Sega Game Gear Capacitor Change

So after having a half stripped Sega Game Gear rattling around in my work drawer for a few years, I decided it was time to order a Cap Kit and get it running in its former glory…

So as a starter, split the Game Gear in two:

Remove the metal shield overlapping the audio board:

Remove the Audio Board:

And prep for surgery. Looks like one or two of the caps on here have already been changed at some point in the past:

Game Gear Audio Board stripped of caps. Unfortunately two of the solder pads came away during the process. They are very fragile so carefully does it:

And now new caps fitted. Also ran two pieces of instrument wire to bridge the connections from the missing solder pads:

A quick test and audio from both the in-built speaker and the headphone socket is blasting out nicely.

The next step… The main board!

PSP Go on 65” 4K Sony TV

Yup. Use your PSP Go as a full game console with separate controller and even connect it to your TV.

What you will need:

1. PSPGo
2. PSPGo TV component lead (head to eBay)
3. PS3 controller
4. PS3 (only once to initially connect the controller to the PSP)

So first you need to turn on your PSP Bluetooth and use your PS3 to connect the controller to the PSP. 

Once the Bluetooth is initialised to the PSP, you won’t need to use the PS3 again.

Then plug the PSP into the TV and off you go.

PSPGo on 65” 4k Sony BT linked to PS3 controller…

Space Invaders on the Sony PlayStation / PSX / PSOne / PS1

You know how it is. It’s a Saturday afternoon. The only game console you can lay your hands on is a Sony PlayStation and the only game that will do is classic arcade Space Invaders. What are your options?


  1. ” Space Invaders – The Original ” (Japan Release 1997)
A collection of four different classic Space Invaders flavours / romsets along with dip switch settings, screen zoom and rotation and a VS Battle Mode. Looking at the files on the game CD, it appears that the original romsets are on there so this is emulated Space Invaders in its rawest form. Just like being at the arcade in the day.


  1. ” Space Invaders 2000 ” (Japan Release 1998)
A collection of four different classic Space Invaders flavours / romsets along with….. Deja Vu anyone? This release adds a timed attack mode and the two player modes on the original games that the previous release lacked. The “2000” in the title is I believe the price in Yen, not a reference to the coming new millennium at the time. This release also has a non Space Invaders option on the menu which seems to allow you to play some train simulators from “Darius & GO!2”. I tried this briefly but being non-fluent in Japanese, it was hard going.


  1. ” Simple 1500 Series Vol. 73 – The Invader ” (Japan Release 2001)
A collection of four different classic Space Invaders flavours / romsets along with….. Here we go again! The same line up as Space Invaders 2000 with a different colour title screen and an extra game squeezed in, 3D Space Invaders.
The menu screen and the 3D Space Invaders game included are very reminiscent of the Nintendo Virtual Boy release “Space Invaders Virtual Collection” which included a 3D Space Invaders game. See the comparison pictures below.
“It’s Worth Noting….”

It is worth noting that you can play original arcade Space Invaders on the PlayStation Space Invaders remake / reimagining aka Space Invaders X in Japan. Enable “Select level” code and successfully complete level 00. Hold Right when choosing 1P or 2P game to play classic Space Invaders.


It is also worth noting that you can play several variations of original arcade Space Invaders on the PlayStation using Anthony Ball’s excellent arcade emulators “The Space Invaders Project”, “The Galaxian Project” and “The Phoenix Project”. A collection of the roms that these emulators run is on the Retrocoder Arcade Collection available here and includes:


  • Space Invaders
  • Space Invaders Pt II aka Space Invaders DX
  • Super Earth Invasion

Arcade Classic Game Collections on the Sony PlayStation / PSX / PSOne / PS1

Ok so it doesn’t quite rival MAME… but between these Sony PlayStation arcade collections there are over 100 arcade classics. With Sony PlayStations going for a dime a dozen and so many ways of picking up cheap second hand games, it won’t cost a fortune to get a good arcade collection up and running, and its all nice n legal!


