PC-Playstation 2 Hybrid

[chedabob]

like the idea. you should fit a watercooling block over the drive, or around the gel packs to keep it all cool.

[justblair]

Update:

Been spending the day learning how to build pcbs. Have been using ExpressPCB. At first the whole pcb design thing seemed difficult, but now I seem to have got the knack of it.

Here is the pcb I have come up with so far. It has three functions...

Thermometer
Monitor ID
signal pass through
Power regulator.

One it holds the maxim 1668 controller. Thats on the top right, of the board in the piccie... It will be top left when I have printed it on acetate and turned it over... To the right of it the thermometers will plug in. They will be made from transistors.

Next underneath is just a pass through for the psone screens signalling. Thats the lines running left to right (or is it right to left?) accross the board.

Under that and to the left is a 24LC21 eprom chip. This is going to be programmed with the correct settings to force the matrox GPU to speak to the psone screen. Will mean I wont have powerstrip running anymore.

To the right and below of the 24LC21 is a power regulating circuit that will give the 7.5v that the psone screen requires. It's using a the LM350T regulator and is designed to hand out up to 3a so it should be OK

My mental fragility was exposed as I desperately tried to work out what pins to connect, the pcb will be reversed on one plane when it finally prints. Ended up printing someone elses maxim based circuit onto acetate. This gave me a chance to try out the toner transfer method. I used a laser copying onto injet acetate. I tried a sheet full of circuits one at a time to try out various techniques. I got the best results heating it up real hot, then running it under cold water. The accuracy was good, but I want to try photoresist as well.

Got a 650 watt halogen OHP sitting. Might try that to see if its any good for exposing the PCB. I will hopefully try that tomorrow.

Oh and goof of the Day, went out to buy an injet cartridge. Needed a HP56, cam home with a 26 (24 squid). I knew which one I was after (I used to manage a pc shop, so I know many printers cartridges off by heart). I just plain read it wrong on the box. I only noticed it when I ripped the box open! No refund...

If anyone out there wants to critique my PCB design I will not be in the slightest bit offended. Its my first go at one. In particular, should I be filling in the ground plane? I gave it a try, but it didn't look as pretty... Not sure that a very scientific reason not to!.

Got a couple of more traces to tidy up, then I'm off to bed.

***Edit****

Forgot, I also modded my Matrox graphics card. Removed the VGA socket from the back of it. By using a saw to cut it in half while still on the card, I now have 15 header pins on the inside of the case. Will solder wires to them, which will plug in to the VGA signal inputs on this pcb. (Fingers crossed)

[justblair]

Update...

Had a very good day today.

Tried out the photoresist technique for making PCBs. I can recomend this technique for noobs to PCB manufacture.. Its so much easier to get a good print on the board than the toner method.

Here is the setup I used. I have an OHP which uses a 650w halogen lamp. This was going to be my method of exposure. First of all I inkjeted two copies of the circuit. I also added a test bar to the top of it. This had two functions. One to let me try a test strip, to determine my exposure time. Secondly it was to ensure that the two sheets of acetate were lined up correctly.

***Edit*** I should have mentioned that I removed the Fresnell lens before begining. The Fresnell would leave dark rings on the image. I have looked round the intermwebby, but noone else seems to use OHP's for this... I may have hit onto something here, it seemed obvious to me.

This photo is me getting ready to make a test exposure. The card under was supposed to be for cutting out the light. I intended to move it every 30 seconds to expose more of the board. When I turned the OHP on however light shone throught the card. I used some very thin alu sheet instead.

The rest is pretty boring, I just followed the instructions on the beginners kit I got from Maplins.

At the end I had a nice PCB

The camers still is rubbish for the closeups. There is a little pitting on 4 of the 0.5' tracks. This was cause i smudged the negative.

in this photo you can see the less shiny area where the pitting is worst. There is a hole in fact, but by good fortune it occured on the ground plane where I had widened the track.

Tested everything first by holding it against the lamp, then by multimeter. All is well.

Now for an admission... This was my second attempt. My first had scratches on it which cut several of the tracks. The mistake I made was when I was agitiating the developer with the plastic tweezers from the kit. I thought I would hurry it along. What I learned was that the photoresist layer is very fragile. Just brushing it with the tweezers is enough to damage it...

I didn't expect to get it right the first time so hey ho.

I'm in a quandry. Do I reprint my negs, and make a third attempt, or be happy I have a working PCB and move on. I'm thinking the latter, the imperfections are really not that noticable. I think I will drill it and use it. At least then if I mess up the drilling, I still have a spare photo board to make another.

Comments as always are welcome...

[GT40_GearHead]

this is so cool
i never known you could make boards like that, the only method i know is painting the tracks(with paint) on a copper plated board, after the paint has dried you dip the board in some kind of acid, and you are left with only the copper under the paint, you then remove the paint and dril the holes........ but this so... so.......

[justblair]

this is so cool
i never known you could make boards like that, the only method i know is painting the tracks(with paint) on a copper plated board, after the paint has dried you dip the board in some kind of acid, and you are left with only the copper under the paint, you then remove the paint and dril the holes........ but this so... so.......

This process is very similar to what you know already. The last stage I did was to bath the board in the acid. The only difference in the photo resist method is that you use boards that have a photo sensitive film.

The bath you see in the right of the pictures is the developer. The photo resist board has a film on it, when light activates it it changes the chemical composition. The developer strips off the changed part of the film to reveal the tracks. Then you bath it s before.

It really is a lot easier than I thought it was going to be. The closest thing I have done to it in the past is black and white film developing (when I did a photography course at school.)

Normally you would use UV light to activate the film, but a halogen bulb gives off some UV. The sheer brightness of the halogen makes up for the fact that only a small part of its spectrum is UV.

Something I forgot to mention in my previous post. Prior to exposing the board I removed the Fresnell lens from the OHP. If you dont do this, I imagine you will get rings on your board.

[GT40_GearHead]

can you post a link or tell where i can find the kit ???
it would be great for my project

[justblair]

I got mine in my local elcetronics store. Maplins. Kemo is the brand name on the kit.

However you dont need to buy it as a kit. You can but the stuff seperately (I dare say it would be cheaper.)

The kit I used had...

A plastic tray
A pair of plastic tweezers (it has to be plastic, the etching solution is highly corrosive to metal)
A sachet of developer
A sachet of Etching Solution.
A selection of 3 PCB boards (one photoresist, one double sided, one single sided)

I bought an extra photoresist board, which I split in three. Two for PCB,s one as a test strip.

There are loads of tutorials on the web.. Google diy photoresist pcb. you will get instructions on how to do it. Some mention making your own photoresist layer. i dont see much point in that if your doing a one off. Pre-prepared photoresist boards dont cost much more than standard boards. Then you get a probably better board with less hassle.

Just one of many tutorials

[GT40_GearHead]

great just great
made a quick bookmark, i will read it first thing in the morning
thx for the info, i might need to make my own photoresist layer, i live in romania, it in eastern europe, ex comunist country it was until 1989, so you can imagine that it has a lots a catching up to do

[justblair]

I dare say that you can get the stuff posted from one of the European mail order companies. I have been to a few ex soviet states (including Romania albiet only passed through on a train) and most things are available if you look in the right places.

[GT40_GearHead]

no blood way, you actualy pased trough here!!!
what did you visited ?