I didn’t think I could do much with the tab, and with the two cracked screw standoffs, I figured it was worth while to get it. I will have to say I am very happy with the fit and quality of the parts. I attached them with some JB Well 4400psi Epoxy.
I am doing another coat of paint on the lower portion of the case, partly in hopes of a sturdier finish, but also due to that crack that showed at one of the Din ports in the back. I had glued it, then I used some Epoxy on the inside to help it as well. I then used the White Putty in the crack to help blend it out.
With the top I cut the broken portion of the case tab off. It was the narrow one. I then installed Birt’s replacement tab. It was a perfect fit. Per his recommendation I did slightly round its edges and the two remaining tabs. I also put his parts on to reinforce the cracked screw standoffs in the top. I again used the White Putty on the outside of the crack in the right front corner of the case to help blend it out for the paint. While I had the epoxy, I decided to reinforce the inside of that crack with it as well.
The paint turned out really well. I put on about 3 coats on it. Krylon Fusion All in One Matte River Rock.
I ordered in some reproduction badges for the top of the case. Well I went with the “gold” model type labels. This thing is an odd machine, and the reproduction badges are great, but the way they are made is a bit different so it was not going to look exactly original from close up. So I am happy to make this rather neglected, and somewhat unique 64 look a bit more unique.
I have just finished replacing the electrolytic capacitors on the board. That will be posted in Part 3. The modulator was quite a pain this time around.
I still need to look at the * key and see if I can get it to be more responsive. The two “repaired” plungers are a bit off, the height is just a little wrong. I am going swap them out and keeping them as future spares. I need to open the keyboard to check out the * key anyways, I might as well switch them. I may redo them with epoxy sometime and try to adjust the height a bit more. I don’t know if that will be Part 4 and hopefully end up with it finished up.
I picked up another Commodore 64 breadbin model. It had a rough time in storage from the looks of it. The system has been in a damp dirty storage area, there were several of them being sold by the same person, in similar conditions along with some other old 80s era computers like Apple ii systems. I guess they were stored in a basement somewhere that had some real water/moisture problems.
As you can see from the outside it is a bit dirty, and some keys were missing. This was I think the second best looking of the batch. Below you can see the inside, the paper shield was a mess, black mildew along the bottom. A good bit of dirt inside. After seeing it in the bag, I decided I wasn’t even opening it inside. So I took it out back and opened it there. I removed the cardboard shield and it went strait to the trash can. The case was then hosed down to get the worst of the dirt off. I wiped the keyboard down a bit and the board before taking them in. The case parts went it the tub and got a really good scrubbing.
I removed the RF Shield and cleaned the board with some 91% IPA. It turns out to be a bit of an interesting board. Yes the screws are mostly rusty, the RF Shield and Cartridge port plate tells a tale of too much water too. On close inspection the board looks ok for the most part, the legs of some of the components are rusted, I clipped a them and the tips just fell off. This board has obviously been worked on in the past. The inner cardboard sheet that was above the bottom RF Shield went strait to the trash, it was about as awful as the upper cardboard shield.. I kind of like this brass looking shield, but without the cardboard to go with it, I won’t be reinstalling it. I don’t care enough to make a new cardboard piece.
You may notice the wires in the above picture. This is a 326298 Rev A board. An early board that only has the 5 Pin Video port. This board was built in 82 based on the unsocketed chips. The board had extensive work done to it. All of the main chips are socketed. They are all dated second half of 84. The 5 Pin Video port was replaced with the later 8 Pin Video port. There are two wires running off from that port, and various cut traces on the top and bottom to separate out the additional pins. I think in the VIC II area there were possibly some other changes. The VIC II area cage was (and still is) rather rusted as well as the RF modulator top plate, and the RF RCA Port was all rusted.
So after the ipa bath I hooked up the board.
It worked, no issues. Next I tested the keyboard, it worked, minus the two broken keys. Some keys were not very responsive though. I did a full teardown of the keyboard to clean it properly.
I first removed all of the keycaps with my keycap puller. I recommend one, they are rather cheap and good insurance to prevent breaking the old plastic. I next desoldered the wires on the ShiftLock key. I had removed the tape from around the keyboard, as you can see, to get to the screws under it. After removing the screws the board lifts off, and you can see the plungers then.
