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[C128 Tower]

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Welcome to my C128 "Tower" project page - Version 3
[Tower version 3]

This page is intended to more or less document the building of my third C128 tower. The image shown here is what it looked like when complete. Scroll down for the details on how this one was made. Click any image on this page for the associated full-sized photo (where available).

They say the third time's the charm, and indeed it almost was for my tower project. I had fully intended to do everything *right* this time - no cutting of the case, no double-sticky tape to mount stuff, only a little drilling, and minimal modifications to the various hardware devices to be installed. For the most part, I did okay with this iteration, but I still had to break those rules a number of times.

After you've read this page, you may wish to head back to the Current Version page.

Friday, December 11, 2009

I had to pull my CMD HD out to look at something for a friend, and while I had it out, I began to realize that the way I had it mounted inside the tower was rather slipshod. In addition, the drive mechanism itself is about to be replaced, so now seemed like a good time to tinker with the CMD HD a bit.

[Empty case, with studs]
[Front of the new casing]
I realized that the tower already had something that was perfect fit for these 5 1/4" drive bays - the CD-ROM drive. So I dug through my junk box and found another one that was of no use, and tore it apart, salvaging the case. The innards of the donor drive ended up on Abe's desk, for a thorough post mortem. :-) I then epoxied some studs to the inside of the case to mount the CMD HD's control board onto. I had some trouble getting things to line up nicely and also be able to press the epoxy down onto the metal properly, and the epoxy hardened before I could get one of the studs back in straight, so I had to superglue the sucker in. It looks and works just fine this way. Next, I took the faceplate I made previously and epoxied it to the front of the casing, and then shaved down one edge to make it fit nicely into the front of the tower (previously, it was rather tight). The studs originally attached to it for the LED board are still useful, so I didn't mess with them. One of the screws interferes a little with one of the control board studs, but not enough to be a problem.
[CMD HD boards inside their new casing] Mounting the two boards was a no-brainer at this point - just screw them down firmly. I used small-headed screws on the main controller board to make sure I was completely clear of the traces and pads near them. What is not shown here is that I had to insert those red fiber washers between the LED board and each of its studs, to get the distance just right for the buttons (without them, the buttons are pushed in all the way). There's enough room underneath the main control board to possibly fit something in like a laptop hard drive, or perhaps a memory card reader. At present, neither of these is likely to happen - I'm sticking with a normal hard disk for now. Don't mind the black tape on the DOS EPROM. The original label fell off some time ago. That connector with the two soldered pins is where the original power switch used to connect. I soldered it that way quite some time back, to turn the controller board on permanently. At some point, I'll undo this and replace the solder with a pair of shorting jumpers.
[Completed CMD HD] At this point, I just had to plug the SCSI cable in and fasten the top panel back onto the bottom with its original screws. When I put the drive into place, it just slid in nicely, like any other standard 5 1/4" device would. In reality, the casing is upside down relative to the original CD-ROM drive, but that's OK - the tower's drive bays are pretty much the same as most others, with two sets of mounting holes.

Friday, April 3, 2009

The floppy drives and CD drive looked too plain without their standard nameplates, labels, etc., so I decided to rectify that issue. Nothing major, but worth an update since it changes the appearance of the tower. I also replaced the control panel label with a higher-quality version.

[The labels on the tower] For the FD2000, I just cut and trimmed down an OEM FD2000 label to fit on the knockout plate under the floppy drive mechanism, similar to what I did with the CMD HD label. For the 1571, I combined hand-drawn graphics, images downloaded from Wikipedia, and a scan of my custom faceplate to generate the standard tan nameplate and a transparent-looking C= logo to simulate the molded-in logo on the original faceplate, both finished and attached in the same manner as the main control panel label. With regard to the CD drive, which needs black graphics with a transparent "background", I decided to try an experiment. I applied a piece of tape to a piece of paper, then another on top of that. I then printed the "CD graphics" image mentioned below onto the tape, in the highest, most-ink-using mode my inkjet(!) printer offered, let the image dry overnight, and then applied a third layer of tape to laminate it. Then I peeled the top two layers off in one go and stuck them onto the CD drive. A little careful trimming and it looks better than I expected. Getting the frosted look for the LED's on the replacement control panel label was simple - I first made rectangular holes in the label for the LEDs to shine through, then applied the layer of tape to laminate the label. Finally, I just rubbed a finger back and forth across the back of the label to smudge the exposed parts of the tape's adhesive.

