Commodore VIC 20 - Restoration; Part 2, Video Modification, Electrolysis Rust Removal and Electroplating!

For this entry, I am revisiting my VIC 20; I was very happy with the work I did but the Video Out Signal to my LCD TV was pretty rubbish as can be seen from the following photo.

 

I decided to have a look and see if there was something I could do about it and stumbled across the following Youtube clip

https://www.youtube.com/watch?v=4tbvpRiM36E

Here, Noel talks about faulty VIC chips and the fact that he stumbled across his modification by accident! Glad he did as the results are pretty spectacular. Many thanks Noel!

 

Here is a list of the components and tooling required for this modification.

 

220pF Ceramic Disc Capacitor

100nF Ceramic Disc Capacitor

470pF Ceramic Disc Capacitor

Thin piece of equipment wire (I used yellow 10/0.1mm equipment wire)

A small piece of heat shrink sleeving (I used 1.5mm sleeving)

Heatgun (for sleeving; you can use a soldering iron to do this part but will need to be careful)

Soldering Iron

De Soldering Pump (solder sucker)

Pliers

Cutters

Wire Strippers

Tweesers (optional)

Flux (again optional)

Isopropyl Alcohol (again optional)

The 220pF Capacitor has the following markings

221

 

The 100nF Capacitor has the following markings

104

 

The 470pF Capacitor has the following markings

471

 

Now let’s have a look at the schematic.

 

Here is a close up of the circuitry we are interested in.

The mod on Youtube advises that we remove FB7 and replace it with a 100nF Ceramic Disc Capacitor.

It then advises that we replace C13 to its original position (I will add photos later)

And finally it advises that we solder a 470pF Capacitor from pin 2 of the VIC Chip to the video output connector.

Highlighted below  is FB7 and C13 on the schematic

Here is a picture of the modified schematic.

Highlighted is the area on the mainboard that we are interested in.

And here is a close up

Look at the state of that RF Shield! Age it appears has not been kind to it! As I have invested a wee bit of time into restoring this beautiful computer, I decided that I should do something about the RF Shield. All will be revealed once I have completed the video modification!

 

Firstly, and I advise you do this; remove the RF Shield completely as this will give you easier access to the components you are going to have to change and move around.

 

This is a wee bit trickier than it looks and may give problems to those without adjustable soldering irons. I tried my electric de-soldering pump to try and de-solder the joints on the circuit board which hold the RF Shield in place. Unfortunately, my electric de-soldering pump couldn’t supply enough heat to melt the solder on the vias. So it was back to my trusty twenty year old RS Solder Sucker and soldering iron.

 

I turned the temperature up on my soldering iron, heated the solder joints and removed as much of the old solder as I could. Unfortunately, this did not remove enough solder in order to simply lift the RF Shield off the circuit board.

 

Now, I had a couple of options here; one safe and the other not so safe.

The first option I considered was to heat the pins up individually then prise the rf Shield up on each corner… not safe! This could damage the Vias on the circuit board.

 

So I opted for the safer option which was to resolder each joint with fresh solder, then try the whole de-soldering process again. This worked slightly better but it did take a couple of goes on a few of the solder joints.

 

The RF Shield was still a bit tight  but I found that if you get a small flat headed screwdriver and gently prise the shield up on each corner (ensure that all solder is removed beforehand) it will lift up and you should have a circuit looking like this.

 

The two components we need to remove (C13 and FB7) are highlighted below

 

As I did earlier to remove the shield; I re-soldered each joint then de-soldered. I will add pictures of this process below

 

Apologies for the clarity of the next couple of pictures showing the removed components (they were taken from a video clip)

 

The above photo shows the removed Ferrite Bead FB7

The next component to remove is C13 (it is a 220pF Capacitor which looks like a resistor and has been placed diagonally and soldered) It looks like this is a standard factory modification made by Commodore as there is actually a space for C13 on the circuit board with one of the via’s going to a different part of the circuit.

Refitting that 0.4inch pitch into a 0.1 inch pitch would be extremely difficult so I opted to use a new regular 220pF Ceramic disc capacitor.

Below is a photo of the PCB with C13 removed.

Now it was time to solder the new components into the circuit. Before I did so, I added flux on the Vias and solder points for the additional 470pF capacitor. I used a cheap and cheerful flux pen for this. Care should be taken using this type of flux pen as if you push down too hard on the tip the flux gushes out the pen!

 

Now it is time to solder in the components; I started with the 220pF Ceramic Disc Capacitor (221) This goes where C13 should have originally been before Commodore modified the circuit at the factory. The silkscreen on the mainboard shows you exactly where to place it. 

