Amiga 500 intermittently reboots for no reason!

[circlip]

Hi all,

Aussie Amiga newbie here!

I put a post in the introductions section, but can't find it now.

Anyways, I have just bought a used Amiga 500 setup with "the lot" sold as an "as is" auction on ebay. No software for it yet, but I'm going to hopefully buy WB1.3 next week.

I have turned it on to see a nice "insert WB 1.3" screen, but occasionally it will reset itself. Sometimes it will do it a few times in a row, sometimes I can leave it for 5 minutes without a hitch, sometimes after the 5 minutes it'll do it's reset thing again. Also the "Caps Lock" key is sometimes flashing. As I have no WB yet, I have no way to test the keyboard, so I don't know if the keyboard is OK.

Does anyone have any idea of which part I could replace? Power supply, main unit, or motherboard? I can easily get these from ebay and other sources here in Australia.

I've tried shaking the power supply, and the connection to the main unit is fine, I've tried shaking the keyboard unit, fine too.

Any ideas anyone?

Circlip.

[circlip]

Wow guys, very quick replies! Thanks!

No extra ram cards, and I opened my A500.

Is it true that A500's have bcakup batteries like pc's do? I couldn't find one, and there is no battery corrosion anywhere, so I guess that's a good thing.

I did find the floppy power cable a bit out, but I could've knocked it, so I just pushed it back in.

I also tried to gently press a few of the major chips, in case of a bad contact or whatever.

I put it all back together, and haven't seen any "resets" but next week when I start using it for real, I will then know. I tried a couple CTRL + Amiga + Amiga, and still ok, tried a few power off + on again, fine.

Thanks very much guys, I will let all know if I run into trouble next week when I'm actually doing stuff with Workbench 1.3

Actually, one more thing.... is the rapidly flashing CAPS LOCK key a problem though? It will do it sometimes, and sometimes it's steadily on.

Circlip.

[circlip]

How do I isolate them Defender? Does that mean my keyboard could be useless when I get it going, or just a weird Caps Lock light?

Circlip

[circlip]

Hmmm... just booted up again, and it's still doing the reset thing. Do you guys think I should shell out for a new keyboard unit, or is there a few other things I could try?

Thanks for all your help on this....

Circlip.

[circlip]

@ TjLaZer

Hmmm... don't know if it's the KB itself, but I  meant replacing the WHOLE THING (keyboard that houses everything else inside), would cost about 50 bucks on ebay, and I'd have to go money borrowing, lol.

Shame that my nearest Amiga repairs shop in Sydney NO LONGER supports Amiga. :boohoo: So I'm stuck either figuring out what's wrong, or buying another whole unit, and keeping this one for spare parts.

[circlip]

Well,

I ahd another go, and shook the PSU a bit. It sounds like it has something rattling inside, and I can feel something big shifting in there.

Is it safe to open the power supply with it unplugged without electrocuting myself or something?

@ Jope: Sorry about the Keyboard mistake, I just called it a "keyboard unit" maybe I should call it a "main unit" or something, or A500 unit next time?

@weirdami, NZ couldn't be as bad as Papua New Guinea or Indonesia with their power outages, I've lived in both, annoying when chatting or working on an important file!! :crazy:

The rattling in the PSU sounds like a small loose screw or something.

[circlip]

I've never received so much help from a forum before guys, so thanks for all your hints and tips! We shall get this thing going somehow!

Hi DrDekker.

I plugged it directly into the Audio/Video ports of the TV, and I didn't get any noises. If you meant for me to use the A520 Modulator, I haven't got the right cable for the RF OUT, I'm only able to use the A/V ports.

I'm still intrigued by the rattling noise though.

[circlip]

Hi DrDekker again.

The led colours on the keyboard are: power=orange, floppy=greenish

The Caps Lock light doesn't have any sequence as such, either I switch it on and it's steady, or I switch it on and it just flashes continually. Want me to crack it open again? (this is gettin fun. :-) )

[circlip]

Yes, meega, it's a green-screen. But I have plugged it into the tv once or twice. Startup screen "white with blue floppy with words "Workbench 1.3"", so I'm assuming it's a kickstart 1.3 if I'm correct.

EDIT: Does anyone think a motherboard replacement will (hopefully) fix my problems? I found a cheap one which I could buy next week. It has no chips.. so if a chip is the problem, I might make no headway.

[circlip]

Hi meega,

Well, I don't have workbench yet...

(that was a floppy I simply tried to boot unsuccesfully with, after reading further into transferring files to an Amiga (I'm getting workbench 1.3 hopefully next week))

But basically it asks for WorkBench 1.3... white screen, blue coloured disk icon. There is no "Plus" badge anywhere.

EDIT: If anyone wants screenshots of anything for further investigating (inside or outside of the A500) I can make them asap.

[circlip]

I do have a multimeter, I can give it a shot. I saw an Amiga 500 on ebay for about 50 bucks (excluding postage) and I don't want to fork out that much if I can avoid it.

EDIT: Ok, I have the pinout diag, here on the bottom of the PSU.


------\    /------
* +12V \  / * SIGNAL GROUND
        \/       |
         * -12V  |

* SHIELD GROUND *| -5V
------------------

So where should I put each probe? I especially don't know how to test the 5V lines. Forgive me, I've only tested a few "simple" things with a multimeter, never an A500 PSU. :-?

[circlip]

Thanks meega, I was thinking of doing that actually. Also if my A500 does its reset thingy, will it ruin the disk?

@Tomas and anyone, check my edited post above with the pins. The diagram really didn't turn out, but you get the idea.

[circlip]

@meega... hmmm... what to do with my cats? :crazy: We don't have A/C in our house, so fans are the buzz at our place, we have them in each room, gets pretty hot this time of year. I remember using one of them for my old C64 PSU, i think they all(??) have overheating problems, well my two C64 PSU's did anyways.

Man, Amiga disk drives are funny aren't they? They should've put a seperate LED for "write floppy" so we know when to be careful around it. :roll:

Edit: euch! spiders, little baby {bleep}roaches... kitty cats, at least we have no snakes in the city! :-)

[circlip]

Hi all... sorry @ orange for nick mix up. I just saw "Defender of Faith" and automatically took it for your nick for some odd reason.

Anyways, I'm going to crack open the A500 unit again, and see what the go is.

I'll try the "no keyboard" trick too, and PSU after 1/2 hour of off time. Only problem is that sometimes it won't play up as it should (like last time) so I'll have to check back a few times to see if everything definately is ok. I'll try gently pushing a few chips again too.

Ebay is one of my sources for stuff too TjLaZer, I saw an A520 modulator, new in the box and plastic wrapping! :-o

[circlip]

@ rkauer

It is written on the mobo this:

B52 / ROCK LOBSTER
GRR/I3P/GUAY/FISH
RVW/VFA/DCA
HJM/CJW/TC/SMK
GET/LLK

A500 REV 5

btw, what is a keyboard header? Is it the plug? (sbsolute newbie here.)