Apple IIGS RGB Monitor & SCART Cable

In a prior post I mentioned I have the Apple II RGB Monitor cleaned up and I needed to make a cable for it. Since I was making a cable, I decided to make a RGB to SCART Cable. This will go with the GBS Control devices and let me use modern displays. I had an old piece of cable used for a VGA cable originally that I thought would be a good use. I had a SCART Connector that in my spare parts that I had ordered awhile ago. I just needed the 15 Pin DE15 Male connectors.

I based the SCART Cable on https://roger.geek.nz/apple2/scart.html

Based on the source post at VintageWare, I need to wire the Red (2), Green (5), Blue (9), Sync (3), Audio (11) and three Ground pins (1, 6, 13) from the DE15 to the proper Pins of the SCART connector. It also requires using the 12V pin (8) wired two two other pins on the SCART connector via some resistors. The 12V should be wired by a 1k Resistor to Pin8 on SCART to select AV Mode. The 12V should be wired to by a 270 Ohm Resistor to Pin 16 on the SCART Connector to set the SCART input to RGB Mode. I am not using this cable on a true SCART TV, so those two pins should not have any impact for me, but I might as well make it to the proper specification.

This SCART cable was nothing but trouble due to the wire I have used. Everything just kept going wrong with it. The cable has Coax lines in it for the video etc, which is great, but very problematic to work with, this may not be as common an issue, but I am expect working with multi pair coax will commonly have at least some of these difficulties. The core wires for the signals kept breaking off at the solder point. The cable is overly thick making it not flex easily, and break them more. The DE15 connector Pins push inward out of the plastic housings (which I have never seen before, but may be common on cheap connectors..). The IIGS has thick plastic around the ports, and the Shells for the DE15s don’t fit, they don’t let the connector go in far enough to make a connection. That is common on Commodore 64 Joystick ports as well (although that is a metal surround). It was very frustrating. When testing, I just removed the Shell from the DE15, it went it great, except some pins started to push out, then when I removed it more of the coax signal wires broke off. When testing it before trying to take it out, I didn’t have the blue signal. I figured another broken coax signal wire. On inspecting I couldn’t find an issue, well visually inspecting, although the sync wire had broken off by then it couldn’t have been broken before unplugging it..

Next I repaired the DE15 end, cut down the Shell “lip” that holds it on as much as I could. I pulled all the extra DE15 pins out. I used Liquid Electrical Tape to insulate, and basically “glue” the pins into the connector and keep the coax signal wires from flexing and breaking. I also used the Liquid Electrical Tape on the SCART Connector. Then I let that fully cure. I reassembled the connectors and tested again. I again didn’t have Blue, only Green and Red. I further shaved down the Shell lip, thinking maybe it just wasn’t making contact. That made no difference, still no blue. I tried the old SCART to HDMI adapter box, and I got no video output from it. I decided I would make the cable for the RGB Monitor by cutting the cable in half and installing DE15 connectors on both making it into two cables. This cable was awful the worst I ever made. I took a week or so away from it as I didn’t want to mess with that cable again.

The cable would have been a little neater, but I didn’t initially intend to use the 12V line so I had to solder on that blue wire to the stub of one of the remaining wires. The various wires kept breaking off at the solder points and I kept adding in little bits to extend and try to get tension off of them. I am not happy with this cable. Hopefully as I went on further below I will get this working and it will be a solid cable after all the trouble and fixes listed lower in this post.

Above you can see the Liquid Electrical Tape applied to the connector. I put it all over the pins to the base. I has a good bond to the pins and case, this has locked the pins in so they don’t push out. It also holds the thin coax cores giving them support preventing them from breaking off easily.

Moving on to the RGB Monitor Cable

I decided to start fresh with the RGB Monitor Cable, I wasn’t interested in working with the other SCART cable again. I had a piece of shielded cable that isn’t individual coax for the signal wires that I decided to use for this cable. It is much smaller and flexible. I again pulled all unneeded pins from the connectors (partly as they like to fall out of these, but also as I needed them for another connector for the IIGS). This cable took nearly no time at all to make. It was easy to work with, had the exact wires in it that I needed. I even soldered the shield to both DE15 housings without any issue. I did take the modified DE15 Case Shell from the SCART cable. This cable took nearly no time at all to make, it was refreshing and was a joy to put together compared to the SCART cable.