Tuesday, March 31, 2009

[Ctrl Board Connected]

[LED/Power/Amplifier Control Board]

The next step after dealing with the paint was to construct something to put behind all those switches and LEDs. Here is the completed LED/Stereo/Speaker control board, with amplifier board plugged in, all hooked up and ready to use. That is a piece of ordinary cardboard between the amplifier and the control board, but it is just a prototype after all. Hopefully this will all be condensed into a single board in the future. It looks like a rat's nest of wires inside the 128 now, but so is the case with any computer that bears lots of LEDs, switches, ports, etc.

Here's the prototype of the control board with its amplifier module. That's a standard 20-pin ATX connector on the corner, of course. The IC to the right is a garden-variety 7474 (Dual D-type Flip-flop), powered by the ATX "+5v Standby" line and triggered by the power-on switch. Only one of the two circuits in this chip is actually used at the moment. The IC at the bottom is a standard-issue 4066 (Quad analog switch). Two of the circuits handle the stereo/mono select and the PC speaker output, a third handles the 1571 enable line, and the fourth is unused. The transistors serve as LED drivers. Four are NPN for high-active signals, the fifth is PNP for the 1571-is-#8 low-active signal.

I realized shortly after I posted on March 25th that I'd made some critical mistakes on the board. The PC Speaker output lacked any kind of amplifier or matching circuitry, putting too much load on the SID chips and 4066, and the AC coupling components near the audio-in connector were indequate as well. I fixed the AC coupling issue, but after several failed attempts to make a really small, basic pre-amp circuit, I decided that the control board just doesn't have enough space for a proper multi-stage amplifier, so I had to add an "auxilliary" connector containing ground, +5v, and the switched audio line coming off of the 4066. I then built what I needed on the smaller amplifier board seen to the side of the control board. These images show the revised circuit. The amplifier is built with 2N2222 and 2N3906 (and equivalent) transistors, two 1N4148 diodes, and a handful of resistors and capacitors. The Speaker-Out connector has been moved from the control board onto this sub-board as well. The way the two boards fit together makes it possible for me to just remove the amplifier module and speaker in one go if needed, or to replace it with a better circuit, without disturbing any other part of the circuitry, and in theory, without removing the control board from the case. That little chink on one corner is there to leave room for the mounting screw under it.

[Control board Schematic] This is the schematic for the control board. The control board prototype was put together sort of on the fly, without first drawing a complete schematic, so this image is technically reverse engineered from the prototype. A few things of particular note: The power-on circuit was my own design at first, but it didn't work right. A bit of searching on the web turned up this schematic, detailing the exact circuit I needed. That schematic can be found in context on this page, which deals with ATX power supplies on the Amiga. You might also notice that the circuit that handles the 1571-enable line has a redundant transistor/resistor circuit driving the LED. This is an oversight, a bit of cruft left over from changing things around and realizing how best to implement this function in the first place. It'll be optimized away eventually. Update December 22, 2009: A couple new capacitors and a 74LS74 was all I needed to fix the Power-On circuit. The schematic at left reflects this change, but the photos above do not.

[Amplifier Schematic] Here's the schematic for the amplifier module. The design is based closely on this more generalized version, which I found on this electronics website, with changes here and there to accommodate my supply of parts. After building it as close to spec as I could, I then tweaked a few resistors until the circuit could handle the SID's rather unique output.

Tuesday, March 10, 2009

Some folks thought the picture of the tower (bottom of yesterday's entry) was a little lacking, and I agree. Here are two new ones.

[Front, re-painted]
[Back, painted]
Aside from the first "painted" photo being kinda weak, I decided that, even though I kinda liked the result, the blues were still too pale (in reality, that is), so I picked up a can of Krylon "True Blue" and let loose with it on the tower. The images still got washed out and neon-ized thanks to my camera's flash and limited lighting, but it looks way better than before, overall. These photos still don't quite do it justice. I never quite planned out the coloring that should go on the right hand side of the tower, so I just kinda winged it - a little magenta here, a bit more yellow there, etc.

Monday, March 9, 2009

Below are several images taken during the different stages of painting the tower. There were a few minor hiccups, and the paints didn't blend the way I wanted, but the result looks nice, and is close to what I wanted anyway.

