News:

Printed Amstrad Addict magazine announced, check it out here!

Main Menu

Apricot Portable LCD issue

Started by Toundrik, 11:09, 20 March 19

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Toundrik

Hi everyone !

Does anybody have some experience with an Apricot Portable ? More precisely, the LCD isn't working anymore.  :'(

Thanks !

Bryce

Is it completely blank or just very dim or missing lines?

Bryce.

Toundrik

It started to get dimmer and dimmer, and then nothing.

I must had that I don't own this Apricot, it belongs ton one of my friend but he can lend it to me in case there's something to check. He also possesses the schematics of the computer.

Bryce

Do you have the knowledge/skills and equipment to fix it? If so we can go through what needs to be done.

Bryce.

Toundrik

I was able to replace the AMSDOS IC with a PARADOS in a 6128, I can deal with resistors and capacitors. I own AN8008 multimeter (thanks to your advice in the hardware category).
I don't own a scope but I can look for one if needed since I'm willing to learn.
If you think this issue needs far more advanced skill/experience, just tell me, it's ok, I'm not overconfident  :D

Bryce

Well we can give it a try...

The fact that it faded away means that it's most likely a capacitor that has failed. However, you should always start by checking voltages.
On J10 (12way connector to the LCD) you should read 5V across pins 9 and 10. This is most likely ok, otherwise the entire computer wouldn't work, but check it anyway. Then check the voltage across pins 11 and 10. This should be -12V and between any of the pins 1 to 8 and pin 10 there will be data at some point during booting, so these will probably measure somewhere between 0 and 5V while data is being sent. If all of these are ok, then we need to look at the LCD PCB, which is unfortunately not included in the schematics, but a photo might be enough.

Bryce.

Toundrik

I can do that as soon as he lends me the Apricot and I get all my stuff, so around March 30th, I'll keep in touch on this thread.

Many thanks for your time !

Bryce

No problem. My guess at the moment is that a capacitor on the -12V rail has failed, but we'll find out later. If I don't reply to the thread, send me a PM in case I have missed it.

Bryce.

Toundrik

Feedback so far : with Bryce's help, we manage to find an issue with the 5V rail on the main board. We find 3.8V on the input, so there must be a shortage somewhere. Next step is to remove a capacitor in order to check the voltage. Problem is my soldering iron is not powerful enough (11w) to melt the solder on the PCB.... so I probably need to buy a new one  :doh:


I will post some pictures soon

Bryce

Nope, 11W won't work on a power rail with any decent amount of copper pour.

Bryce.

Powered by SMFPacks Menu Editor Mod