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Disclaimer: The following information documents my own use of 'Retrobrite'. Follow these instructions at your own risk. If you apply this stuff to your rare Commodore 65 and ruin it, don't say you weren't warned!
You may have noticed that light colour plastics on old micros can go orange. Is this dirt? No, it's down to exposure to UV light, sometimes decades ago. Can you reverse this? Well yes, with a technique called Retrobrite.
I'm not going to go into the science here, but rather document my own first experiments with it. Naturally I wouldn't want to risk anything valuable with such an experiment but I had a broken Amiga PSU case going spare. It had really bad yellowing (I guess the heat didn't help) so it seemed an ideal candidate.
First up you need to wash your plastic and remove any paper labels. The PSU was filthy and I had to get every last piece of dust and dirt off of it. I also had to remove the paper label. Washing in soap and water alone didn't get it off but a healthy dose of isopropyl alcohol did.
One clean Amiga PSU. Look at the bit on the left piece that had been covered for 22 years by a label. That's the original colour! Can we get it back to that colour in one afternoon?
This is what you'll need to Retrobrite an Amiga PSU.
1 Clean Paintbrush
2 Ziplock Freezer Bags
Rubber gloves and appropriate eye protection
Be Blonde 40% Hydrogen Peroxide Solution (available from Superdrug).
Something to work on. I'm using a padded envelope here as it has plastic inside so nothing can soak through.
I'm using Be Blonde which is a hair colouring product which is known to contain exactly the correct ingredients for Retrobrite. Be wary of using other products, they may have additives that could damage the plastic. Be Blonde also has a paste like consistency which makes it easy to paint onto the PSU. It contains 40% hydrogen peroxide which is the strength that has been proven to work best. Be sure to buy the right one as different strengths are available in the same container.
So here we go. Slap on the Retrobrite generously. You don't want it to dry out. Get it in every nook and cranny. Be careful though, it'll burn your skin and bleach anything in sight.
Ouch! I forgot to wear gloves. And people put this in their hair! Don't be an idiot like me, wear gloves! And make sure you wear old clothes as well. It will bleach anything it touches!
Both halves of the PSU are smothered in Retrobrite. The bags are sealed up and left in sunlight. You need to keep an eye on them and keep topping up the paste. The paste must NEVER dry out!
90 minutes later I am still topping up and turning the case every 15 minutes. I'm doing this on a late August day with occasional cloud cover in the UK. Adjust the procedure for your own climate. As I said before you need to keep a close eye on them to prevent drying out.
3 hours after I started I put the PSU case back in the sink and carefully dispose of the ziplock bags. I note my paint brush is now fully blonde! I throughly wash the Retrobrite off of the case making sure it is out of every last corner of it.
The original is on the left and the results 3 hours later are on the right. It's fair to say after just 3 hours the case isn't as good as new, but it has considerably lightened. Unfortunately despite my best efforts, part of the case did show some minor blooming which means the paste did dry out.
Not bad for a first go though. The case is now much closer to the original colour as seen on the label section. Another treatment and it will improve further.
My strong advice with Retrobrite is to not only be very careful but to experiment on spare bits of plastic first. I did this as an experiment and currently have no intention of treating any of my micros, but I did want to see if Retrobrite worked and if it could yield any results on something as orange as my broken Amiga PSU.
I did this experiment 8 months ago and the PSU case has neither changed colour since nor has it become brittle or cracked. So the change to the plastic seems fairly stable.
Try it for yourself at your own risk. Your results may vary.
The Amstrad CPC, the computer on which the Oliver Twins programmed the first Dizzy game and was also my own first home computer. 27 colours, a BASIC arguably better than that of the BBC micro and integrated cassette recorder or disc drive*. The all in one package for the family home of the 1980's.
Today there are lots of CPC's to choose from on auction sites such as Ebay. But which one to go for? And why do some models have very high "buy it now prices"?
The original CPC (1984 to 1990) came in three flavours.
CPC 464 - Tape based with 64k. Cannot connect to a floppy disc drive without the Amstrad DD1 interface. This rules out using a SD card solution for loading. However you can still load from a PC or audio device using a car cassette adaptor.
CPC 664 - Short lived 64k disc based model. Rare as hens teeth. Keyboard membranes are prone to failure although can be replaced.
CPC 6128 - The Rolls Royce of the original range. 128k, built in floppy drive. The machine to own.
A CPC 464 with CTM 644 monitor
The 1990 models offered extra hardware capabities including 4096 colours and DMA sound along with new Amiga style cases. Little software took advantage of this.
464 Plus - New model of the original 464.
6128 Plus - Again new model of the original 6128 but has no tape input.
GX4000 - Cartridge based console. We'll cover this separately in another article.
Every CPC came with either a colour monitor or a green screen (later black and white with the Plus models). Do you feel you need a CRT monitor for the authentic experience or are you happy plugging into a modern LCD?
The monitor houses the power supply so if you want to have a machine without a monitor you will require a 5 volt power supply (positive centre) with at least 2 amps with a 2.5mm plug. If you have a disk based model you'll also need a 12v supply with a 2.5mm plug with a gender changer.