Williams Arcade’s Greatest Hits
Williams Arcades Greatest Hits Front
The Games:
  • Robotron : 2084
  • Defender
  • Defender II
  • Joust
  • Sinistar
  • Bubbles
The Extras:
  • Williams introduction
  • Media library of photos, fliers and memorabilia
  • The inside story for each game
  • Media clips of the people involved


Midway Presents Arcade’s Greatest Hits – The Midway Collection 2
The Games:
  • Blaster
  • Joust 2
  • Splat
  • Burger Time
  • Spy Hunter
  • Moon Patrol
  • Root Beer Tapper
The Extras:
  • Trivia quiz on each game


Midway Presents Arcade’s Greatest Hits – The Atari Collection 1
The Games:
  • Asteroids
  • Missile Command
  • Battle Zone
  • Centipede
  • Tempest
  • Super Breakout
The Extras:
  • The golden age of Atari
  • Media library of photos, fliers and memorabilia
  • The Inside Story for Each Game


Midway Presents Arcade’s Greatest Hits – The Atari Collection 2
The Games:
  • Gauntlet
  • Marble Madness
  • Paperboy
  • Road Blasters
  • Millipede
  • Crystal Castles
The Extras:
  • Gallery for each game – Flyers, Hints and sketches


Atari Anniversary Redux
The Games:
  • Asteroids
  • Asteroids Deluxe
  • Battlezone
  • Black Widow
  • Centipede
  • Gravitar
  • Missile Command
  • Pong
  • Space Duel
  • Super Breakout
  • Tempest
  • Warlords
The Extras:
  • Video Interviews with Nolan Bushnell
  • Excerpts from “Pheonix: The Fall and Rise of Video Games”
  • Photo Gallery of Atari Memorabilia


Midway Arcade Party Pak
The Games:
  • 720
  • Klax
  • Rampage
  • Smash TV
  • Super Sprint
  • Toobin
The Extras:
  • History of Each Game


Konami Arcade Classics aka Konami Arcade Gallery
The Games:
  • Pooyan
  • Scramble
  • Yie Ar Kung Fu
  • Rock n Rope
  • Circus Charlie
  • Shaolins Road
  • Super Cobra
  • Road Fighter
  • Time Pilot
  • Gyruss
The Extras:
  • History of Each Game


Namco Museum – Volume 1
The Games:
  • Pacman
  • Rally X
  • New Rally X
  • Galaga
  • Bosconian
  • Toy Pop
  • Pole Position
The Extras:
  • Virtual Museum Containing Game Info and Memorabilia


Namco Museum – Volume 2


The Games:
  • Super Pacman (Not Japanese Release)
  • Xevious
  • Mappy
  • Gaplus
  • Grobda
  • Dragon Buster
  • Bomb Bee (Japanese Release Only)
  • Cutie Q (Japanese Release Only)
The Extras:
  • Virtual Museum Containing Game Info and Memorabilia


Namco Museum – Volume 3
The Games:
  • Galaxian
  • Ms Pacman
  • Dig Dug
  • Phozon
  • Pole Position 2
  • The Tower of Druaga
The Extras:
  • Virtual Museum Containing Game Info and Memorabilia


Namco Museum – Volume 4
The Games:
  • Pacland
  • The Return of Ishtar
  • The Genji and Heike Clans
  • Assault
  • Ordyne
The Extras:
  • Virtual Museum Containing Game Info and Memorabilia


Namco Museum – Volume 5
The Games:
  • Metro Cross
  • Baraduke
  • Dragon Spirit
  • Pac Mania
  • The Legend Of Valkyrie
The Extras:
  • Virtual Museum Containing Game Info and Memorabilia


Namco Museum – Volume 6 / Encore
The Games:
  • King and Balloon
  • Motos
  • Skykid
  • Rolling Thunder
  • Wonder Momo
  • Rompers
  • Dragon Sabre
The Extras:
  • Virtual Museum Containing Game Info and Memorabilia


Nichibutsu Arcade Classics
The Games:
  • Moon Cresta
  • Crazy Climber
  • Frisky Tom
  • SF-X
  • Toms Strike Back
  • Crazy Climber 85
The Extras:
  • Various Flyers and Memorabilia


Irem Arcade Classics
The Games:
  • 10 Yard Fight
  • Zippy Race
  • Kung Fu Master
The Extras:
  • Appears to be a video walk-thru of Kung Fu Master


Capcom Generations – Volumes 1 to 5


Four Disc Release
Two Disc Release
Single Disc Releases
Capcom Generations 1 – Wings Of Destiny
The Games:
  • 1942
  • 1943
  • 1943 Kai
The Extras:
  • Art and Illustrations
  • Tips
  • Cast
  • Secrets