Below is a picture of where it goes (taken after the modification)

As you can see from the photo, the capacitor is sitting flat against the circuit board; this is good electronics practice. To ensure that the component doesn’t slip down when you turn the PCB for soldering you can gently bend the legs of the component to about 45 degrees whilst holding the capacitor flat on the component side. (see photo below)

Next up is the 100nF Ceramic Disc Capacitor (104); this goes where FB7 was positioned.

 

Again ensure that the component is sitting as flat as possible on the circuit board then solder.

 

Now we come to the trickiest part of this modification; soldering the 470pF Capacitor (471) in place. As this is a new component there are no Vias to stick the legs through; care should be taken to solder the component legs on to the correct place.

One leg of the Capacitor is soldered on to Pin 2 of the Vic Chip; I actually didn’t solder directly on to the Vic Chip as I didn’t want to risk overheating the pin on the chip so I soldered it on to the correct Via of C13 (the 220pF capacitor we soldered earlier)

Below is a photo of the finished mod taken after the capacitor was soldered into place.

As you can see from the photo, I have used heatshrink sleeving to insulate the other leg of the capacitor (the one which has a wire soldered on to it) This is just in case the bare wire/leg of the capacitor short circuits against another part of the PCB when the PCB is secured down to the bottom of the Vic 20 Case.

 

I cut the leg of the capacitor going to be soldered on to C13 quite short as it would be difficult to use heatshrink sleeving on the component leg.

 

I then tinned the end of the cut leg (applying solder to the leg by heating it up and melting solder on to it)

Next up is to solder it on to the correct Via.

Tin the other leg of the capacitor as close to the capacitor as possible then trim the excess leg away; this will reduce the length of heatshrink sleeving you will require to insulate your solder joint for the wire which will go to the output video connector.

Now prepare your piece of wire; I used 10/0.1mm yellow equipment wire as it is nice and flexible (the thicker the wire the less easy it is to solder and route around the circuit board) Thicker equipment wire is also a wee bit more expensive as well (you know how us Aberdonians are; we actually invented copper wire when two Aberdonians fought over a penny they found lying on the pavement… true story ;) )

 

Strip about 5mm of the insulation off one end of the wire; twist together tightly and tin the end. This will prevent fraying of the wire when you actually solder it on to the capacitor leg and it also makes it easier to solder.

 

Now solder the wire on to the capacitor leg; I would recommend you use a Butt Solder joint for this as if you wrap the wire around the leg the solder joint will be wider than it should and you may not be able to use the 1.5mm heatshrink sleeving as it would be too small to slide over the solder joint.

 

A Butt joint is where you solder the wire on to the leg in a straight line; basically line them up in parallel, heat the component leg with the soldering iron and then lay the tinned wire on to the component leg, wait until the solder melts on both the capacitor leg and tinned wire then remove the soldering iron (try not to move the wire or capacitor whilst the solder cools down as this will result in a poor solder joint)

Cut enough Heatshrink sleeving to completely cover the solder joint slide it over the wire all the way to the capacitor then use either a heatgun (as I did) or your soldering iron to shrink the sleeving. Care should be taken doing this as it is easy to melt the wire or in some cases damage the circuit board.

Finally for this mod, we need to solder the other end of the wire to Pins 4/5 of the Video Output Connector. This is pretty straightforward; strip about 5mm insulation off the end of the wire, twist the wires together then tin.

Use tweesers to hold position the wire at the correct place on the circuit board, heat and melt the solder on the Via then slide the tinned wire on to the via creating a good connection. Try and ensure that the wire is lying flat on the circuit board as you do not want it sticking up at an angle.

 

Hopefully the 470pF Capacitor will look like this.

Now it is time to clean up the soldering with Isopropyl Alcohol. I will be expecting another complaint about a funny tasting toothbrush tonight from Mrs Geek ;)

Now all that has to be done for this part of the restoration is test that video output.

As I am planning to further work on the VIC 20, I didn’t completely screw the whole computer together.

Now it was time to test; I used my VIC 20 Data Cassette Recorder to load Trap as I wanted to test everything with the VIC 20 after working on the Mainboard.

 

Here are the results

 

Original Video Output

Modified Video Output

As you can hopefully see, there is a vast improvement in picture quality. The original picture had jail bars and some of the text was a wee bit hazy (especially on the red ‘High Score’ lettering. The modified picture is so much sharper and has no real visible jail bars. I am absolutely delighted with this modification.

Many thanks and much respect go out to Noel’s Retro Lab for posting this modification on Youtube!

