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Amiga computer related discussion => General chat about Amiga topics => Topic started by: ramis77 on March 20, 2010, 10:26:08 AM
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Hi!!
My name is Ramiro Aranda, and I have an Amiga 500 just from yesterday. I am spanish and have 32 years old. I´m not a programmer, but I like video games since I was a child (I had a 16Kb RAM Spectrum). Unfortunately, I have never used an Amiga.
I have no idea in how to deal with the Commodore, so I expect to learn a lot in these forums.
The computer came with a big joystick and more than 200 disks, and I don´t know yet how much memory has installed.
I tried to turn it on last night but my old TV didn´t work, and I could see only the screen in one colour in my plasma TV (with Amiga 520 connected), I suppose I have to get another old-tube TV.
Moreover, the computer has an interruptor near the disk driver, and I have no idea of what activates...
I think I will have to read a lot here!!
Regards,
Ramiro
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Welcome :)
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Wellcome mate!!!
What colout is It? Green?
The switch could be for deactivate the memory expansion, so if It's broken, It could generate a memory error, and It's reflected with a green screen.
Of course, that error could be generated by other causes, like a faulty chip, a bad seated chip, etc...
There are more error colour codes, like grey for a rom problem, so let us know the colour to help you.
The complete error colour code:
Red: Bad ROM
Yellow: CPU Exception before bootstrap code is loaded (faulty CPU).
Green: Bad Chip Ram or Agnus, or any support chip (74LS245, Gary chip... etc.).
Black: No CPU (ouch!!!).
White: No error.
Grey: CPU passed.
PD.: I'm spanish too, I got a speccy 16k too, and I'm 32... Are you from the other side of the mirror??? :P
Saludos.
Edit:
Corrected a mistake and expanded with the general colour codes.
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Thank you for your repplies!
The colour is green. Is it easy to repair?
And what about the switch in the right side of the computer? It seems to have been added making a hole in the case...
to ferix: nice to meet you, I live in Zaragoza.
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I think the switch is for deactivate the internal expansion. Some old (very old) games doesn't work with the expansion attached.
The green screen error could be generated by a bad seated chip, so open your amiga an push on every chip, and try again.
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Welcome aboard, Amiga 500 is almost at the bottom end to begin your entry level of Amiga but you can get some great games for that machine regardless with just 1 megabyte of memory and a 880k disk drive.
Hope you get your Amiga 500 sorted out with the green screen!
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I bet the battery on the expansion RAM has leaked...
Underneath the Amiga there is a trapdoor, pop it open and you will see in there a card. This is the 512k RAM expansion. Pull the card out and see if there is any corrosion near the battery.
Actually unscrew the entire case to get at the 512k card, you will need to pull out the cards wire and switch as well (that switch you said was modded onto the case).
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I have opened the Amiga and:
- You are right, there is a 512 Kb expansion card. At the internal side of the switch there are 2 cables that are solded to the expansion card (they are OK) and 3 cables that go towards the Amiga mainboard (2 of them are desolded from the switch)
- I can see corrosion in the battery
I am going to ask for a solder to fix the cables but I think the computer is going to work only without the expansion... Is it easy to get and replace that battery or maybe I should look for a new expansion card?
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Welcome aboard!
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- I can see corrosion in the battery
I am going to ask for a solder to fix the cables but I think the computer is going to work only without the expansion... Is it easy to get and replace that battery or maybe I should look for a new expansion card?
First, try to boot without the expansion card. If It boots, then take a look at the memory expansion. Some tracks on the pcb could be damaged by the battery leak, so they will need to be repaired.
P.D.:
I forgot It. I'm from La Coruña.
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Welcome!
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Welcome to the world of Amigas! If your 512k expansion is cleaned up and has the battery removed, there's a chance it will go on working (although the clock won't keep the time anymore, no big problem). If you don't want to use the bad quality Composite or RF-out from the A520, you can buy brand new S-Video/Composite adapters relatively cheap. These plug into the RGB port where the A520 is plugged in, but give you a much clearer, sharper image, and all you need is a TV with an S-Video input. You can get them here - http://www.amigamaniac.com and they really help! Using one of these with any CRT TV makes it instantly feel like a big 1084 monitor because of how crisp the display is, and with LCD TVs it's even clearer. It should work with Plasmas as well, provided there's S-Video inputs.
