Amiga A600 boot black screen

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Trippy1986
Posts: 18
Joined: Mon Sep 06, 2021 12:33 am

Amiga A600 boot black screen

Post by Trippy1986 »

I need some help. I have an A600, I added whdload to the unit but then saw I needed extra memory. I made up a 1mb ram expansion first, plugged it in and booted. Led came one the card but it was just coming up with a yellow or green screen

Removed the unit and noticed a small bridge on the underside of one of the ram chips, I have Spares so I'm going to replace it

But before I went any further I tried booting the Amiga again as stock or with the whdload cf adapter

I'm getting just black screen now, floppy makes no noise and I'm stuck....i'm not sure what I have done. Any suggestions or help would be greatly appreciated
go0se
Posts: 403
Joined: Sun Nov 25, 2018 7:55 pm

Re: Amiga A600 boot black screen

Post by go0se »

Try cleaning the trapdoor expansion connector on the motherboard with IPA and also inspect it (both sides) for any damage or shorts that might have been caused while fitting the chip RAM expansion.

Also were you not asking about flashing the CPLD on a 4MB A600 FAST ram expansion on another thread? The type that sits over the CPU with an inverted PLCC socket?

If you are now getting a black screen on your unexpanded A600 then it is possible that you have shorted or damaged pins on the CPU or cracked a solder joint at the base of the 68000. This is unlikely as they are fairly robust but it is a possibility with rough handling.

Inspect your CPU with magnification for any damage and then clean it thoroughly with IPA.

Also with regards to the solder bridge, why not try removing the bridge on the expansion RAM chip before replacing the whole chip? If it's a bridge between address/data/GND pins it is unlikely to have done any harm. If it is a bridge to VCC then it might* have caused an issue but worth checking by removing the bridge, and then testing again.
Trippy1986
Posts: 18
Joined: Mon Sep 06, 2021 12:33 am

Re: Amiga A600 boot black screen

Post by Trippy1986 »

go0se wrote: Mon Jun 13, 2022 3:07 pm Try cleaning the trapdoor expansion connector on the motherboard with IPA and also inspect it (both sides) for any damage or shorts that might have been caused while fitting the chip RAM expansion.
Thanks, I'll give that a go when I get in
go0se wrote: Mon Jun 13, 2022 3:07 pm Also were you not asking about flashing the CPLD on a 4MB A600 FAST ram expansion on another thread? The type that sits over the CPU with an inverted PLCC socket?
Yes, I've not fitted that yet thought as the two flashers I have I'm having ussuesing flashing it, never flashed a cpld before. Anyone who can fkash then for me or help me to do it would be amazing. I've tried usb blaster v2 and a altera usb programmer, not even sure on what software to use. Like I said im a newbie when it comes to flashing cpld

I've only tried fitting the card upgrade so far
go0se wrote: Mon Jun 13, 2022 3:07 pm Also with regards to the solder bridge, why not try removing the bridge on the expansion RAM chip before replacing the whole chip? If it's a bridge between address/data/GND pins it is unlikely to have done any harm. If it is a bridge to VCC then it might* have caused an issue but worth checking by removing the bridge, and then testing again.
I'll sort that after I resolve the booting issue, but the bridge seems to be underneath the chip, unfortunately these chips sit on a surface rather than through holes. Might just be easier to remove the chip, clean and resolder
go0se
Posts: 403
Joined: Sun Nov 25, 2018 7:55 pm

Re: Amiga A600 boot black screen

Post by go0se »

Trippy1986 wrote: Mon Jun 13, 2022 6:40 pm Yes, I've not fitted that yet thought as the two flashers I have I'm having ussuesing flashing it, never flashed a cpld before. Anyone who can fkash then for me or help me to do it would be amazing. I've tried usb blaster v2 and a altera usb programmer, not even sure on what software to use. Like I said im a newbie when it comes to flashing cpld

There are comprehensive instructions on how to flash the firmware for that expansion, including the suggested software to use, located here :

https://github.com/SukkoPera/OpenAmiga5 ... r/firmware
Danoo
Posts: 249
Joined: Wed Jan 29, 2020 1:25 pm
Location: Queensland, Australia

Re: Amiga A600 boot black screen

Post by Danoo »

A well known black screen fault on the A600 is a faulty/leaking capacitor on the reset line. Maybe the ram board short caused this capacitor to fall over the edge. Can not remember which one off the top of the head, but a quick search of A600 black screen, will point you in the right direction. Just a suggestion, possibly another area to check.
Life is really simple, but we insist on making it complicated - Confucius
Trippy1986
Posts: 18
Joined: Mon Sep 06, 2021 12:33 am

Re: Amiga A600 boot black screen

Post by Trippy1986 »

Yeah I thought that, I actually ordered a full re cap kit so once it's here I'll get test done

Thx for that
Trippy1986
Posts: 18
Joined: Mon Sep 06, 2021 12:33 am

Re: Amiga A600 boot black screen

Post by Trippy1986 »

Danoo wrote: Mon Jun 13, 2022 11:11 pm A well known black screen fault on the A600 is a faulty/leaking capacitor on the reset line. Maybe the ram board short caused this capacitor to fall over the edge. Can not remember which one off the top of the head, but a quick search of A600 black screen, will point you in the right direction. Just a suggestion, possibly another area to check.
I've finally got around to doing this. Boughtva cap kit from AmigaKit

I want to replace the cap on the reset line and test before completing the entire recap

Which cap is on the reset line??

Thanks
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supaduper
Posts: 561
Joined: Thu Nov 08, 2018 12:05 pm

Re: Amiga A600 boot black screen

Post by supaduper »

to help with the diagnosis, the A600 will boot without the U17 ram chip on so just try it with just U16 ram chip on the mobo and this might help as soldering those damn ram chips can be a pain and the A600 mobo is not the best as it hates heat especially round those ram chips.

And the reset cap is C306
Trippy1986
Posts: 18
Joined: Mon Sep 06, 2021 12:33 am

Re: Amiga A600 boot black screen

Post by Trippy1986 »

Interesting my A600 Amigkit cap kit doesn't include C306.....

What's the details for this Cap?

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16637845864464078849454574231642.jpg (255.45 KiB) Viewed 1314 times
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supaduper
Posts: 561
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Re: Amiga A600 boot black screen

Post by supaduper »

Its a small 10uf 35v Capacitor directly above the 555 timer chip
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