I took out the plungers and put them to the side, then took the keyboard frame and sent it to the tub and some warm very soapy water. I also soaked the keys in the soapy water. Then scrubbed the keyboard and keycaps with a toothbrush and rinsed them well and dried them. I also took the springs which were dirty and some were rather rusty. I put the springs into some White Vinegar. The Vinegar removes the rust, it does make the metal a bit dull looking. I expect if you leave them in too long you may break down the metal too, so I kept checking on them. They cleaned up well, the worst of them you could tell were actually pitted but were still in working order. I then washed the vinegar off with some water and dried the spring as best I could. I placed all of that on a towel to dry properly.
While that was drying, I took some IPA on a qtip and lightly wiped the contacts on the circut board. We don’t want to remove the conductive coating. If you clean too much of it off they keys won’t work. Next I took the plungers, and wiped the shaft part with a damp cloth to get any dirt off, I didn’t wipe the contacts on the plungers, they looked pretty good. They were mostly clean overall due to being covered by the keycaps and in the keyboard frame holes.
All of the good plungers and two broken ones.
Well, I had watched Perifractic’s Lego 64 videos, and I got an idea to try on the broken plungers. They did still work, as I had tested the keyboard with them, they just won’t hold a key now.
So I found a Lego laying around. You see the full piece I started with there in the lower left. I cut it in half, cleaned the plunger up and fited it to it. I shaved it down to go into the plunger shaft a little for more surface area and strength. Then I glued it in with a combination of Bondic and Super Glue gel. I DID have to file down the Lego piece, it was too large and the Commodore Key cap wouldn’t go on it. I used my small Diamond Grit Needle Files from Harbor Freight (they are just small files, I got the Diamond Grit ones, they seemed to work well for me on plastics). I will say that the glue doesn’t hold well, these tops will come off. So it isn’t a great fix, but I think it will work. I am still waiting on replacement Plungers and springs for the keyboard. I put the one plunger back at the British Pound symbol location, but I put the other at another key that is less likely to see much use. The 8 key gets a lot of use.
Here is the keyboard frame after reassembly.
Here is the keyboard back together back in the cleaned upper case. I tested it and it all works. The * key doesn’t work very well though.. When I get the new plungers in, I will probably remove the circuit board again and check that key. I don’t know if it it is the plunger, or dirt, or the contacts on the circuit board. Other than that and the missing caps, the keyboard was quite responsive, better than my other C64. That one I did not remove the board to clean the contacts. Removing to swap the plunger and check that key isn’t too bad. I will only have to desolder the ShiftLock key and remove the screws. The plungers that I am not working with will all stay as long as the keycaps are still on the keys can’t come out.
I does look much better than it did, but it is very streaked. The Power LED plate was actually corroded to the point much of the paint was lifted and flaking off. Corroded Aluminium.. Ya, I guess a good bit of moisture for a long period of time. I plan to get a replacement Badge and maybe a matching Power LED plate, I just don’t know what I want to go with.
Next I started on some preventative maintenance as well as rust removal. I had already removed the rusty tops of the VIC II area and the Modulator top cover. I then desoldered the Cartridge Plate and the VIC II cage which is rather rusty. I did alot of cleanup on the RF Modulator cover and Cartridge plate. A combination of wire brushes, sanding, and polishing with the Dremel etc. To remove the stickers easily, I put a little WD40 on them and let it sit. When I was done they were pretty decent. I tried some Vinegar on the RF Modulator cover, but that removes the protective coating that was still on some areas of it, so I stopped that. I did soak all of the rusty screws (basically every screw in this thing) in the Vinegar to get the rust off. I also removed the Fuse holder pieces, and fuse, they were quite corroded. I placed them into the Vinegar as well (well not the fuse). The Vinegar did clean the corrosion pretty well off the Fuse holder, but it left those areas black, I then polished them back to a shiny surface before reinstalling them. When all the rust was off of the screws and Cartridge plate and RF Modulator cover, I put some “Teflon Non-Stick Dry-Film Lubricant” on them. Not to Lubricate them so much, but to put a protective film on them to help prevent them rusting again. I did the same with the keyboard springs after they were dry. I don’t use the stuff on plastics though it puts a white film on that is hard to remove. So I put it on before putting them in place.
I resoldered the Cartridge Plate back to the board. I also touched up some solder points on the board. The VIC II cage will not be going back in either. I think the VIC will stay cooler without it, and with a proper heatsink installed.