Capcom Generations 2 – Chronicles of Arthur
The Games:
  • Ghosts and Goblins
  • Ghouls and Ghosts
  • Super Ghouls and Ghosts
The Extras:
  • Art and Illustrations
  • Tips
  • Cast
  • Secrets


Capcom Generations 3 – The First Generation
The Games:
  • Vulgus
  • Sonson
  • Pirate Ship Higemaru
  • Exed Exes
The Extras:
  • Art and Illustrations
  • Tips
  • Cast
  • Secrets


Capcom Generations 4 – Blazing Guns
The Games:
  • Commando
  • Gunsmoke
  • Mercs
The Extras:
  • Art and Illustrations
  • Tips
  • Cast
  • Secrets


Capcom Generations 5 – Street Fighter Collection 2
The Games:
  • Street Fighter II: The World Warrior
  • Street Fighter II: Champion Edition
  • Street Fighter II Turbo: Hyper Fighting
The Extras:
  • Art and Illustrations
  • Tips
  • Cast
  • Secrets


Reference List of All Games in Alphabetical Order


  • 10 yard fight – IREM Arcade Classics
  • 1942 – Capcom Generations 1
  • 1943 – Capcom Generations 1
  • 1943 Kai – Capcom Generations 1
  • 720 – Midway Arcade Party Pak
  • Assault – Namco Museum 4
  • Asteroids – The Atari Collection 1 & Atari Anniversary Redux
  • Asteroids Deluxe – Atari Anniversary Redux
  • Baraduke – Namco Museum 5
  • Battle Zone – The Atari Collection 1 & Atari Anniversary Redux
  • Black Widow – Atari Anniversary Redux
  • Blaster – The Midway Collection 2
  • Bomb Bee – Namco Museum 2 (Japanese Release Only)
  • Bosconian – Namco Museum 1
  • Bubbles – Williams Arcade’s Greatest Hits
  • Burger Time – The Midway Collection 2
  • Centipede – The Atari Collection 1 & Atari Anniversary Redux
  • Circus Charlie – Konami Arcade Classics
  • Commando – Capcom Generations 4
  • Crazy Climber – Nichibutsu Arcade Classics
  • Crazy Climber 85 – Nichibutsu Arcade Classics
  • Crystal Castles – The Atari Collection 1
  • Cutie Q – Namco Museum 2 (Japanese Release Only)
  • Defender – Williams Arcade’s Greatest Hits
  • Defender II – Williams Arcade’s Greatest Hits
  • Dig Dug – Namco Museum 3
  • Dragon Buster – Namco Museum 2
  • Dragon Sabre – Namco Museum 6 / Encore
  • Dragon Spirit – Namco Museum 5
  • Exed Exes – Capcom Generations 3
  • Frisky Tom – Nichibutsu Arcade Classics
  • Galaga – Namco Museum 1
  • Galaxian – Namco Museum 3
  • Gaplus – Namco Museum 2
  • Gauntlet – The Atari Collection 2
  • Ghosts and Goblins – Capcom Generations 2
  • Ghouls and Ghosts – Capcom Generations 2
  • Gravitar – Atari Anniversary Redux
  • Grobda – Namco Museum 2
  • Gunsmoke – Capcom Generations 4
  • Gyruss – Konami Arcade Classics
  • Joust – Williams Arcade’s Greatest Hits
  • Joust 2 – The Midway Collection 2
  • King and Balloon – Namco Museum 6 / Encore
  • Klax – Midway Arcade Party Pak
  • Kung Fu Master – IREM Arcade Classics
  • Mappy – Namco Museum 2
  • Marble Madness – The Atari Collection 2
  • Mercs – Capcom Generations 4
  • Metro Cross – Namco Museum 5
  • Millipede – The Atari Collection 2
  • Missile Command – The Atari Collection 1 & Atari Anniversary Redux
  • Moon Cresta – Nichibutsu Arcade Classics
  • Moon Patrol – The Midway Collection 2
  • Motos – Namco Museum 6 / Encore
  • Ms Pacman – Namco Museum 3
  • New Rally X – Namco Museum 1
  • Ordyne – Namco Museum 4
  • Pacman – Namco Museum 1
  • Pacland – Namco Museum 4
  • Pacmania – Namco Museum 5
  • Paperboy – The Atari Collection 2
  • Phozon – Namco Museum 3
  • Pirate Ship Higemaru – Capcom Generations 3
  • Pole Position – Namco Museum 1
  • Pole Position 2 – Namco Museum 3
  • Pong – Atari Anniversary Redux
  • Pooyan – Konami Arcade Classics
  • Rally X – Namco Museum 1
  • Rampage – Midway Arcade Party Pak
  • Road Blasters – The Atari Collection 2
  • Road Fighter – Konami Arcade Classics
  • Robotron : 2084 – Williams Arcade’s Greatest Hits
  • Rock n Rope – Konami Arcade Classics
  • Rolling thunder – Namco Museum 6 / Encore
  • Rompers – Namco Museum 6 / Encore
  • Root Beer Tapper – The Midway Collection 2
  • Scramble – Konami Arcade Classics
  • SF-X – Nichibutsu Arcade Classics
  • Shaolins Road – Konami Arcade Classics
  • Sinistar – Williams Arcade’s Greatest Hits
  • Skykid – Namco Museum 6 / Encore
  • Smash TV – Midway Arcade Party Pak
  • Sonson – Capcom Generations 3
  • Space Duel – Atari Anniversary Redux
  • Splat – The Midway Collection 2
  • Spy Hunter – The Midway Collection 2
  • Street Fighter II: Champion Edition – Capcom Generations 5
  • Street Fighter II: The World Warrior – Capcom Generations 5
  • Street Fighter II Turbo: Hyper Fighting – Capcom Generations 5
  • Super Breakout – The Atari Collection 1 & Atari Anniversary Redux
  • Super Cobra – Konami Arcade Classics
  • Super ghouls and ghosts – Capcom Generations 2
  • Super Pacman – Namco Museum 2 (Not Japanese Release)
  • Super Sprint – Midway Arcade Party Pak
  • Tempest – The Atari Collection 1 & Atari Anniversary Redux
  • The Genji and Heike Clans – Namco Museum 4
  • The Legend Of Valkyrie – Namco Museum 5
  • The Return of Ishtar – Namco Museum 4
  • The Tower of Druaga – Namco Museum 3
  • Time Pilot – Konami Arcade Classics
  • Toms Strike Back – Nichibutsu Arcade Classics
  • Toobin – Midway Arcade Party Pak
  • Toy Pop – Namco Museum 1
  • Vulgus – Capcom Generations 3
  • Warlords – Atari Anniversary Redux
  • Wonder Momo – Namco Museum 6 / Encore
  • Xevious – Namco Museum 2
  • Yie Ar Kung Fu – Konami Arcade Classics
  • Zippy Race – IREM Arcade Classics