For this basic strait through cable, I used pins 1, 2, 3, 5, 6, 9, and 13 as well as soldering the Shell to the Shield wire. This is a lot easier than the SCART, as I don’t need the Audio, the 12V, any resistors, the Grounds are just “strait through”. With the SCART most of the grounds were tied together, which is just more work in itself. I usually only wire the Shield wire to one end Shell or the other to prevent ground loops. In this case, the specification was to wire the Shell to ground, so I figured I would do it.

This cable I did not put on the Liquid Electrical Tape, as I had with the Scart Cable. Nothing here is binding, pulling etc, there isn’t excess loose bare wire, the Shield Ground is soldered directly above one of the Ground Pins and can’t reach the R, G, B or Sync pins easily unless it breaks off. I did not have issues with the pins pushing out yet, I think it helps that so many pins are “removed”, creating less friction, less chance of minor miss alignments etc. Granted I did go back and remove the unused pins in the Scart cable as well. The pins were repurposed for the wDrive DE19 to IDC20 adapter in another post.

I connected up the monitor and it worked great the first time. Well I didn’t have the right colors initially as the cable fell partly out of the back of the IIGS. I pushed it back in and everything worked properly. I then used the screws to screw it in. I didn’t have to modify the shell on the monitor end, it has enough clearance for the shell.

I do think this monitor has been used a fair bit, it is clear and bright enough though. It looks better in person than in pictures. I noticed a crack the lower left front corner of the case just above the Apple Logo.

Back to the SCART Cable

On getting the RGB Monitor cable working, I looked at the SCART Cable again. Not that I wanted to after all the problems with it, but I had it apart after taking the DE15 Shell off. I checked for loose or broken wires, although everything is covered in Liquid Electrical tape making that difficult. I didn’t see anything. I then started checking continuity. I was checking all of the ground wires, checking that I didn’t solder wires to the wrong pins. On checking the ground wires, I found the Blue signal wire was shorted to ground. I had checked that pins went where they should and that the Blue pins were connected, what I had failed to check the first time was if it was shorted to another pin such as Ground.. That will cause the Blue to not work. I inspected the DE15 end and it didn’t look like anything was wrong there. I carefully removed the liquid electrical tape from the Blue signal and the Ground pin beside it on the SCART end. I found the blue somehow jammed itself into the ground. Initially I thought the blue signal wire in the coax had broken, but somehow the blue was pulling into the shield ground around it. I hate that cable. I got it worked loose, and covered it in liquid electrical tape again. Then I let that cure, checked for shorts again and reassembled it. This SCART cable is wired differently than the ones I have made in the past. I have added the resistors and used the 12V power to Pins 8 and 16. That won’t matter to the GBS Control, as those pins don’t do anything on it, but I do wonder if it will make the SCART to HDMI act differently, or if it will make the SCART work on the Sony LCD TV which I have never been able to get to take any input. I figured I had the wire for it, (and I did do pin 16 in the other cables, but not pin 8) and it was easy enough to wire up. I then tested it on the GBS Control and the SCART Cable is now working properly. I then tried it on the SCART to HDMI Adapter box, and it worked on that as well. There was some “noise” in the display, but I think I had seen that is actually there on the IIGS and masked on the CRT Monitor.

I plan to likely use the IIGS with the SCART cable to the GBS Control more than anything. The Apple RGB Monitor has certainly seen better days, and if I use the IIGS very heavily I will probably not use the monitor with it. I actually didn’t intend to get the IIGS, and I don’t currently have room to setup yet another computer. I could put the G3 iMac away somewhere, as all I have for it is Oregon Trail..

Apple IIGS Maintenance

I ended up with 2 Apple IIGS computers. They were nearly complete. They were dirty, a lot of evidence of mice or more.

I did a basic wipe down of everything to get some of the nasty stuff of of everything before loading them up to bring them home.

On inspection at home, overall I had 2 Apple IIGS computers, with keyboards and the cables but the one keyboard has keys that are stuck and some damage. I also have 3 5.25″ disk drives, a Color Monitor (minus the cable), and a Monochrome Monitor.

I will be making various posts going over the equipment.