On a wee side note; should I wish to return the VIC 20 to its original state, I have bagged and stored away the original components. This should be a relatively simple job as there were no destructive modifications made to the mainboard.

 

Now for Part two of this entry!

 

I am actually quite excited about this part as I have never done it before. I absolutely love learning new techniques and processes so when I noticed the corrosion on the RF Shield I thought that I could do something about it.

 

I could have bought some rust eating gel but that would have been no fun… Instead I turned my attention to Electrolysis Rust removal. Finally I have found a use for something I was shown in Chemistry at school more years ago than I care to remember ;0) I am sure that my old Chemistry teacher would approve!

 

Let’s have a look at that corroded RF Shield again

 Ugghh! Looks completely out of place in my sparkly clean housing!

 

Time to do something about it!

The parts/ingredients needed for the electrolysis rust removal are as follows

 

Baking Soda or Salt

Water

Plastic Tub

Something to secure the Iron anode

An Iron Anode (I used an old screwdriver)

Car Battery

Cables with croc clips (to fit the battery and attach to the Anode and rusted part)

Wire Wool (I used a soap filled pad)

Polishing compound (Optional)

You may want to use gloves as well as it is quite a dirty process.

 

Below is the wiring Diagram

And here is a picture of my prototype setup

 

I filled the old DVD box lid with water about 80% full then put two teaspoons of Bicarbonate of Soda then stirred until completely dissolved. Rather crudely, I placed the screwdriver in the tub and secured it to the side with insulating tape (which wasn’t my best idea ever ;o) ) I connected the positive cable to the screwdriver and the negative cable to the lid of the RF Shield then plugged in the cables to my car battery.

 

I switched on and hoped for the best!

 

Almost instantly I saw the reaction I was looking for

The solution started fizzing and there was a whole lot of action going on at the Anode… It was working!

 

This is a picture after an hour

And after a couple of hours it looked like this.

As a wee side note: it is worth rotating the part 180 degrees periodically as the rust is attracted to the anode better with line of sight.

 

Looks pretty disgusting doesn’t it?

Time to give it a clean. 

Unplug the power first then remove the part.

Not bad at all!

It still looked a bit tarnished but I thought that a scrub with some wire wool would take it up nicely. I also used some polishing compound (see picture)

And here is the result

Looks fantastic!

Now time to build a better electrolysis station.

I used a larger plastic container and stuck an adhesive cable tie base near the top then I secured the Anode (screwdriver) in place with a wire strip (the kind you get on new cables)

Here is a picture of the Electrolysis station MK2

 

I then repeated the process used for the lid of the RF Shield on both the housing for the RF Shield and the metal housing around the edge connector.

 

And after much scrubbing, this is what I am left with!

 

Three sparkly clean parts! Beautiful!

 

But I don’t want to leave things there as after another 40 years, the RF Shield will look exactly the same as it did, so I decided to try my hand at another new process…

 

Electroplating!

 

I have never done this before either and was very surprised at how easy it looked.

 

I have had an agonising wait for parts ordered on ebay but they finally arrived today… time to get to work!

 

What you will need is

 

Vinegar

 

Nickel Anodes, either plates, rods or the very thin anode strips

 

Salt

 

Car Battery (or another power soure)

Connectors

 

Gloves

Some kind of filter if you use the thin anode strips as they break up whilst making the Nickel plating solution.

 

A 3.5 – 5V DC Power Source (I built a crude 5V Regulator with a Diode on the output to give me a little volts drop from the 5V)

Now a wee word of warning… This is a smelly process! Your house will stink of vinegar if you do this indoors.

And on another note; I must apologise to Aberdeen and the whole north east of Scotland for the eruption at Mount Geek at around 7am on Friday Morning. Mrs Geek woke up and exploded! The house was reeking! Some of the things she called me were quite unflattering and I even had to look up some words! I got the feeling that she wasn’t best pleased ;o)

Ohhh, almost forgot, and this is very, VERY important; you should NEVER EVER under any circumstances ask how to spell such words when you try and google them later on… for some reason and I don't know why, this made matters worse... a whole lot worse!

 

Anyhoo, back to the Electroplating!

 

Let’s set up the container

 

Firstly, pour in the Vinegar (I used three 575ml bottles)

 

Next, add the salt (I guess that I used about three tablespoons worth)

 

Then stir until the salt is completely dissolved.

 

Now we come to wiring up the Nickel Acetate production circuit.

I started with the Single strip attached to the negative connector on one side of the container and the 4 or 5 strips connected to the positive connector on the other side of the container. Unfortunately, the distance between the two was too great for a good reaction so I moved them closer together.