“It’s Worth Noting….”

Its worth noting that there are some top homebrew arcade emulators for the Sony PlayStation.
The most notable of these is the “Retrocoder Arcade Collection” by Anthony Ball of Double Dutch Designs / Sinister Soft. This collection comes from Anthony’s three arcade emulation projects: “The Space Invaders Project”, “The Galaxian Project” and “The Phoenix Project”.
Each project emulates the specific stated hardware which then allows any associated roms that worked with that hardware to be compiled into a PlayStation executable.
24 of the best games that are emulatable (Is emulatable even a word??) from Anthony’s work are contained on the “Retrocoder Arcade Collection” which is available for download from here.


Sony PlayStation 2 / PSTwo / PS2 with built in games

I’ve had a few good geeky afternoons with one of my old fat ps2’s.

First I installed Free MCBoot and a selection of PS2 apps (ulaunchelf, OpenPS2loader and HDLoader) onto a standard PS2 memory card.Next using Popstarter and a 32Gb USB2.0 USB memory stick, I got my fave PlayStation games running with no need for any disc of any kind to be inserted and no need of any modchip. 

Basically you make an ISO (.cue and .bin) from your original game disc on a PC, then use CUE2ELF to convert the ISO to a .vcd file. Copy to USB stick, plug into PS2 and then use popstarter and ulaunchelf to run.

Then using an old ide hard drive and the ps2 network adapter, I got my fave ps2 games running from hard drive too.

Plug the drive into a PC using a USB to IDE adapter and then use WINHIIP to format the drive PS2 style and add your original PS2 games from disc to the IDE drive. Fit drive into the PS2 drive bay and then use HDLoader or PS2Open Loader to run the games.

