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Offline AmigaBrunoTopic starter

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Amiga A1200 green screen after extensive repairs
« on: October 23, 2022, 03:25:48 PM »
My Amiga A1200 recently came back from a repairer after being rained on through a skylight and having a thorough refurbishment including re capping, replacing the broken RGB port and checking that everything was working again after being rained on and ending up covered with gunk. I didn’t actually see the state of the motherboard myself because I never managed to remove the RF shielding. This rusty shielding has now been removed.

Unfortunately, after setting up, then using my Amiga A1200 for only about two hours after these repairs, all of a sudden the screen went bright green!

At the time, the things that were attached to my Amiga were an 8Mb RAM expansion from Amigakit, an IDE extension cable and CF card, as well as a very old 1970s style Atari joystick and a Gotek which didn't have any USB stick plugged into it.

I soon found a thread on a forum about this green screen which said it was a RAM error. I followed their advice to disconnect as many things as possible. I unplugged the CF HDD replacement, but that didn’t work. I ended up by disabling the RAM expansion with a jumper, then removing the expansion altogether, but nothing I did would stop the green screen from being displayed! I didn't unplug the Gotek.

I’ve recently started attending meetings at a repairs workshop where they’ve mentioned surface mount technology and they’re even trying to repair an ancient looking toaster.

It seems that the worst case scenario is for me or someone else to open my Amiga A1200 case again, locate the RAM chips on the motherboard, desolder them, then replace them with working RAM chips, but I don’t know how I could check in advance that they’re working.

There may be more simple techniques for curing this problem. What should I do next?


 

Offline F0LLETT

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Re: Amiga A1200 green screen after extensive repairs
« Reply #1 on: October 23, 2022, 04:34:22 PM »
If you can get hold of some diagnostic roms, that will tell you if its chip ram at fault.
Diagoroms can boot using fast ram from ram card even if chip ram is faulty.

Other than that, as you said replace the ram.
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Offline AmigaBrunoTopic starter

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Re: Amiga A1200 green screen after extensive repairs
« Reply #2 on: October 23, 2022, 06:59:44 PM »
I already know it's the Chip RAM at fault because I removed the Fast RAM! Why should I waste money on diagnostic ROMs which I don't even know how to use?
 

Offline kolla

Re: Amiga A1200 green screen after extensive repairs
« Reply #3 on: October 24, 2022, 07:41:28 AM »
So what are you asking?
You already know it’s the chip ram chips, but you don’t know which chip, and I suppose you don’t know how to replace them anyways, so perhaps the next to do is to send the board to someone who has the skills.

The diagrom is for free btw, provided you have an eprom flasher and some compatible chips.

http://www.diagrom.com/
B5D6A1D019D5D45BCC56F4782AC220D8B3E2A6CC
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A3000/060CSPPC+CVPPC/128MB + 256MB BigRAM/Deneb USB
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A1200/Blz1260/IndyAGA/192MB
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A1200/Blz1230III/32MB
A1200/ACA1221
A600/V600v2/Subway USB
A600/Apollo630/32MB
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CD32/TF328
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Offline F0LLETT

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Re: Amiga A1200 green screen after extensive repairs
« Reply #4 on: October 24, 2022, 09:33:12 AM »
I already know it's the Chip RAM at fault because I removed the Fast RAM! Why should I waste money on diagnostic ROMs which I don't even know how to use?

Use Diagroms, to see which chip is faulty. It still may of course not be the chip ram. As other things related to chip ram can give green screen.
Quote from: Hungry Horace
Resolute and Industrious Grand ruler of the yellow people and the Ultimate Amiga Empire
Ultimate Amiga Network (Home of SONY PSP Amiga Emulator and AMOS Factory)

Quote from:  He who shall not be named
"Chris is that you!!!"
My all time favorite quote.
 

Offline AmigaBrunoTopic starter

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Re: Amiga A1200 green screen after extensive repairs
« Reply #5 on: October 24, 2022, 03:24:18 PM »
My Amiga A1200 has only just been returned from a repair job which lasted nearly 2 months and two weeks. Do you really think I want to send it away again straight after that?!

I don't know which chip is causing the problem. The next stage is to open up my Amiga again and find out if I can see anything obvious. I can also take some pics and post them on here to find out if anyone can see anything wrong with it.

I've been involved with a repairs workshop, which should be able to help me.

What makes you think I've got an EPROM flasher or that I know which chips are compatible with Diagrom? I see that these Diagroms are sold on eBay anyway!
 

