220V mod into the original IIGS PSU and installed that back. Well the PT65B will get use as the A500 PSU.

I Installed the same PT65B in my GS a month ago using a 7905 and it all works Perfectly. Iain's too :)

Good thing it's working for you guys. Mine was making a distinct hiss, and I can't think of anything else than the 7905 and the circuit related to it being the cause.
 
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