The primary thing was to check out the IIGS computers. I needed to see if either was working or reasonable to repair.

I focused on the first IIGS. First I cleaned it a bit better as it was still not very clean. I had checked both IIGS internally for leaking batteries, and thankfully neither battery had leaked, they were dated 1992. On seeing that they were in battery holders I was able to look up that these are the later ROM3 version boards with ROM3 and the additional ram. I removed both batteries, and gave the boards a visual inspection, they looked fine, a bit of dirt and dust.

From there I went to the power supplies. I opened the first one, it is apparently an ASTEC model. The visual inspection of the top looked pretty good overall, although the RIFA cap has some cracking. Nothing scorched or bulging etc otherwise initially.

On removing the PCB from the case to get to the RIFA cap, I found a surprise on the bottom. Under the Large Filter cap (C4), was a leaky black mess. Over toward the nearby C5 there was a mess and the solder mask and solder points looked bad nearby.

I first cleaned up the muck with some IPA while I was preheating my desoldering gun.

I pulled C4 and C5. The large C4 had no marks under it, it didn’t appear to have leaked. C5 though showed evidence of leaking. I take it leaked and migrated across the board, possibly through that large hole or somehow it managed to leak through the board some other way. There is a small pin hole under C4, but there was nothing on the top side, though the hole was plugged up with the gunk. The solder was quite contaminated around a good number of those solder points, and was a bit difficult to remove that old solder from those corroded points. I then had to use the fiberglass brush to remove some of the solder mask where it was damaged and the traces were corroding.

I used my MESR-100 ESR Meter to check C4 and C5. I also checked their capacitance. The large C4 330UF 200V capacitor had the proper Capacitance reading and a good ESR Reading as well. I reinstalled it. With C5, I was surprised to find the capacitance on it was still in spec for a 220UF capacitor, but the ESR was way to high. I’m fairly certain it was where the leakage came from as well, unless it was something that somehow ended up falling into the power supply. I replaced 220UF capacitor with a new one I had in stock. The board isn’t beautiful, but it cleaned up fairly well, everything was superficial. I removed the RIFA, and as I don’t have any spares in stock, I am just going to use it without one to do the testing and get one on order. I removed one of the resistors that had corrosion on the legs, and cleaned it up a bit before soldering it back in.

Above, it how the pcb looked after cleaning up the old solder and resoldering everything. The 3 now vacant holes in the upper left are the holes for the RIFA cap.

I tested the power supply output, and the +5V, -5V, +12V, and -12V all looked good. The +5V was right on, the others had a little variation being a bit low.

The other power supply is a Dyna Corp model. It has 4 RIFAs in it. It also has heat discoloration on the PCB.

I decided I wasn’t going to remove the 4 RIFAs, and that with the state of the PCB (and that I don’t “need” 2 working IIGS computers at this time), that I was going to just close this Power Supply up and not use it.

Now that I had one power supply working, I decided to test both mainboards with it. Since I didn’t know the condition of either monitor and I don’t have the RGB Cable, I used my bench LCD monitor with Composite video. Both mainboards powered up and showed the expected display.

I moved on to one of the Disk Drives. I just picked one of the three drives to do a cleanup and service it. I cleaned the case and cable with Windex and paper towels. I then took it apart. It was a bit awkward to get the drive out of the shell with how the front faceplate locks into the top and bottom halves. I then had to remove the top metal plate, and then the PCB and insulator and other plate below it. From there it was dusty inside, but looked fine otherwise.

I cleaned it internally with qtips and IPA. I cleaned as much of the dust from inside, as well as the rails. I also cleaned the print head with a fresh qtip and 99% IPA. I then put in new Silicone Grease on the rails and worked them a bit to make sure it was distributed well.

Just before putting everything back together, I saw something in the bottom of the drive.

Thankfully I found that and removed it before powering it on. Old gum wrappers some fool stuffed into the drive slot. With one of the drives, I wasn’t able to fully insert a disk into it before loading them up to bring them home, by the time I got home with them, I was able to insert the disk fully. I expect that was this drive, and that had moved out of the way.

I was still testing the IIGS, so I decided to test the Disk Drive before putting it back in the case.