Offline F0LLETT

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Re: Amiga A1200 green screen after extensive repairs
« Reply #6 on: October 24, 2022, 10:48:35 PM »
Why are you being aggresive. We are just offering advice on what to do/try.

As its also been subject to water damage, the fault could also be any where. I remember repairing a laptop, which had been submerged in water.
It was left to dry out completely, upon testing it, it would not post. No water was visable, person ended up scrapping it.
3 months later, stipped it down, for something to do, removed CPU and low and behold, there was water trapped in socket. Cleaned it up and it booted and worked perfectly.

This is just another example of what it could be, remember yours is not a common break down or cap leakage.
Maybe there is still some water ingress, may sound crazy, but in my example, after 3 months of being sat there, there was still water under CPU.
Your may have some ingress under one of the chips, who knows until its looked at.
« Last Edit: October 24, 2022, 10:49:58 PM by F0LLETT »
Quote from: Hungry Horace
Resolute and Industrious Grand ruler of the yellow people and the Ultimate Amiga Empire
Ultimate Amiga Network (Home of SONY PSP Amiga Emulator and AMOS Factory)

Quote from:  He who shall not be named
"Chris is that you!!!"
My all time favorite quote.
 

Offline AmigaBrunoTopic starter

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Re: Amiga A1200 green screen after extensive repairs
« Reply #7 on: October 25, 2022, 09:53:49 AM »
My A1200 has already had extensive repairs. I've sent an email to the repairer and had a reply. This basically says that no one can repair it unless they know about Amigas in particular. The repairer has given me a one year guarantee, but this will be voided if anyone else works on the board.

My plan now is to unscrew the casing, take a few pics, looking for anything that may have fallen onto the board, take some pics, then send them to the repairer. After this, I may have to send my Amiga A1200 back to him. I've just asked him how long I may be without it.



« Last Edit: October 25, 2022, 12:33:01 PM by AmigaBruno »
 

Offline HGC

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Re: Amiga A1200 green screen after extensive repairs
« Reply #8 on: October 25, 2022, 07:03:31 PM »
Why not get yourself an Amiga 500 or Amiga 2000?  They are much better made and are higher quality.  Do you actually NEED an Amiga 1200?  If so, why?  Remember, the Amiga 500 and 2000 computers are real Amiga computers.  The Amiga 1200 is an Amiga clone.  SMT boards are not meant to be repaired.  When one goes bad you are suppose to throw it into the garbage and buy a new one.  When my Amiga 1200 computers go bad, I will dump them on eBay.  I will not waste my time repairing them.  Especially when I have Amiga 500 and Amiga 2000 computers.  If they go bad, I repair them, because they are worth repairing.  But, so far, I have NEVER had any problems with any of my Amiga 500 or Amiga 2000 computers.  These computers have the high quality thru-hole motherboards, and they are built to last.  They also have higher quality disk drives and power supplies.  I have often said this, but, nobody seems to listen:  The Amiga 600, 1200, and 4000 computers are poorly designed, low quality pieces of garbage.  Why do you think Americans refused to buy them.  So, Commodore was forced to sell them to the European market.  Remember, the Amiga 500 and the Amiga 2000 was Commodore's number one selling and most popular Amiga models, and most of them were sold in the United States.  So, my advice is, throw that Amiga 1200 computer into the trash dumpster.  Then buy an Amiga 500 or an Amiga 2000 computer.  Trust me, you will be glad you did.   :)
« Last Edit: October 25, 2022, 07:07:10 PM by HGC »
 

Offline F0LLETT

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Re: Amiga A1200 green screen after extensive repairs
« Reply #9 on: October 26, 2022, 12:59:37 PM »
Wow, Im at a lose.

A600, A1200 and A4000 are garbage. Completely disagree.
If you can't repair SMT tech, thats no reason to condem it. It wasn't poor design by commodore, its was new poorly developed caps. Remember SMT caps were a new thing at that time. These leak and cause 95% of the faults seen on these machines. Unfortunately the OP's board had been RAINED on. Not sure how you can put that down to poor quality. Send me all your boards, I will fix them if you think they are garbage.

Its not Americans never wanted them, we all know it was down to marketing. Europe had people like Dave Pleasence, who gave us the awesome packs.
In europe it was just marketed better.