Here is the board reinstalled after cleaning up the rusty bits.
The board was tested again and still worked. So next I installed a few heatsinks.
The 5 Volt Regulator doesn’t have much of a heatsink on it. The Rivet is loose and the heatsink is spinning around. So I decided to remove it and fix that as best I could. I took the heatsink off of it. I placed it on a new 2 Amp capable 5 Volt Regulator, it wasn’t needed, but that is what I keep around. I was a concerned that with the age and heat that Regulator dealt with over the years plus that loose tiny heatsink that it really should be replaced before it fails. When these regulators fail they most often fail open, meaning they will push the full voltage through them instead of dropping it or cutting off the voltage completely.. That fries the ics in the board. I have not heard of them failing inside the C64, while they are the big issue inside the C64 power supplies. With that very tiny heatsink, which was also not making good thermal connection to the regulator I didn’t want to take a chance on it. This time I put a second folded back heatsink behind it with thermal compound between the heatsinks as well as on the back of the regulator and bolted it all together.
This change to the Heatsink is an improvement, I guess. Still it seems very inadequate and gets very very hot.
As far as the case repairs go, I guess I didn’t take any pictures to show that specifically. The top of the case is cracked in the front right corner, it appeared to have taken a hit to that corner. It also has 2 cracks in some of the screw supports. I used my solder iron on a lower temp to melt the inside of the crack in the corner of the case together again. Then I put some liquid Testors Model glue in from the back to smooth it out. That did start to melt the plastic, I removed the excess glue. I have found that if you use that stuff and it melts the plastic and there is too much excess glue the plastic won’t harden again. The one standoff in the top of the care there is cracked as well, I haven’t fixed that yet, I think maybe from the same trauma that cracked the top. Three of the standoffs that hold the keyboard in place were sheared off as well. Those I glue back on with superglue gel. I then clamped them for a day and left it sit. That will give me the best strength, they shouldn’t be stressed while it is curing, which is 24 hours to get to full strength per the manufactures directions that is. The clamping ensures they are down properly and the joint is thin and tight too. After that I put some Bondic glue around them, the Bondic won’t cure in the crack because it needs UV Light to cure. I have also found it doesn’t bond very well compared to Super Glue. It does retain some flexibility and have some hold, I find that can assist Super Glue because it holds so tight, but doesn’t flex and fractures.
This case is badly discolored and I don’t want to try to retrobright it. I picked up some Krylon Fusion All-In-One Paint+Primer “Matte River Rock” paint awhile back to potentially paint a 1541 case. The case had some small chips out of the bottom. I took some Tamiya Putty “white” and filled in and built up the missing areas. It is a potent thin putty that dries quickly, and sands well for me. I it seems to bond to the case plastic well (As the model glue fuses the plastic, so I would expect the model putty to grip it well too). When I was done with the physical repairs to the bottom portion of the case, I put a even coat of the Matte River Rock paint on it. It turned out well. After the paint dried I found a crack show in the center of the half circle of the video port in the middle of the case. I glued that with the Testors Liquid model glue, I hope it holds well. Later I will put on some epoxy to help give that crack a little more support (I should have used Epoxy on the keyboard plungers instead) . I think once the board is reinstalled it will have more support where that crack is as well.
I haven’t done anything to the top of the case so far except weld and glue the one crack. The one case clip on it is broken off and lost. There are also 2 screws posts in the top that are cracked. I have thought about getting one of Birt’s “Hey Birt!” case saver kits to get a new case clip, I could use one of the reinforcement pieces on the cracked stand off, and have spares for the future. As I have to fix that case clip, I don’t want to paint the case yet, I will likely scratch up the paint having it upside down for those repairs. I will put several coats on the case. I want to test the paint on something with a Matt Finish clear over it. Some paints don’t mix well, and can cause the lower paint to lift or got to a crackle like finish. I have found that even with paints from the same company.. So I will test the Krylon Matt Finish first on a scrap of similar plastic (probably a modern computer case bezel). I want to put the clear over it, even though I like the existing Matt Finish of the paint as it should help protect it better.