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Bad luck,
I have removed the expansion card and I have the same green screen when I try to boot. I don´t know if I have to do something with the three cables that went from motherboard to the switch (I have tested to unit between them but the result is the same)
Do you think is worth sending to somewhere to repair it?
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Hey, don't give up!!!
I'll help you to fix your amiga.
In the worst case, you can send It to me.
I'll repair It for you, for free, of course. You only pay the shipment and the spare parts. ;)
But first, try to do It yourself.
First of all, carefully lift up all the socketed chips, and reseat them.
Ok, Agnus needs a special tool to be extracted, but you can get It for 4 euros or less.
(http://todoelectronica.com/extractor-integrados-plcc-p-7376.html)
If you need more tips, please tell me. You can send me a PM. I'll answer you... in spanish ;)
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Is it a blank green screen or is it a green-tinted display, showing the Kickstart screen?
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Thank you very much for your help!
Although today I am very dissapointed, I will do my best to repair it!
I´m going to start inmediately to follow your instructions.
I promise to report it!
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It is a blank green screen. I have just realized that at first it is orange but turns into green in less than a second...
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I extracted Denise, Paula, Gary, Odd CIA A & B, and 68000. It doesn´t work yet. Waiting for the special tool to extract Agnus...
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I saw the topic and thought, "Wow, Amiga has been sold again".
Then I read the post and thought it was a lot more interesting :) So "Hi!".
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Green screen can be as result of a bad ram chip too, so try this:
Turn on the computer, and wait for all chips to become warm.
Now, touch every ram chip, and if one of them is too hot, probably It's a faulty chip...
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Hi, Ramiro. Welcome to the Amiga community.
For some system information goto your System volume, then to the Tools drawer, then the ShowConfig icon. It should show Version information, RAM information, and other hardware that is installed. This works on an A1200 and I presume it should be the same for your A500. I'm sure someone here will correct me if the A500 is different.
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At the internal side of the switch there are 2 cables that are solded to the expansion card (they are OK) and 3 cables that go towards the Amiga mainboard (2 of them are desolded from the switch)
Sounds like someone's done the 1MB chip RAM hack, and made it switchable. If those wires have come off the switch lugs, you'll have a very confused Amiga! Even with them on and working, you would need the expansion ram to be working with the switch in one position, but possibly would work without it when the switch is in the other position. (How many positions does teh switch have?) Can you possibly attach some digital photos of your Amiga board, especially where the wires attach to the motherboard?
First order of business is to find the 1MB Chip RAM hack and verify that the wires to the mainboard are in the same locations.
Is it easy to get and replace that battery or maybe I should look for a new expansion card?
If the battery has damaged the card, you may not get it working by removing or replacing it. If actual data bus tracks are damaged, you will need to get another expansion card. These are plentiful as almost everyone had them.
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For some system information goto your System volume, then to the Tools drawer, then the ShowConfig icon.
You would of course need a WORKING Amiga before you could do ANYTHING in 'Workbench'. The ShowConfig util is found in Workbench 2.0 and above.
Once you get your Amiga working, you can move on to bigger things :-D
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thank you all for your replies!
I am going to work, but this afternoon will check the temperature on chips and will take some pics.
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Welcome aboard :)
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Hi, and Welcome!
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I have checked the chips whith the computer turned on and:
DENISE, PAULA, GARY, 68000 and AGNUS heat up, but I think memory chips do not.
I enclose 3 pics:
1) Amiga board general view
http://img267.imageshack.us/i/dscn3202n.jpg/
2) Expansion wires joint to board
http://img691.imageshack.us/i/dscn3203b.jpg/
I tried to join the ends of these three wires between them and it all was the same.
3) Expansion card
http://img222.imageshack.us/i/dscn3204.jpg/
Before turning green, the screen is sometimes orange, sometimes pink for less than a second!!
I have a voltmeter, could it help? Any idea?
Saludos,
Ramiro
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Ok, now I see what is happening.
This wiring is for changing the mapping of the expansion board, from chip to fast.
Now I'm at work, so I can't check It, but what you need is to join the center pin of JP2 with one of the others, but only one, not both.
At first, we will try to boot without the expansion board.
As soon as I can confirm the original position I'll tell you.