The drive worked properly. I wasn’t making any unexpected sounds, and read the first disk just fine. I had 3 disks, and I tried the other two, and one of them worked. The last disk did not work properly, it would partially read but get to a point that it said to insert the proper disk.

That little Eyoyo monitor does a great job with Composite. It is very forgiving, and I expect when using any of my other monitors on Composite video won’t look as good.

Unfortunately Oregon Trail is not one of the disks, so that means I will have to get solution to let me play it on one of these machines. There are some other programs I would like to try out as well. I have more cleanup to do, the IIGS cases are a mess as well as everything else yet. One of the IIGS cases must be brittle, the lower frame as the one catch that holds the top was already broken when I got it, and then the second one broke when I opened it.

I finished cleaning the Disk Drive’s case and reinstalled it. I also cleaned up the intact keyboard just enough to use it, and it seemed to be working fine. I didn’t test all of the keys.

I found out these will not pass their self diagnostic without a good battery. I need a battery, and replacement for the RIFA cap. I also have to properly clean all the other parts including the IIGS cases.

NABU PC Black Screen, FAN Repair and Checks

Like a lot of other people I purchased one of the NABU Personal Computers that came up for sale in November. My Nabu arrived in December. It all looked good, when I turned it on there were two problems, the fan was making an awful noise and while I was getting a video signal it was a blank black screen. I opened the cover to look if something was out of place, and to check that fan. I pressed all the socketed ICs, reseated cables, tried other displays. Nothing helped and I didn’t feel it was worth shipping back. I mean even if scrapped I expect the computer was worth keeping.

I did inform the seller and he offered to send me another if I shipped it back. I decided to keep it in hopes of getting a second one, but there were none for sale. I kept looking back and recently he had some listed without the keyboard. I figured I probably had a working keyboard so I purchased a second one.

The new one came in and it worked with my monitor just fine. I was initially happy that the fan wasn’t making any noise, then I realized it wasn’t turning at all. I could hear that high pitch sound that likely indicated a stuck motor, which after opening it I found that was what was going on. We will get back to that later.

Now that I had a working Nabu I decided I would look at the other unit. The fan was noisy and I had pulled it back in December to check it. I connected it up to the monitor to see if it was in the same condition. It was still just displaying a black screen (it was powering on, and there was video signal), I didn’t realize it but looking at the LEDs on the front may have indicated if it was doing anything. Interestingly the fan was working much better, again I will get back to that later.

I found a guide to help trouble shoot the Nabu here: https://github.com/RudyRetroIntel/Vintage-Computer-Diagnostics

I have worked on a number of 80s era computers so there were a few things I was going to try. I started by pulling the power supply to get the fan detached to check it further. While I had the supply out, I checked it and reflowed some solder points on it. I didn’t see any issues with the power supply soldering, except I felt some pins were a little light on solder. I also polished all the connector pins on the power supply. They were pretty clean, but it was easy to do while it was out. I put the supply back in without the fan attached just for testing.

I pulled the mother board to get full access to it, and check the bodge wires on the bottom against the guide. It is the same revision of the board as in the guide, and has the same wires on the bottom (except different colors).

While I had it out I really don’t like that the LED board doesn’t have a connector on it. I put on a regular pin header and made a cable up and soldered that to the LED board and reinstalled it. Checking over the main board I didn’t find any issues. Before I reinstalled the mainboard though I rechecked the bodge wires, two of them had been pressed into and poked on component legs, I moved them and rechecked as I reinstalled the board.

Above you can see the LED Board with the original ribbon cable. I rewired it with a removable connector to make servicing the NABU easier in the future.

I pulled all the socketed ICs starting with the video generator ic. That IC had very tarnished legs. I take it that is due to the type of coating on that chip, I see that type of tarnish on IC and connectors and such. I used a fiberglass brush on the legs being sure to also do the inside of the legs. The IC Sockets on the Nabu look nice, but I still put a bit of contact cleaner into the socket before putting the IC back. I did the same with all of the other socketed chips. The video generator was the only IC that looked questionable.

On the left you see the video generator chip before cleaning, then the right is the chip after cleaning it.

After cleaning the ICs and reinstalling the board the Nabu was working properly. The fan still needs to be reinstalled but it all seemed to be working otherwise. They were tested before shipping out, so I expect it was a bad connection on some chip, possibly that one above.