So for now that is about it for this C64. In the future I will be doing more to it. The remaining repairs to the case. That include the Clip and post repair as well as painting and installing a new Badge plate. Checking out the * key, as well as installing the replacement keys and springs. I also have a capacitor replacement kit for it. With the 84 Breadbin I already worked on, I had found some capacitors that showed evidence of failing, so I figure this one is going to be served well by replacing them. I do wonder if that, especially the ones in the RF Modulator, may make a difference in the video output. I may or may not install some additional heatsinks. The computer is working fine, but it does have bad jailbars, so I may do something with that too at some point. I don’t know of removing the modulator and building up a replacement would help that or not.
I would love to know where the other Breadbins that were sold with this ended up and see that they were properly cared for. There was a very interesting VIC that I would have loved to see, but I wasn’t paying that kind of cash for a VIC let alone one that looked like it spent a few years sitting in water.
I picked up another Commodore 64 quite cheaply. This poor system had been stored in some bad conditions. I am not sure the conditions, but it had been wet at one point at least and damp quite a lot. When it was put there, it was probably pretty rough looking as far a browning of the plastic. This was an early Commodore 64 from 82 originally. Oddly the serial number label had no serial number printed on it. I have seen some labels that ink can be removed from by some cleaners, so I don’t know if it had been wiped off or never had a number.
Internally it as all there. The old paper foil shield was dirty and had mold on it. There was dirt and dead bugs all inside it. The first thing I did was pull the paper shield and toss it out, I then pulled the keyboard and mainboard out. Next I hosed the worst of the dirt and bugs out of the case with a hose.
Next I removed the bottom shield from the mainboard. It showed quite a bit of corrosion on it.
Before I tried to fire the board up, I did a bit of cleanup on the board itself. Then I looked it over to see if anything needed addressed before trying to power it on. I first checked that the power switch was making good contact. I then checked the Fuse was good. I also pushed all of the socketed chips in to make sure they were tight.
Looking over the board it was dated as 1982. There are some odd things about this board, it has had all the main chips socketed (all “wide” chips). The main chips are also all dated 1984. Three of the ram chips have been replaced and are also dated 1984. The remaining chips are all from 1982.
Here you see all t he main socketed chips. CIAs, the 3 Roms, the CPU, SID, PLA and VIC II from 1984
The next odd thing about this board is that it has a 8 Pin Video Socket instead of the 5 Pin Video Socket that was originally on it. julrod over at Lemon 64 said he had heard that Commodore service centers had upgraded the 326298 boards with 8 Pin Video Sockets. I have yet to test if the 8 Pin socket includes the added Chroma signal for S Video like video output (It does work and it works very well). Looking around the 8 Pin Video socket I saw 4 cut traces (some on the bottom some on the top) around it and there are two wires on the bottom side leading off to points on the board.
Here are the two wires off of the Video Socket, you can see some of the cut traces too.
I connected the cleaned up board to a display and my power supply. It actually came up to the normal startup screen showing all of the memory. The video was noticeably poor compared to my other later Commodore (a 1984 model). It has bad Jail Bars on the screen for one. I then connected up my full test harness an test cartridge. The board passed all of the tests. I fired it up with my Pi1541 and started up a game.
The next day I spent doing a lot more cleaning of the computer. The case was cleaned with some CLR Mold and Mildew cleaner, a brush and a toothbrush. It still looks bad due to the lack of the badge, the bad browning of the plastic. The plastic is streaked oddly in the browning as it isn’t very uniform. The top has a crack on the right front corner. Three of the mainboard mounts are sheared off. The narrow right tab is missing that holds the back on. Two keys are missing and the posts are broken on the keyboard. The keyboard worked, but it wasn’t very responsive. It is quite dirty as well of course.
Most of the screws are rusty. Some of them are very badly rusted, anything in the “front edge, including the case screws. I put them into some vinegar. After soaking in it for awhile, the rust was removed from them. It left them looking a bit different, but they were in much better shape. I also did the same with the keyboard springs.
I removed the cage around the VIC II area. It was quite rusted, and I don’t like them anyways, as it makes it hard to get to the parts inside. It may be a decent heatsink for the VIC II though, I replaced it with a real heatsink though. The computer has a factory mistake where R10 by the VIC is 300 Ohms where it should be 120 Ohms. Ray Carlsen recommended putting in a 220 Ohm resistor in parallel across the existing R10 to bring the resistance to what it was supposed to be. This corrects the resistor in at R10 brings the strength of the Composite Video output to what it should be.
Here you can see the new Blue 220 Ohm resistor stacked on the original R10 just to the right of the VIC II
Here is the keyboard disassembly.
