Screen fault

[Popopo]

Hi!
Any update?
Photos or details?

[Wicksy]

I'll pm you as I can't upload

[Wicksy]

[quote=stephen_usher post_id=65513 time=
Hopefully it's not the ZX8301 though.
[/quote]

That would be an easier fix for me.

[Popopo]

Hopefully it's not the ZX8301 though.

That would be an easier fix for me.

Better if it is an RAM IC,
trust it.

[Popopo]

I'll pm you as I can't upload

Much better if you post them here,
that way many average users could check them out too, and even notice problems that I could not.

Note:
Maybe it would be helpful for you to use this site to upload photos and share them here:
https://postimages.org/

[Wicksy]

Maybe it would be helpful for you to use this site to upload photos and share them here:
https://postimages.org/

Thanks Popopo.

https://postimg.cc/gallery/XVfXsKg

[XorA]

There is a suspicious modification on the back of that SGC

See the picture for what it normally looks like. I think that SGC has been modded for 5V running with an aurora!

[Wicksy]

Yes an Aurora and Qubide were sold by the same seller.

How much or what damage has it likely done?

[Popopo]

Yes an Aurora and Qubide were sold by the same seller.

How much or what damage has it likely done?

It is hard to predict.
Usually, the first component in blow up is a RAM IC, what may protect the rest of the system from the short. That works taking all the energy from the power line and that way protecting the rest of over current/voltage.
But it hardly be asserted without checking it out.

When you have some ICs socketed and 2 QLs.
From NO POWER in your damaged QL:

Very Important Part
Firstly, you need to check shorts between Vcc and GND lines in the main QL board.
Secondly, look for shorts from Vcc memory line, to the GND line, and later to each ADDR and DATA line.
Thirdly, repeat the same with the CPU, ZX8301 and ZX8302.

In case you don't know how to do it, we can manage it by conference or with a video on Y2B

If there ARE NOT shorts then:
1. replace one by one FROM Faulty QL to the Working QL. That way mark with a label what is OK and what not.
STOP and tell us results.
2. If there were any damaged IC, put them all apart (damaged) and replace them from Working QL
2.1 Be aware that ZX8302 has two resistor over it with a wire soldered to another IC. If you hesitate about desoldering and soldering skills, do not continue with it.

In one moment, you will need to check the power regulators, the most important in your case is the 5v one. So in your shoes, when I have removed the ICs I would messure the powerlines to know if there are all fine in range or not.

Usually the IC24 is a badass hard to die, so I would not worry too much about it. Same goes about CPU, but never bad to check them.

There is always a risk about to test some good components into a faulty QL, but if you proceed with the checking as I have described (very important the first part) the risk is very very very low.
That would be the easiest way to test by yourself.

[XorA]

Unfortunately "untested" is eBay speak for "I did test but it didn't work!"

Annoyingly probably the SGC is also damaged by 9v.