Thursday, March 15, 2018

The Amstrad ALT-286 - Repairs, FDD Not Working, Battery Damage



The Amstrad ALT-286 is a very nice machine, its a mix between the TOSHIBA T3100/20 and the SHARP PC-4500.

It shares same technology like the two mentioned above but the display its superior due to the fact it came on the market almost 3 years after the Toshiba and Sharp. Even if it was more budget oriented the computer has a lot of features and the quality build is impressive.

I got this computer from a local sales site and the computer was stated as working. The amount requested was 699 LEI, that means in EUR 155. I called the seller and he was OK to sell it for 40 EUR. The original post:



Short technical description:
Computer: ALT 286
Processor: 80286
Screen: VGA LCD 640*480 Pixel
Reverse by programming plus contrast and brightness switches
Graphics: Cirrus Logic
Memory: 4x 1024 KB Max
Harddisk: 20 to 60 MB
FDD Drive 720 KB FD-235HF
Extensionslots VGA
ISA
AT Keyboard
FDD Floppydrive
System: DOS 3.3 and DOS 5.0
Printerport Centronics
Serial Ports 2x9 Pens. One for mouse
Weight: 7 KG


Issues:

The Computer had better days, the HDD spins up but OS is not found, and the FDD is not working for sure as it has a very unlikely sound when booting and it does not spin the floppy disk. I will take apart the computer these days and I will replace the HDD and the FDD unit. The FDD unit can be replaced but there is a custom mod you have to do on the Floppy cable. I found an interesting article of someone that replaced the original unit with a standard one. I will start working and get back to you with the details.



Step 1 Disasembly

Remove the screws from the bottom \ back and aside.

Bottom view


Step 2 Remove top cover

To do this you need to have your screen in OPEN position and then just lift the top cover from the bottom and put the cover on a side like in the photo. The display cables are pretty long so you can leave it like that or remove the cables to fully take apart.

Inside #1


Step 3 Remove stuff

EXTENSION MODULE

For this you need to remove the 4 screws in the picture and just lift up the socket on the right top of the module. (this is not mandatory but you need space to remove the FDD)

Extension module\ Bios chip (on the back)
View on RAM and BIOS (the sticker came off, don`t get it into the light as its UV sensitive and it will erase data\I had put a black sticker on that)

REMOVE FDD UNIT

Remove the 5 screws and lift up the FDD unit. 

Floppy Disk Removed

REMOVE ALUMINUM COVER

Next part is to remove the aluminium cover (note that this cover has also the role to spread the heat of the chips)


Battery leaked on the MOBO :(


Even if the battery looks in sharp condition you have to remove it. If it hasn`t leaked it will so just replace it or cut it off. I just removed it cause I use this computer rarely so I just don`t care the setup will forget the HDD config or the clock...


REMOVE METAL FRAME

Next part is to remove the metal frame like in the picture below:

Metal Frame


BATTERY DAMAGE REPAIR

Battery damage on mobo
I had used some Isoprylic Alcohol to clean the damage and vinegar ti neutralize the acid area.

Now this looks better! Lets get some soldering done!
Nice and Clean
The capacitor seems fine, so I just resoldered but its legs were damaged so I used some extra wire... a lot of extra wire :)

You have to agree it looks artistic...  ;))) be careful on the polarity (the capacitor has a black mark for negative)

Now lets get back to the FLOPPY part 


Basically you need a standard 3.5 FDD, I got one with the DS jumper so for me its very easy to make the mod. Basically I just have to remove 5 7 9 11 wires stated in above diagram and get the +5V on the new FDD unit.

IF YOU DO NOT HAVE THE DS OPTION

Cut 10 and 12 and reverse 10-12   \ 12-10

OLD VS NEW Floppy design

I was able to change the plastic front ornament from one to another, they are both made by TEAC company.
New FDD with the old grey front ornament
I think the picture above is very descriptive and for those who are technical people will manage easy.
Where my hand is is the connector that fits the mobo.

1 is the green wire \ use 11 for +5V and cut down 5, 7, 9, 11

I had put some isolating tape just to make sure the wires won`t touch something inside the computer.

Use any tape you have and place on both sides

Now Place the red wire on the +5V connector on your new Floppy Disk.
+5V on first inner pin


TESTING

Now place the FDD cable and the pin on +5V and boot up your PC!


MS-DOS 5.0 is now loaded!

NEXT STEP - Sit back and enjoy your vintage laptop!



If you have any questions, leave a comment.
Don`t forget to check out my museum`s Facebook Page and WebSite




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