I lightly cleaned the keyboard pcb with some IPA. Once it was put together again, it did seem like it was more responsive. I haven’t tested it fully though. Keep in mind that too much cleaning of the contacts will rub the carbon off and they won’t work properly.
For the keyboard I turned to a little inspiration from Perifractic at Youtube. I had to tear down the whole keyboard to clean it properly. It also wasn’t making good contact on some keys, so I decided I would clean the pcb on it. I don’t have spare keys, or posts. I decided I would try repairing the broken keyboard posts with some pieces of Lego Cross posts. It does look like it may work, I don’t know for how long though. The one key the “pound” key is one that I doubt I will end up using, so having a repaired post there shouldn’t be a big deal. The other key was the 8 key so I decided to move that post to another position where it will get less use. To do this was a combination of a drill bit, using a Dremmel, and Xacto knife. While the Lego Cross axel looks like the key post top, the problem here though is that it is just a bit too large. A Lego piece that accepts the Cross Axle will go on a Commodore Post, but a Commodore Key won’t got on the Lego Axle. I don’t know if some of the Lego Axles are a little different or what though the ones I had wouldn’t work with the keys properly. I ended up using a small file to file them down to a more fitting size. I found that superglue won’t get a great bond on Legos, Bondic doesn’t either. I did try some model glue, which was said to be able to fuse Lego pieces. I don’t know how well it is holding. I may eventually replace the damaged posts, but for now they are hopefully ok. I still need to get 2 springs and two keys.
I reassembled the keyboard with the repaired posts.
I also took the top off of the Modulator and cleaned and polished it up. The plate on the Cartridge Port had some bad rust on it as well. I desoldered it from the board so that i could get it properly cleaned up. They both turned out to be a good improvement. I was going to paint these pieces but decided not to. Instead I put some teflon liquid to try to protect them from rusting quickly. I also used it on the screws. It puts a bit of a coating on stuff and is used to protect tools from rusting as well. The other part/parts I pulled to clean up were the two parts of the Fuse Holder. They were badly corroded. I desoldered them and polished them.
The board now looks quite a bit better. I also installed heatsinks on the VIC II, SID, PLA, and CPU.
The conditions left the metal plate around the power LED corroding and the paint lifting off. I ended up cleaning it as best I could. I have to figure out what to do with it for painting etc. The main case badge was missing, and from the condition of the browning of the plastic , it must have been missing for a good while.
In an effort to get the old case looking a little better, I scrubbed the case with a paste of Baking Soda to get some of the marks off of the plastic. It did get rid of some of them. The plastic is still streaked brown.
For the crack in the right front corner on the top, I melted the plastic from the inside with my solder iron set to a lower temperature. This held the part in place, but for the crack on the outside, I used some model glue, that seems to have fused the plastic there pretty well. I also put a little on the inside to even out the melted plastic. Be careful about getting too much of that stuff on the plastic, it will dissolve it making it soft. It may not harden properly again if that happens.
Some of the pins in the components were rusted, and rusted badly on the bottom side. So I thought I would just clip them closer to the board. When I clipped at least two of these they just came right off. They were rust clear to the solder. I don’t think they were rusted below the solder. I tried to remove as much rust as I could. The presence of rust encourages the formation of more rust unless I am mistaken in what I have heard.
So far restoring this old beat up 64 has mostly been a lot of cleaning and some physical repairs. I did do the R10 fix. I still have more to do with it, and I am not sure when I will find the proper replacement keys. I was thinking of just ordering any key to put on the keyboard so I have a full keyboard, but I am not sure yet. I will probably recap the board. I have to fix those 3 board mounting standoffs that are broken off. I may fix the broken case tab on the right as well. The heatsink on the 5 Volt regulator is a bit loose, so it won’t be making the greatest thermal transfer to it. I will see about fixing that up before using the computer too much as well.
I am looking at the options for replacing the case badge. I also plan to paint this case and not to try and retrobright it or anything like that. The letters on the keyboard keys are also yellowed. On the left side it isn’t too bad, but as you go across the keyboard it gets quite bad. This computer will never be the best show piece. I think I like it though for the 8 Pin Video on the early board, and the main chips being socketed. I could easily use this board to test most of the typical breadbin primary chips. Being is such poor physical shape gives me a bit of freedom as this case will never be “like new” again, I can do what I want and not have to feel like I am harming it. It is a bit unique and it will remain so. I didn’t check the Chroma output on that 8 Pin video port yet, but I will get around to that probably later this week.