Why not get yourself an Amiga 500 or Amiga 2000?  They are much better made and are higher quality.  Do you actually NEED an Amiga 1200?  If so, why?  Remember, the Amiga 500 and 2000 computers are real Amiga computers.  The Amiga 1200 is an Amiga clone.  SMT boards are not meant to be repaired.  When one goes bad you are suppose to throw it into the garbage and buy a new one.  When my Amiga 1200 computers go bad, I will dump them on eBay.  I will not waste my time repairing them.  Especially when I have Amiga 500 and Amiga 2000 computers.  If they go bad, I repair them, because they are worth repairing.  But, so far, I have NEVER had any problems with any of my Amiga 500 or Amiga 2000 computers.  These computers have the high quality thru-hole motherboards, and they are built to last.  They also have higher quality disk drives and power supplies.  I have often said this, but, nobody seems to listen:  The Amiga 600, 1200, and 4000 computers are poorly designed, low quality pieces of garbage.  Why do you think Americans refused to buy them.  So, Commodore was forced to sell them to the European market.  Remember, the Amiga 500 and the Amiga 2000 was Commodore's number one selling and most popular Amiga models, and most of them were sold in the United States.  So, my advice is, throw that Amiga 1200 computer into the trash dumpster.  Then buy an Amiga 500 or an Amiga 2000 computer.  Trust me, you will be glad you did.   :)
« Last Edit: October 26, 2022, 01:01:08 PM by F0LLETT »
Quote from: Hungry Horace
Resolute and Industrious Grand ruler of the yellow people and the Ultimate Amiga Empire
Ultimate Amiga Network (Home of SONY PSP Amiga Emulator and AMOS Factory)

Quote from:  He who shall not be named
"Chris is that you!!!"
My all time favorite quote.
 

Offline AmigaBrunoTopic starter

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Re: Amiga A1200 green screen after extensive repairs
« Reply #10 on: October 26, 2022, 05:02:43 PM »
I got an Amiga A1200 computer because it's full 32 bit, and it has a lot more colours than the Amiga A500 or Amiga A2000. I originally started with an Amiga A500. I like to do artwork, so I can use the extra colours and screen modes using Deluxe Paint versions with AGA. There are also AGA games which the Amiga A500 and Amiga A2000 can't run, so how are they better? The lack of Commodore publicity and marketing for the A600, A1200, and A4000 in the USA is why they didn't sell many of those computers there. I've also seen some episodes of the series "The Computer Chronicles" and read some articles where they  were talking about the Apple II, IBM PC and compatibles, and Apple MacIntosh as "standards" in the USA and people didn't want any more computers added to that line up. THe Amiga A1200 isn't a clone, because it was made by the same company as the older Amigas and can run the same software, so long as the software followed the guidelines published by Commodore Amiga Inc. The boards were designed to be repaired, but originally came with technical support in case they broke down. Nowadays SMT boards are more common or even normal.   
 

Offline miggyretro

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Re: Amiga A1200 green screen after extensive repairs
« Reply #11 on: October 29, 2022, 02:57:13 PM »
I have 3 A1200’s and a A4000. There great machines. Easy enough to to maintain. Would love a AA3000+ machine.
 

Offline kolla

Re: Amiga A1200 green screen after extensive repairs
« Reply #12 on: October 31, 2022, 08:36:39 PM »
A German is funny and everyone is confused :)
B5D6A1D019D5D45BCC56F4782AC220D8B3E2A6CC
---
A3000/060CSPPC+CVPPC/128MB + 256MB BigRAM/Deneb USB
A4000/CS060/Mediator4000Di/Voodoo5/128MB
A1200/Blz1260/IndyAGA/192MB
A1200/Blz1260/64MB
A1200/Blz1230III/32MB
A1200/ACA1221
A600/V600v2/Subway USB
A600/Apollo630/32MB
A600/A6095
CD32/SX32/32MB/Plipbox
CD32/TF328
A500/V500v2
A500/MTec520
CDTV
MiSTer, MiST, FleaFPGAs and original Minimig
Peg1, SAM440 and Mac minis with MorphOS
 

Offline HyAmi

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Re: Amiga A1200 green screen after extensive repairs
« Reply #13 on: November 01, 2022, 05:59:26 AM »
You mean Doomy is still Doomy?  ;)
As far as I remember, our good ol' Doommaster lives in the US.

A German is funny and everyone is confused :)
 

Offline vince_6

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Re: Amiga A1200 green screen after extensive repairs
« Reply #14 on: November 04, 2022, 08:56:53 PM »
My A600 had the same problem after repairs.
In my case, I just cleaned the chip ram chips with IPA and a toothbrush.
Had some soldering leftovers there.
Then I pressed the chips down with my thumb.
Doesn't sound like a professional advice, but worked for me...
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