I then powered up the circuit; it is worth noting that as I was using quite a volume of vinegar/salt solution, this was going to take some time (four hours in fact) Changes are slow but after around ninety minutes you should have a very faint green tinge to the solution. Also around the ninety minute mark, I found that the 4 strips of nickel on the Positive connector had been completely dissolved into the solution. 

Great it was working!

 

Below is a picture of the dissolved Nickel Strips

I replaced them with another four strips and reconnected the negative wire

I had to replace the Nickel three times in total over the four hours it took to get the Nickel Acetate to what I thought was the correct darkness of ‘green’

Below is a photo of the dissolved Nickel Strips

And below is a picture of the Nickel Acetate after four hours of cooking

As the Nickel breaks down and dissolves in the container you are left with what can be best described as Nickel powder and Nickel Granules lying at the bottom of the container. Obviously that will have an effect if left in the container when we use the Electroplating process.

 

From what I had read about it, it can lie on the part you are plating and will then be plated over leaving you with a rough finish.

 

Time to filter out those Nickel particles.

Place your filter on top of your new container as seen below

Then carefully pour the Nickel Acetate into the new container.

And hopefully you will catch most of the impurities. I think that I will use a paper filter next time as the solution was still a wee bit cloudy for my liking.

Below is a picture of what I managed to collect in my 3D Printer filter.

Next, refill up your old container as we are just about to start the Electroplating process

From what I have read about electroplating with Nickel, it requires a voltage range between 3.5 – 5V DC. As I have a 12 V car battery as my power source I would have to do something about that. I decided to use a L7805 1.5A Voltage Regulator as my main drop down then decided to put a 1N4004 diode in series with the output to drop it down 0.7V (just to be on the safe side)

Below is a picture of my schematic 

 

As I couldn’t wait to make a PCB, I decided to knock one up very quickly. It is a bit Heath Robinson but it did the trick. I was getting a steady 4.5V DC at the output

 

Below is a picture of my Voltage Regulator Circuit

Now it was time to set it all up; refill the original container with the Nickel Acetate, then connect the positive wire to a single Nickel Strip as seen below.

I am not an expert in this but I did read that it is best to try and keep the part being plated moving as the bubbles formed as part of the process can affect the finish so I spent a fair bit of time standing over the horrible vinegary smelling solution either moving the wire to knock the bubbles off or turning the part around so that everything gets plated evenly. The Youtube clip at the end of this entry shows this better than I can describe.

After about an hour in total, I washed each part and dried them. Below is a picture of the result

They weren’t quite what I expected (I was hoping for super shiny) but this was my first time doing this. I have since read that you can buy additives which will give a different finish on the plating.

Having said that, I am delighted with the finish, they look ok and I know that they will not rust the same way they did before (hopefully good for another 40 years!)

 

Now it is time to refit the parts.

 

Starting with the housing for the RF Shield around the VIC chip.

Solder the highlighted Via’s. I recommend you turn the heat up on your soldering iron as it takes a fair bit of heat to get the temperature warm enough to flow solder on the shield pins.

Take care not to melt the wire from the 470pF Capacitor

Next, fit the lid; it simply pushes on

Now, refit the edge connector cover

Turn the board upside down and grab the locking clip with a pair of pliers

Gently twist each locking clip with the pliers to lock the cover in place

And here we have it, a fully restored PCB

Now fit everything together, below is a picture of the bottom of the VIC 20; remember to fit the black bezel for the power, switch and joystick port before screwing it together. Then refit the keyboard and LED connector and finally screw in the final three fixing screws

 

Time to re-test the system, again I decided to load a tape game (just to check full functionality) Wire it up as shown and switch on

Load the game

 

and...

and...

Success!

 

Another restored computer.

 

This VIC 20 has been a real pleasure to work on; it is a lovely machine! Well built and easy to work on and believe it or not the PCB was in much better condition than its younger brother (my C64) I absolutely loved this project!

 

On a personal note, I love learning new techniques; the whole electrolysis and electroplating was completely new to me (apart from when I was being bored stupid during my chemistry lessons at school) but that was about 35 years ago and I am sure that my old chemistry teacher would approve ;o)

 

During this project I have learned

 

VIC 20 Video Modification (thanks to Noel’s Retro Labs)

Electrolysis Rust Removal

Electroplating

 

And as an added bonus; I even learned new curse words (thank you Mrs Geek)

However, I did learn that you should never ask how to spell such curse words!

Thank you for taking the time to read all the way though this entry (it was rather long)

 

If you have any questions or queries, please feel free to get in touch either through the blog or email me directly at

Alleged_geek@aol.com

Also, any feedback, good or bad would be greatly beificial

 

Thank you