Once I was done cleaning it up, and I finally put the keyboard back together I fired it up again to try out a game again. I “think” it looks a little better onscreen. It still has noticeably worse jail bars than my other Commodore 64. I am only using it on my little 7″ composite display so I don’t know how bad for sure until I put it on a bigger display.
As I make progress on the restoration of this Commodore 64 I will probably do a followup post on it.
I picked up an old Commodore 64 last December. When it arrived it looked well maybe not great, but mostly clean.
You can see it still has part of a keyboard cover unit attached. That was quite difficult to remove actually without causing damage..
Internally it looked fairly clean as well. I took the computer out of the case and cleaned the case mostly with soap and water as well as an old toothbrush. I did use some Baking Soda and a bit of water to make a paste like cleaner to scrub some stubborn spots. The case ended up looking pretty good, it is browned a bit but overall not too horrible.
Here I have cleaned the case and keyboard.
Unfortunately the above images are what I was getting out of the computer when I first connected it up. It was flipping through a lot of garbage, I couldn’t even make it out. The camera picked up these images though showing me that something was working. Based on these images I expected a likely issue with the PLA to start. I ordered in a new modern PLAnkton chip to replace it.
Here is the board with the new PLAnkton PLA replacement, and a few caps replaced.Here she is working after putting in the new PLAnkton.
The computer was working again after replacing the failed original PLA with a new PLAnkton chip. I had to desolder the original chip and solder in a new IC Socket. Then the computer powered up normally except an issue with the Keyboard. It acted like there was a stuck key, after disconnecting the keyboard it still acted like a stuck key. I pulled the left CIA chip there in the upper left corner. It is the CIA that controls the keyboard input. With it out the key wasn’t showing pressed. It was replaced at some point in the life of the computer so it was in a socket. So that seemed to mean the CIA chip was bad. I ordered a replacement chip. As the CIA was super tight in that socket I decided to replace it before putting in the new chip. I actually happened to have a new old stock socket in my stash of the proper size. I installed it and figured, I would test the CIA and see if I could do anything with it. The CIA fit better into this new socket, and it worked perfectly as well. So now I had a fully working Commodore 64.
I did do additional changes, such as replacing all of the electrolytic capacitors. Removing the metal shield around the VIC chip, and installing heatsinks on many of the chips. I also put heatsinks on the Cassette transistor and 12 Volt regulator. I replaced the heatsink compound on the 5Volt regulator. I purchased a full capacitor replacement kit from console5.com.
I also purchased the heatinks, new Din plugs for the Power Supply port, Serial Port, and Monitor ports from Console5.com. I used a new plug for the power port make myself a new safe power supply for the C64 (See my other post on that). I used one of the 6Pin plugs to make a Serial test plug for the Diagnostic Harness (see my other post on the Diagnostic Harness) as well as another for a Pi1541. I picked up the Horseshoe Din for the Monitor/Display Port and made a new Composite Video cable with the audio going to two connectors so I would have copied “mono” audio on my TV. I will be making a S-video cable out of another connector at some point provided I come across a display with S-video on it.
It seems a bit across the board as to “replace the Electrolytic Capacitors” or others will say “Don’t”. I will say if you aren’t using good quality capacitors, don’t waste your time, the old ones may be better or last longer if the new ones are junk. If they are leaking everyone says replace the leaking ones. I say if some are leaking, then others likely could at any time. So far as my experience went on the Commodore 64, I did find that at least some of the old capacitors were giving unexpected values. The old 10uF capacitors varied from 10.8uF to as high as 15uF with 6-8.4% v loss and 3.1 to 25 Ohms ESR. The new 10uF varied from 10.5uF to 10.71uF all at basically 1.2% v loss and 2.9 to 3.2Ohms ESR. I feel at the least that 25 Ohm ESR one was likely to become a problem, I am not so sure about several others. I have to say as the Capacitor kits at Console5.com are $5 to $8 (depending on the board revision) for good brand name capacitors it was certainly worth it for me. They carry them for all of the Commodore 64 Revisions, as well as the Commodore 128, the Commodore 128 Power Supplies (well at least two variants) and the 1541 drives. They also have the Commodore 64 Saver kit.