In short, there is no need for the DVD drive any more, and the laser in it always was the weak link. Also there’s no need for any mod chip as all the code/apps are on the memory card.So the result, a ps2 with all of my favourite PlayStation and PlayStation 2 games built in.

Rumours of the PSOne and PSTwos death have been vastly exagerated!!

Sega Game Gear Repair II – Second Game Gear Stripped Down

The second of my Game Gears that I’ve stripped down is the single ASIC version. This has a higher wet capacitor count on the motherboard by one.

Having checked the capacitor values out against the list on the link on the previous Game Gear Repair post I again found some differences which may just be down to what capacitors were thrown in there at the time.
C4, C14, C42 and C11 are all 10uF / 16V on my one rather than 10uF / 6.3V. Whilst this is probably donw th 16V ones being cheaper than 6.3V ones at the time it may be best to err on the side of caution and replace with 16V ones, this could have been a mod due to 6.3V ones leaking excessively.


This one does show some minor signs of wet capacitor leakage. Whilst it hasn’t actually spilt over the motherboard and caused corrosion, there is some sweatiness around a few of the caps.

I now have one final Game Gear to open and check before I have to decide on the actual caps I’m using as replacements. I currently thinking dry alluminium electrolytic ones to negate having to replace them all again in 15 years time!

Sega Game Gear Repair – Game Gear prepped for surgery!!!!

After reading some wise words about Sega Game Gear Repair Here I now have one of my three game gears stripped and ready for surgery.
From the link above you can see that Sega Game Gears have two different motherboard versions, one with a single ASIC chip and one with two ICs. The wet and potentially leaky capacitor count is also different depending on the version you have. It seems that the first one I’ve picked to perform the capacitor transplant on has the 2 ASIC chip motherboard (top half of picture) which also has one less capacitor to change, however before I start ordering capacitors by the bucketfull I need to check the other two to see which revisions they are.
I will make a couple of corrections to the capacitor list for the two ASIC version motherboard, the capacitors are situated very tightly together but C38 should actually read C37 and C14 should read C6. Looking at the motherboard itself I can see how the author of the link above would get these things easily confused!
I should point out at this stage that I found no actual evidence of leakage from any of the capacitors but the Game Gear itself had started to display some evidence of capacitor drift. Switching it on from cold would just get you a blank screen for a few seconds followed by it switching itself back off again. The second switch on would just get you a blank screen, off and on a third time and it leapt into life.
The bottom half of picture shows the inside of the back of the game gear with power board lower right and audio board lower left.
This Game Gear has had previous surgery on the audio board as when I first got it the audio from the external speaker wasn’t working. This also turned out to be a capacitor issue. Two of the caps on the audio board start to try out after a while causing loss of sound so if you’re carrying out the repair on the motherboard, it’s probably a good idea to change the audio board caps as well for some non wet types.
I’ll mention the 4.5mm Gamebit head screw here. The Sega Game Gear itself is held together by 6 standard phillips head style screws and a “Gamebit” head screw. This 4.5mm gamebit head screw is basically a screw with an odd shaped head that a standard screwdriver won’t undo and is used as an anti-tamper screw to stop you opening your Sega Gamegear. Nintendo and other manufacturers also use the gamebit so if you take consoles apart regularly it may be worth investing in one. Just google 4.5mm gamebit and you should be able to get one no problem.
If you want to save yourself a fiver and have a decent set of thin nose plyers then it is possible to get the gamebit screw off by holding the screw head in the pliers very tightly and then gently turning the screw head round. BE ADVISED!! If you don’t do this very very carefully then you can damage both the Game Gear case and the Screw head so it’s off of your own back which method you chose and I accept no responsibility for damage etc done by people too tight to pay a fiver for the 4.5mm gamebit socket!!

Sega Gamegear saves the day….

Ah the dilema…… A gorgeous sunday for lazin on the beach and England Vs Germany footie on at 3pm. What to do!

Well at last the retro game console collection came in handy for something other than retro gaming. Whilst looking doubtfully at the 42″ HD Plasma and wondering how good the picture would be on the beach running from a generator, I suddenly remembered that I have 3 Sega Game Gears and one of them has the TV plug in.

A quick rummage around in the loft and a lot of batteries later and….






Hey presto! Portable TV.