[Scratched up] The case started out pretty scratched up, dented, and generally not in the greatest of shape cosmetically. A lot of that came from having already had it for years and not really caring what happened to the paint - I was gonna re-paint it anyway!
[First round of sanding] The first thing I did was use some (OK, a LOT of) elbow grease and sand it down real good. By the time I was done with it, half of the paint was stripped off. The black "X" marks indicate dents that need to be fixed.
[Masked (side/back)] Next, I masked off everything that wasn't to be painted, and also to keep paint out of the inside of the case. In retrospect, I should have done this later in the process, if only to reduce the chances of tearing or damaging the masking bits and making double work. Fortunately, that didn't happen.
[Masked (front)] The front panel was tricky, thanks to the irregular shape of the control panel itself, the need to safely stuff the 3.5" floppy drive, and the rolled up bits to plug the CD burner's audio plug and 1571's lever spindle. I thought the blue light covers over the 'hard drive' and 'power' LED's were going to be a problem, but they came right out, no biggie.
[Filled in the dents] Next, I filled the dents. The only filler compound I had, if you want to call it that, was good old-fashioned J.B. Weld. It's intended as a repair compund, but it works fine for this purpose too.
[Sanded again and washed] Well, I thought it would work. Turns out that, while it fills the dents nicely, it's a royal bitch to sand down properly. I actually had to pull out my file for a couple of spots, just to knock the high places down before sanding. After I finished, I wiped the entire case down with a wet cloth, just to get rid of the dust.
[CD burner close-up]
[CD burner graphics]
Before going further, I realized the CD burner was going to pose a problem. So, I took a few really close shots (as close as my camera would allow), picked the best one, and then used it as a guide to draw a new set of icons and graphics to be deposited onto the drive later. I'll probably use inkjet wed-slide transfers for this.
[White base coat] Finally, it's ready for painting. First thing I figured I needed to do was go ape with the white paint, and so I did. When I was done with it, I seriously thought about stopping there - plain white paint actually looked kinda good in this case. I Went with the cheap stuff for this step, and learned quickly why it was so cheap. After a few tweaks to fix some bad paint, I bought a can of Krylon white and went to town, applying several thin layers. I left the machine to dry overnight.
[Immediately after painting] I thought that, if a printer could produce nice photos using cyan, magenta, yellow, and black inks, so could I with paints, so I went out and found three *very* close matches - Krylon "Sun Yellow", "Blue Ocean Breeze", and "Watermelon". I laid the colors down in that order, and then eventually started using two cans at a time to get the colors to mix better. In the end, I think I should have chosen a darker shade of blue. Oh well, I can always add it later, and the result already looks good - this photo, for some reason, washes out the blues and greens.

Sunday, Feb. 22, 2009
[Revised Front Panel] After much delaying and general lack of interest (that's how these things go sometimes), I've started working on the tower off and on again. Here, you can see that I've finally built a nice looking control panel for all the gear inside. Ironically, as nice as I think it looks, it's still only temporary! I was thinking of drilling some large holes and countersinking those buttons. They only have about 1/8" of travel, so they'll only stick out a tiny amount. In the meantime, here's the result. In the meantime, I've also a prototype LED control board, but it isn't finished yet. None of the LEDs that require this board are hooked up yet.
[Main View of Tower] Here is what the tower looks like in its nearly completed state. I'd call this fully completed, but there are still a few things to do inside and outside. The case has become scratched up, stained, and even hit with acid once, causing lots of blemishes in the original paint, so I've edited most of that stuff out of these latest pictures - good thing I plan to repaint it!
[Paint Job Idea] This image is a photoshopped simulation of what I hope to make the case's paint job look like. I used The GIMP to create this image and decompose it to a Cyan/Magenta/Yellow component image. I can use this "color key" as a painting guide; now all I need is white primer and the aforementioned primary colors, and I should be able to basically paint it the way an Inkjet printer does with paper.
[Case Mod Idea] I had thought also about cutting the side of the case and making a large window and adding a Commodore logo. The result would look something like the image on the left. This image was created before I actually put the case into use, hence the empty appearance and slightly different simulated paint job.

Saturday, Feb. 4, 2006
[HD cabling] Abe and I frequently watch the local FreeCycle Yahoo! group, and lo and behold we found a bunch of older SCSI equipment that someone was giving away. Within that lot, I found a much nicer CD-R drive (4x read, 2x write) and some nice cables. Luckily, the CD-R also provides termination for the SCSI bus, so once everything was hooked up, I was greeted with a directory listing I hadn't seen in months - my CMD HD's root directory! That little white wire snaking away from the HD and into a power connector is just that - a temporary power connection until I put in a proper DIN plug.