Common with all systems, if you want to play light gun games you will need the monitor as light guns do not work with LCDs. Amstrad did produced an official lightgun in conjunction with Virgin Mastertronic. There is also the Trojan Lightphaser for the Plus machines. However the selection of games is extremely limited in both cases.
Additionally if you do not purchase a monitor you will require a RGB to SCART cable so the CPC's RGB signal can be displayed on any television with a SCART input.
Retailers on Ebay do sell complete kits to connect to an LCD TV. You are advised to check the quality of the power supplies before purchasing.
As with all these things there are many sellers on certain auction sites trying to sell CPC's for hundreds of pounds. However the 664 aside, costs should be reasonable. A boxed 464 without monitor cost us £15 last year and we recently purchased a full 6128 system for £25 as a local pick-up (although a good 6128 can command £50). Plus units fetch more but don't be fooled by "But It Now" chancers claiming they are worth £300. They aren't. Be patient, there are still bargains to be had!
CPC's are quite hardy and not a lot needs doing to them (see "Gotchas" below). A new drive belt and half hour of cleaning does not justify a seller charging hundreds over the odds because he's "restored" it.
None of the costs above take into account any extra bundled software. It is up to you to assess the value of any included software, joysticks, etc.
Newer revisions of CPC have the striped Amstrad logo on them. This was introduced around 1988. There are changes internally as well but these make no difference to the average user.
Later 464's have slightly different keys and may have Spanish writing in addition to the English on the side.
Watch out for German models (earlier models will be labelled Schneider). They have different connectors on the back (Centronics rather than edge connectors). Not a massive problem but if you go for an SD card solution such as an HxC you will need to get the right connector.
The CPC was the number 1 selling micro in France for many years. Amstrad localised the CPC to have a French AZERTY keyboard. Naturally some of these have made their way to the UK over the years. There is no software compatibility issues but if you are used to a QWERTY keyboard then you may find an AZERTY keyboard annoying.
The oldest CPC's are now 30 years old. Amstrad have a bit of a reputation for some of their equipment being poorly built but this doesn't extend to their computers. As far back as 1989 the CPC was voted the most reliable home computer by UK computer dealers as reported in New Computer Express. However at 30 years old there are a few things to look out for.
Drive belts inside disc drives WILL need replacing. Don't wait for the dreaded "Disc Missing" message and funny noises. Cost is about £2 for the part and they are easily available on Ebay. Don't be tempted to use a rubber band, you'll wreck the drive. Use the CPC Wiki guide and for heavens sake don't lose the write protect pin!
Likewise tape belts are also starting to age and while not as fragile as the disc drive belts it is advised to replace them. Again easily available and cost about £2.
Clean the tape heads with a lint free cotton swab and isopropyl alcohol. Do not use an abrasive head cleaning cassette (as often given away on the front of computer magazines). They are like running sandpaper over the delicate mechanism!
If you've purchased a monitor be aware that any CRT of that age is a timebomb. At some stage you will end up trying to source an old fashioned TV repair man to replace some capacitors, or worse, the flyback transformer. Do not under any circumstances attempt to open or repair the monitor yourself. CRT's contain dangerous voltages and can retain them for a long time after they are disconnected from the mains.
The CPC Plus machines (and GX4000) rely heavily on a custom ASIC chip for their function. If this chip is damaged you have next to zero chance of getting a replacement. So be very sure any Plus machine you buy fully works.
If purchasing a monitor do undo the plug and check the wiring. I've seen a few CTM monitors with poor/loose connections inside the plug (often due to the plugs strain relief failing). Also check it has the correct fuse as detailed on the back of the monitor. You are dealing with a 30 year old CRT so the correct fuse is essential. It will protect you and your monitor.
Watch out for rip off postage prices for people trying to sell monitors. A well packaged CTM 644 monitor costs £13 to send via UPS on 48 hour delivery and collected from your door. I know this as I've sent one myself (Feb 2015). Don't let people charging rip off postage fees profit from your desire to own a CPC with monitor
If you have a monitor, always turn it on first, then the computer. When finished, turn the computer off then the monitor.
Never remove a floppy disc until the drive has stopped spinning.
Auto fire on joysticks doesn't work on a CPC. Sorry!
If you have a system capable of supporting a disc drive out of the box (not the 464 or 464 Plus) consider getting an HxC floppy drive emulator and load all your software in from SD card.
The built in speaker is awful. Turn it down with the volume control and plug an amplifier into the 3.5mm jack on the side. The socket doesn't work with headphones, it requires an amplifier.
On a 464 (or 664 or 6128 after typing |Tape ) pressing control and small Enter at the same time will give you a shortcut to loading.
On a Spectrum you Load"", on a CPC you Run"" .
In BASIC hold down shift and then use the curser keys to move a second curser around the screen. Then press copy to copy whatever text the second curser is over.
Join the CPC Wiki forum for friendly and helpful advice from long standing CPC users.
Loads! Far more than it is given credit for. Among others check out:Sorcery + (disc only)Head Over HeelsFeudChase HQSuper Robin HoodNorth And SouthGet DexterRobocop
Above all, enjoy your new Amstrad CPC. It's a great complete computer system!
* We're using the Amstrad and Acorn spelling of "disc" with a c in this article.