Looking back now I needn’t have bothered ha ha, but before I witnessed the diabolical sham known as “The Match” I lay there basted up with oil, a cool box full of Sol Lager and wedges of lime, a 25 degree sun, water lappin at my feet and with the footie on and was in paradise….for the first few minutes anyway ha ha

What did become obvious to me was that out of the three Sega Game Gears that I have, two of them are suffering major display issues and one minor issues. I have had to repair the audio on all three Game Gears already replacing all of the capacitors on each audio board as they dry up over time and you lose external sound.

It appears from the symptoms I have (dark screen, switches itself off a few times, distortion on screen etc etc) that I now have to replace about another 10 capacitors on the main board as well as a potential acid mop up job from where the old capacitors are leaking their dielectric out. For some reason wet caps were used when Sega Game Gears were built. I’m replacing them all with dry electrolytic ones so that I don’t have to replace them again!!

Oh by the way, while I was up in the loft I was accosted by a sinister gathering..





ARGHH!!! It’s Attack Of The Omnibots!!!! From Right to left: Omnibot, Omnibot 2000, Hearoid and Robie Sr and in the background is Robosapien 2.

These poor guys have been up in the loft for a while. Omnibot, Hearoid and Robie Sr work perfectly. Omnibot 2000 works partially with the exception of voice over from the remote control and I haven’t got around to repairing it yet. Omnibot has box and all accessories (tray etc) so does Hearoid. Robie Sr is just himself and Omnibot 2000 has the motorised tray although I stripped it down to clean it and have only 3/4 assembled it again. Another guy project on my list!! Which reminds me, I must some pages to the website for these fellas!!

Commodore Amiga CD32

This came down from the loft a while back for a clean and functional check.

I thought I’d take a few pics of it up and running:

The Beast Itself.


Bios Screen


A battered up box


The precious contents


A part of the included paperwork


Two controllers. The eagle-eyed of you will notice that the D-Pads are different. This is because the original design on the right was due to be shipped out as it was, but feedback from testers slating the D-Pad design meant a last minute change of sticking a more directional pad on top of the original design. In the case of the right hand controller, this fell off and was lost some time ago.


More paperwork


The product labelling on the bottom of the unit.


Game time! Loading up Myth.


Myth mid game.


Amiga CD32 Rear ports. From left to right:

On-Off switch / Power Input / RF Tuner Output / S-Video Output / Composite Video Output / Left Audio RCA Output / Right Audio RCA Output.

Amiga CD32 Side ports, from left to right:

Controller 1 or mouse input port / Controller 2 or mouse 2 input port / Aux Input port.


Close up of the animal itself with top loading CD deck open.


Close up with lid closed.

Why is diagonal movement faster than straight movement in old arcade games / 8 bit computer games

I am talking bout real old skool games here, like early 80’s arcade stuff and old 8 bit computer games, but on a lot of them if you had a guy on the screen and you ran straight up, down, left or right you’d move slower than if you moved diagonally.

The issue sounds pretty odd but it’s easily answered and can be proved using Pythagoras Theorem.

If you push the left button, your guy on the screen moves 1 pixel to the left say, and if you push the up button your guy moves 1 pixel up the screen. Pretty straight forward yes.

Now if you push left and up at the same time then your guy moves up-left diagonally. This means he’s moved one pixel left and one pixel up in one move. The actual diagonal distance he’s travelled isn’t 1 pixel though, it’s actually just over 1.4 pixels, just like if you had a right angled triangle and the two shorter sides were 1 metre each then the hypotenuse would be just over 1.4 metres.

This means distance wise that every three straight the guy has travelled 3 pixels, but every three diagonal movements the guy has travelled over 4 pixels, hence why running diagonally gives you an advantage in old computer and arcade games, although usually the enemies had the same diagonal advantage too.

How to fix it? Well when you move diagonally, instead of shifting the guy one to the left and one up, shift him 0.7 to the left and 0.7 up and this will make the hypotenuse about 1. Of course ths screen itself can only display in whole pixels and will round up but as long as you don’t round up the actual x and y co-ordinates of the guy then he’ll skip a move every so often which slows him down to normal pace.

So why wasn’t this built into old arcade and computer games….Well there are three possible reasons:

1. It just wasn’t noticed to start with. (Unlikely)
2. It was noticed but people couldn’t be arsed to add the extra code to make it right.
3. Due to limited memory, there wasn’t enough space to add the additional code so programers just lived with it.