The next thing to do was fix the fans on both of the computers. I was thinking about why the fan seemed to be working well on the first Nabu as it wasn’t before I took it apart in December. I figured it just freed up. Then looking it, it was still rubbing slightly. I pulled the fan from the Second Nabu, it wasn’t turning at all. I found the blades rubbed the outer frame just at the bottom. Looking at it closer I could tell there was no gap in the bottom and a wider gap at the top. The fan comes apart by taking out three small screws, this separates the motor from the frame.

The fans are very heavy. They are made of cast aluminum apparently, both the frame and the blades. They have been sitting so long, it seems the fan motor settled a little bit and slid down where the blades are now catching on the frame part. To correct this, you just have to take the three small screws loose on the back and get it properly centered again and reinstall them. There is very little clearance on these old German made fans. Modern fans are all plastic and many have far larger gaps between the blades and the frames. After doing this process with both fans they are properly centered again and moving freely without noise or any catching on the frames.

I reinstalled the fan and added a connector so that I can easily put it out off I have to in the future.

These computers do not appear mass produced. There is hand done work with the various cables and connectors. There are odd choices in assembly. The fans only have 3 screws holding them in, there are washers on the screws, flat washers glued to both sides of the fans, those locking washers glued to the top of that flat washer on the inside and a nut glued to that (which the glue has failed from removing them). The LED board on the front has spacers between it and the front frame. The fan has one connector that is removable, but the other one had a permanent splice crimp on it so it couldn’t be fully disconnected. The oddity that is the power cable from the power supply to the mainboard, which has no connector on that end either. The LED board being permanently soldered to the mainboard. That LED board is difficult to remove having to bend one or more of the LEDs to the side to get it out, possibly due to the LED leads being left so long do to having to use those spacers. It feels like they were designed and had some issues that were addressed, it would have been cool to see a “Rev 2” Nabu without the little oddities. I like the system, it is just a bit odd.

I look forward to using the Nabu. I guess at some point I may look at coming up with a keyboard for the second unit. I really like the Nabu Keyboard. I keep realizing I probably should have more pictures of these things working.

PSU Bottom, Reinforced Ground connector on the lower right corner.

Both of the NABU Power Supply Ground Lugs pushed off the pcb when reinstalling the ground wire to them. The pcb is a single sided board and has no through hole plating to keep it solid. The first one pushed and tore the copper the first time I went to put it back on, and I thought maybe it wasn’t solid or fully seated when it was put on originally. I pulled the power supply out and repaired it, by soldering some heavy wire around the pads and adjacent pin to reinforce it. Then tonight when getting the fan reinstalled into the second NABU the same thing happened to it. I know that one was soldered on well, as I had reworked the solder points on it and had even added solder to them. I pulled it back out again and did the same reinforcement with some heavy coper wire around the solder points. The picture above the ground connector is on the other side of the board there on the lower right corner. The two points from the lug holes and the one hole to the left of it are now all joined up with the wire in the solder. I was careful reinstalling the ground wire so as to not tear it free again from the copper. With that fixed and the fan reinstalled both of my NABUs are working now. I do only have one Keyboard, I’m wondering what it would take to build up a replacement keyboard. I would love to have had keyboards for both, but the current listing for them doesn’t include keyboards. I don’t see myself using both at once, I hate to keep a fully working unit as a spare parts machine though..

The second NABU worked perfectly out of the box, it had some rust along bottom of the back edge of the case top. I cleaned that up scraping away the worst of the rust, then used a fiberglass pen to get most of the rest. I then put some clear nail polish to protect the metal a bit. Beyond that I fixed the fan as described above, as it didn’t spin at all. The fan is now removable as I replaced the permanent crimp connection on the one lead with a connector. The system looked good otherwise and is working fine. I didn’t do any other modifications or changes to it. That unit is back in it’s box sitting on the storage shelves.

The other unit which was the one giving a black screen before pulling and cleaning all the socketed chips, I also fixed the fan on. It is the unit I put the removable connector on the front LED Panel. This was the first NABU I purchased, and it is the one with the matching keyboard so it will be the one I keep out to use. It also now has the fan removable with the detachable connector on the second wire on it.