Tuesday, Jan. 17, 2006

As per usual, waiting to buy parts is what's taking so long :-)

[128+1571 boards] The disk controller on my 128-D board decided to die, so I opted to replace the -D with a flat 128 and a regular 1571 drive instead. I had to get creative with this one, and mounted the 1571 board over the 128 board via long threaded stand-offs, one of which (not pictured) passes through one of the large holes commodore put in the middle of the board :-).
[Expansion cable] While Al had the 128, he started to restore it back to a more sane state. When I got everything back, I decided to continue that trend with the flat 128. In the process, I had to make a new cable for the expansion port. This one is made from an 80-conductor flat ribbon, the kind commonly used for IDE cables. The lines are arranged as signal/ground/signal/ground... so that no two signal lines are adjacent, similar to IDE and SCSI cabling. The ground wiring is hidden under the tape.
[RamLink voltage regulator mount] The RamLink is mounted to the bottom of the case, similar to my first tower. This time, the RAM board is mounted securely too, using two little 1/4" threaded stand-off's at each corner. This also serves to make the bottom of the case into a heat sink for the RamLink's main regulator.
[RamLink power supply] I ended up almost forgetting about the RamLink's power supply. I brought a live 110 VAC feed down from the power supply, which I connected to the plug on the power supply. I then mounted it to the back of the case with a couple of tight zip-ties, over two fan vents. I've since moved it down to an area I don't plan on using for anything else, leaving the two fan vents free. The grey cable snaking out the back is the User Port extension cable.
[9VAC transformer and relay] Like any C64 or C128, this one needs 9VAC. The thin blue and green wires carry 12 VDC to the coil pins on the relay on the right, while the black wires carry 110 VAC directly from the mains input inside the power supply. When the 12 VDC line fires up, the relay switches on, passing the 110 VAC through the primary side of the 10:1 transformer. The 11 VAC coming off the secondary side is carried by the thick blue and greenish-white wires to the C128 board. The black wires branching off and going out of frame carry un-switched 110 VAC to the RAMLink power supply.
[Inside of the tower] Here's what the inside of the tower looks like now that it's almost complete, with the new boards in place.

Monday, Dec. 12, 2005

While waiting for more parts to come in the mail, I continued to work on the tower a little here and there as money permitted.

Mainboard Drill pattern The hole pattern on the C128-DCR mainboard did not match up with any of the tower case's existing mounts, so I had to create my own. When I switched over to the flat 128 board and 1571 drive, this pattern had to be totally changed; none of the holes I made for the 128-DCR board line up with a flat 128.
RL Drill pattern In order to mount the RamLink properly, I had to drill a few holes in the bottom of the case also, similar to what I did with the first tower.
Insulating the edges I decided the simplest method of insulating the two edges where the mainboard risks shorting out, was to just tape a couple of small pieces of cardboard into place. This happens to be part of the cardboard insulator used in the bottom of a flat C128.
Power supply hacked! Here, I tapped one of the DC lines inside the power supply, and ran the wires to a relay and transformer circuit bolted to the outside of the case (see above). Originally, I picked up 5 VDC, as pictured here, but I ended up having to switch to a 12 VDC line instead. That was my own fault - I broke the 5 VDC relay I planned to use. This picture doesn't reflect that change.
Power supply hacked again! Here, the live 110VAC mains input has been forwarded over a pair of wires, which will carry it to the RamLink power supply.
New motherboard header I decided that it was time to make this machine look nice, so I took all of the wires that had been added to the maiboard, such as the reset switches, audio out, and so on, and routed them all to a single, centeral header connector. When I switched to theflat 128, I had to separate this header into two pieces - one for the 128 mainboard, and the other went onto the 1571 board. What pins the 1571 already had (such as the LED connector), I dropped from the connector I put on it, of course.
A variety of connectors The new header provides a convenient place to use standard PC-style 2- and 3-pin connectors (like the kind that go to the front panel), to tap into the available signals. The tower will use quite a number of these connectors, instead of all those soldered connections and taped-up wires everywhere, as in the previous implementations.
Use heat shrink tubing this time! Al Anger pointed out a problem with one of the extension cables the last tower used - the electrical tape I used had dried out and started to peel off. So instead, I used heat shrink tubing everywhere that it could be used in place of tape. The result looks a lot better.
1571 extension cables It was necessary to extend the 1571's wires and cables so that they could reach the motherboard. The last tower needed this modification as well, but this time, I did it *right*. Also, I've since covered the 1571 cabling with some mesh loom to make them look nicer. Update: Feb. 22, 2009 - I had a problem with my 1571 drive (failure in one of the heads, which I couldn't repair), and had to replace the mechanism. In so doing, I also swapped the positions of it and the CMD HD controller board. This allowed me to skip extending some of the cables; only the head cable needed it this time.
Extension cables all over It was also necessary, as with the last two towers, to create new extension cables for all of the C128's ports. Unlike last time, every one of these extended ports will be attached to a proper rear knockout panel, if possible, as shown here. What doesn't fit on a knockout panel, will be put in the space in the middle of the back panel that is normally reserved for the special connector insert provided with all ATX mainboards. Update: Feb. 22, 2009 - I removed the audio and 40 column video ports shown in the picture, and replaced them with four RCA connectors on a knockout panel. Two carry Y/C video, the other two carry the left and right audio channels.
FD-2000 re-modified In keeping with the new policy of using nice connectors everywhere, the two twisted-pair wires were removed from the FD-2000 controller and replaced with a couple of 2-pin headers. The floppy drive (not shown) was modified to replace the wire tail it had with a proper two-pin connector. The FD-2000 has taken some minor damage over the years, I have to admit. :-(
RamLink re-modified Pictured here is the LED board from my RamLink. This one actually came from Al, as did the RamLink now being used. The one Al sent was intended as a spare for parts, and mine was already in bad shape from years of use/abuse, so when I finally killed it (blown regulator I think), I took parts from it to repair the one Al gave me.
SuperCPU re-modified I had to glue two of the headers on the Super CPU to it's board and wire them point-to-point to the pads originally used for the Unit-Enable and Turbo-Enable switches. The third connector, on the right, is for the Turbo LED and mounted straight into the holes originally meant for the LED.

