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Old 27 September 2019, 02:32   #1
Tony Gunk
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Amiga 500 Issies (Still)

Hello, again.


So, the issues with my rev5 Amiga 500 have yet to subside. Based on the lack of a working keyboard, left mouse button, and floppy drive, I assumed the issues were with one, or both of the CIA chips. Sure enough, my DiagROM was reporting that both CIA chips were failing in all areas. So, I purchased 2 replacement chips, and placed them in my Amiga, with no change in behavior. The computer still exhibits the signs of malfunctioning CIA chips despite both having been replaced. I'm thinking that worst case scenario is that something is damaged on the motherboard, but I'm not certain.


As usual, any help on this matter would be greatly appreciated.
Thanks.

Edit:
How do I upload images to my posts? I'd like to give visuals of what the DiagROM is reporting on my screen, but I'm not sure of how to do so.
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Old 27 September 2019, 02:44   #2
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For pictures, I upload to Imgur and then use the BBcode of the image to link to it.

Post clear and closeup pictures of your motherboard too, top and underneath.
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Old 27 September 2019, 08:54   #3
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Also please resize your pics to 1024 width if you intend on posting them inline with the img tag ... If you are unwilling/unable to resize, then please just paste the url with no tags and we can click on it and have our browsers resize it.
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Old 28 September 2019, 03:11   #4
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https://imgur.com/a/CFcUNG9


Here's some pictures of the motherboard, and the DiagROM's CIA test screen.
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Old 28 September 2019, 10:34   #5
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Please describe the symptoms of your issues again.

In your other post you had stated that it was able to get to the boot screen but could not load a disc? You also mentioned that a pin broke on Paula? What pin and what is the state of that?

Getting back to basics, have you reseated all the socketed chips, and inspected and cleaned the pins and sockets?

You should also get a PLCC extractor tool to do the same for Fat Agnus.

You should also clean your floppy drive read/write heads with isopropyl alcohol; and lubricate the track motor gear.

Please add closeup pictures of the various areas of the motherboard, and of the chips, and of the sockets without the chips in.

I'm not sure what would cause the timings failure of the CIA chips - probably something to do with the clock source. I would also post that screen to the main Commodore Amiga group on Facebook - the developer of Diagrom is on there. There might still be issues with Diagrom and CIA timings tests on NTSC machines.

Last edited by solarmon; 28 September 2019 at 11:08.
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Old 30 September 2019, 04:32   #6
Tony Gunk
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https://imgur.com/a/2boxNaz


The CIA chips featured are the replacements I bought, and not the originals.


The primary issues I'm experiencing are lack of floppy drive functionality (both internal and external), a non-working keyboard, and the left mouse button seems to not work, while the right one does.


A while back, one of the legs on the end of the Paula chip snapped off. However, I have purchased a new one since then.


All of the chips have been reseated multiple times, though I have not properly "cleaned" any of the sockets.


I also took a pictures of the Fat Agnus chip, its socket, and the pin headers for the RAM expansion, in case anything could be wrong there.
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Old 30 September 2019, 10:18   #7
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Hi, thanks for the pictures.

From those pictures, the pins and sockets do look corroded, so you need to get back to basics. You should invest in a wire and fiberglass pen set to clean the pins of the chips and sockets (outside and especially on the inside because of the the sockets - see below), with isopropyl alcohol. At a minimum with a clean toothbrush and isopropyl alcohol.

The Fat Agnus socket contacts look corroded - so clean that carefully, as well as the Fat Agnus chip pins.

The other sockets are single sided, so this can especially cause issue. I would, after cleaning the socket pins, *carefully* bend in the chip pins inwards so that they would press a bit more against the socket contacts. Make sure you especially clean the inside of the chip pins. It could be that some of the pins are not making good contact, especially with corroded pins and sockets.

When you say the floppy drives, keyboard and left mouse buttons don't work, how have you determined this? How are you able to test these? Explain how the machine is booting up - what is on the screen and what is happening with the power LED and caps lock LED?