The keyboard was quite clean overall. I believe the cover was on it most of the time it was out of the box considering it was nearly pristine and only a couple of the springs had any rust on them. I took all of the key caps off with a key cap puller. I then hand washed all of the keys with soap and water. I brushed off the keyboard base and cleaned it with some 91% Isopropyl Alcohol as well, but I didn’t have to take the keyboard apart beyond that.
Black Screen failure..
Shortly after replacing the last of the capacitors it decided to act up and black screen on me. I ran the dead test cartridge and it told me the one ram chip was bad. First I retested my new power supply that it hadn’t went into an over voltage state. It was perfectly fine. I ordered in a replacement ram chip. When I went to desolder the chip, I found the one leg had been clipped off (the VCC pin) at the top and the soldered back on, as well as one of the other ram chips. The only chips that ever seemed to have been changed out was the left CIA and the VIC. I guess it was having an issue and someone was trying to troubleshoot it, I am not sure if that was back when the PLA originally failed or some other point. Anyways I finished removing that ram chip, being careful not to have that leg fall off. I then installed a new socket and put in the replacement Ram chip. I still had the black screen. I pulled the left CIA just in case, as it was socketed and not required to get a display. I then tried pulling the VIC and used contact cleaner on it and on the socket for it. Finally I decided it was time to desolder the SID, I really didn’t want to do that because there was a risk in ruining the chip in the process. I didn’t have anything else to try at that time, short of desoldering more ram chips, which I didn’t have replacements for. I did have sockets for the SID chip as well. When I went to desolder the SID I found the leads weren’t clipped at the factory, and some were folded over. The one lead was touching an adjacent trace. I believe that was causing the fault. I had gotten that far and decided to desolder the SID anyways. I removed it and tested the system, and it came up normally (well normal for no SID or left CIA. I soldered in a new socket and retested, the system still operated fine. After that I went back to the SID and finished straitening the legs out and installed it into the new socket. I was so glad to find it still worked after that as well. I then reinstalled the CIA and swapped back in the original Ram chip, it also worked. After that I ran the diagnostic cartridge with the full test harness through quite a few cycles for good measure. I finished installing the Heatsink on the VIC as I had removed the metal case around it. The VIC is quite hard to get an IC Puller in at with that case nearly touching the bottom edge of it. I actually removed that case before pulling the VIC. Later C64s didn’t have that case over the VIC so I figure I don’t really need it there.
Completed repair, capacitors and heatsinks.Here she is working again!
Beyond that I cleaned the mainboard with an ESD Safe black brush to get the loose dirt off and some 91% Isopropyl Alcohol to get residues off of it as well as a bit of flux from the various new sockets as well as around the cartridge and power switch and the various ports.
It was fun getting this old machine going. I didn’t have one back in the day, although I had a used TI 99/4a at some point in the early 90s. So I guess that was my first computer, I didn’t really get to do much with it back then as I had nearly no software for it. I always liked the Apple IIs and such we used in school, and remember writing basic programs for them as well as later on doing that with our 486DX2 66mhz with Dos 6.2 and Windows 3.11 for Workgroups. I worked on the old 80s era IBMs including a few 5050s I had in the late 90s. I guess now I wish I had kept them. I even had a working luggable IBM 5155.. Well I never thought they would be worth anything more than scrap. Still I don’t know that I would have done anything with them. I worked on the IBM PS/2s in school, but never had one, even then I thought they were “weird”. The Commodore 64 is a fun system, and reasonably easy to work on.
It is a nice change working on these old computers compared to working on “modern” computers like I do during the day. It is nice getting into component level troubleshooting and repair.
After getting a second C64, I have found this unit has a only partially working SID. The third voice is not working on it. I only noticed it due to the other C64’s SID playing back more sound on the Diagnostics cartridge tests. If I used it more, I may have noticed some odd audio, but not being familiar with these computers back in the day, I don’t know how long that would have taken. I am figuring on getting a replacement, but I think I want to go with an ArmSID. Maybe next month I will be up to ordering one and see how it goes. My 128 has the same SID model in it, I could check it out to swap it, but I do currently have a fully working C64. I don’t have a good feeling for the chances of picking up a fully working original SID certainly a price that is much better than an ArmSID or other modern replacement. I like to keep them original as much as I can, but these chips are old, and not being made anymore, I don’t expect them to keep running another 3 decades.
Muldrf's Hobbytronic 