Friday and Saturday, November 18-19, 2005

Got my parts on Friday, so I've been hard at work cleaning everything up and preparing everything for the new tower case.

3/4 View
Left side
The new case is actually something I had on hand, sort of. Abe (my then fiance, now my husband) was kind enough to give me the case he used on his box, replacing it with another, less fancy case that we had on hand. It seems to be in good shape except for some scratches that were there when we first got it.
One of the side panels
Back of the case
The case is a full-size ATX tower, similar to my first one, but in much better shape, and with modern, removeable side panels instead of that clunky old one-piece cover common with older PC's. Vents can be found on the top, the side panels, the back, and the front. The case came with a standard, 300 watt ATX power supply, capable of 5VDC/30A and 12VDC/10A.
The motherboard I'm using the same C128-DCR motherboard I have been using for the last several years. I took the time to clean up the wiring a little, and labelled the wires in the picture so that you can see what they're really for. You'll note that the MMU board appears to overlay the SID chips. In fact, it does, by way of a pair of wire-wrap sockets to raise the motherboard's MMU socket up high enough to clear the SIDs.

Test fitting the motherboard

Before starting on repairs/cleanups of the other components in the system, I needed to test-fit the motherboard (so that I could also estimate the lengths of some of the wiring). It fits reasonably well.

A very close fit!

There is a minor issue with the motherboard where it comes into contact with the 5 1/4" drive bays. I had this problem with the first tower as well, but in this case, it's less severe. The red lines indicate the problem zones.

Repaired the SCPU connector

The SuperCPU expansion port connector had becomed damged over the years, with all the constant tinkering, soldering wires to it, etc. I decided to do my best to repair the edge connector, and it now fits into it's female counterpart correctly.

SuperCPU and RamLink module(s)

I decided, however, to leave the SuperCPU and RamLink attached together as in the second tower setup. There's plenty of room at the bottom for them to stay this way.

Closeup of the SCPU/RL connectors

When I originally put them together, I did so by hacking bits of the SuperCPU's connector until there was room to get my iron in there, and I soldered the two connectors together permanently.

CMD HD SCSI host adapter

The tower contains a CMD HD of course. When I originally sold the second tower to Al, the shipping company dropped the package and among other things, broke the RamLink backup battery, causing damage to the back side of the host adapter. I've cleaned it up and used some parts Al sent to make a nice new cable for the LED board.

FD2000 floppy controller

As before, I will move the Activity (left) and Error (right) LED's to the front panel of the tower.

The floppy drive itself, modified

Because a standard floppy drive turns on it's light whenever the motor spins up, even if there's no actual data transfer, it is necessary to route the FD2000 controller's "Activity" signal to that LED so that it shows the actual status.