For the floppy drives, have you cleaned the read/write heads - with cotton bud and isopropyl alcohol? The stepper motor worm gear needs to be clean and lubricate too. And you might need to lubricate the write protect and disk presence sensor too.

Last edited by solarmon; 30 September 2019 at 10:33.
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Old 03 October 2019, 03:15   #8
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The pictures of the CIA chips I gave were of the replacement chips I bought, as I assumed it was the chips that needed replacing. The original chips look much better. However, if the sockets seem to be somewhat corroded, I could invest in proper cleaning materials. When you mention pins, I assume you're talking about the pins on the RAM expansion port? I ask because I'd assume that to be the most suspected spot for corrosion, considering there was a A501 expansion in that slot.


When the computer boots up, it does so seemingly as it should. The power and drive LED's light up as if all is normal, and there's no present caps lock light codes; the caps lock won't light up at all, actually. I determined the keyboard wasn't working when trying to use it with the DiagROM, and I got no response. The left mouse button simply won't do anything, while the right will. As for the floppy drives, the computer does recognize both when I boot from a hard drive, but I cannot access either of the for reading or writing to any of the disks I own (I own a lot of disks). I have not gone through and cleaned the drives yet, however, so I do plan on doing that.
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Old 03 October 2019, 04:49   #9
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Do the drives even click when empty?
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Old 03 October 2019, 07:28   #10
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Quote:
Originally Posted by idrougge View Post
Do the drives even click when empty?


Yes.
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Old 03 October 2019, 07:45   #11
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Quote:
Originally Posted by Tony Gunk View Post
I could invest in proper cleaning materials.
Until you do so then the corroded chip pins and sockets will always be suspect.

Quote:
Originally Posted by Tony Gunk View Post
When you mention pins, I assume you're talking about the pins on the RAM expansion port?
No, I meant the chip pins. I'm not concerned about the expansion port pins at the moment, assuming you don't have anything connected to it.

Quote:
Originally Posted by Tony Gunk View Post
As for the floppy drives, the computer does recognize both when I boot from a hard drive
This is totally confusing now. What hard drive? How is that connected to A500?

Quote:
Originally Posted by Tony Gunk View Post
but I cannot access either of the for reading or writing to any of the disks I own (I own a lot of disks). I have not gone through and cleaned the drives yet, however, so I do plan on doing that.
Looking at your pictures, the floppy power connector does not look right - it is not the normal/expected keyed connector - like this:



It seems just to be header pins - so there is a high chance that you may have connected up in reversed which would have meant you would have sent 12V down the 5V and vice-versa. You may have fried your floppy drives by doing this.

This could be the same for the keyboard. Are you sure you have connected it the right way round? The purple cable/pin should be on the right.

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Old 05 October 2019, 18:08   #12
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I own an original Impact Series 2 A500-HD+ SCSI hard drive expansion for the A500, which I can boot from. The floppy drive power cable is plugged in correctly, however it has been plugged in backwards before, presumably for a long period of time. I was given the computer as "non-working" by someone who had it stored in a cardboard box along with all it's other peripherals, inside his storage shed in his back yard. The keyboard cable also seemed to be backwards for the longest time, but I have corrected that as well. When I first got the computer, I could never get it to boot to the kickstart screen, because the cables were plugged in backwards. Based on this, is it possible that my floppy drive has long since been fried? And if so, could my keyboard, and to some extent, my mouse functionality also be compromised?
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Old 07 October 2019, 10:08   #13
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The keyboard probably survived, the floppy drive usually will fry if you have the power cable plugged in backwards.
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Old 07 October 2019, 11:42   #14
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Yes, the keyboard should not have been affected if it is plugged in backwards - the VCC pin (orange) just gets swapped with the empty pin slot - so it just wouldn't get power.

Are you sure you have it connected correctly? Upload some pictures to show how you've got the keyboard and floppy drive connected.

However, as stated already, until you all get the sockets and pins appropriately cleaned then they will always be suspect.
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