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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: curtis on December 23, 2013, 02:55:48 AM
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Okay, I'm beginning to think I'm snake bit.
I got the CD-ROM in to install in my A2000. Checks out okay. Yay!
So, I'm putting everything back together employing cable management and wiring routing to keep things nice and neat.
Power up afterwards and suddenly the mouse is stuck in the upper left hand corner and only the right mouse button works! HUH?!?!?!?!
So start stripping things down to make sure there's not a conflict anywhere.
Thylacine board, out!
GVP 030 combo board out!
Down to motherboard and nothing else.
Pop in a boot floppy and turn on the power. Nothing! NADA!!!!
Check the cpu and it's just sort of sitting there not making very good condition. Suddenly remember using the larger pins from the expansions I'd plugged in there and realize some pins are probably not making contact. Fortunately I have some spare sockets with the larger pins. Install those and power up.
Computer boots up. Yay.
However, the mouse is still stuck in the upper left corner and only the right button is working.
Fire up the PC and web search for probable causes. Hmmm, says check the odd CIA chip.
Okay, I've got several known good spares. Swap BOTH out (just in case...). Check contacts and legs for any bent or possible bad connections. Looks good.
Power up. SAME THING!!!
Mouse? Swap mouse with known good. No change.
Looking for suggestions, please!
Curtis
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have you checked the voltage on mouse port?
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I think @orange is onto something here. Check the voltages if you have a schematic. Also, it may sound dumb, but try moving the mouse pointer with the keyboard shortcuts. Just to make sure it *does* move. Also I'd remove the drive sled and inspect carefully the area around the back of the mouse port. Check for any battery leakage that might've snuck its way over there, loose solder joints, etc. You may need to remove the motherboard and check from the bottom, as well. Try booting from a game disk and make sure your joystick/port 2 works okay.
A few other similar tips here:
https://groups.google.com/forum/#!topic/alt.amiga/GLNKqm0ey5M
Good luck!
As a side thought, what revision motherboard are you using? If it turns out to be a motherboard problem and you're using a 4.x, you might be better served to just replace it with a 6.x. Much fewer bugs in those revisions. ;)
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It's been a while since I had an A2000 but it has a keyboard lock right? I think for mouse and keyboard. Maybe it got loose from the main board. Check the to see if the cable is plugged in.
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Newer A2000 mobos had a fuse for the mouseport.
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@ Orange, will check voltages when I get home. Oh wait, "She Who Must Be Obeyed" has decreed we're going to to dinner tonight. Guess I'll check it out when we get home...
@ Mike, I've had it down to just the mbo, what the heck, pull the motherboard out also!
@Nitro, no, the 2000 doesn't have a keyboard/mouse lockout.
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Found the schematics for the mouse port and checked voltage. 5V line dead!
Next, find schematics to chase down the 5V line.
Oh drat!!! There's a fuse in the line. Fire up the computer, check one side of the fuse, nada! Check the other side, 5V!
Grab a jumper wire with clips on the ends and bypass around the fuse. Turn on, again. Mouse moves perfectly!!!!
So, I'm thinking of just soldering a small, single strand of wire around the fuse, unless someone happens to know the value of the fuse link AND if they're readily available at Radio Shack.
Comments?
Curtis
Curtis
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That fuse saved your a** one time, I'd try to replace it with another one. Is there no markings on or near the fuse to indicate it's value? Great job troubleshooting!
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Mike, good point. I have been noticing every time I touch a piece of metal near my workbench, the screen flickers! Guess I'm building up quite a bit of a charge just walking around barefooted!
There's not a single mark on the stupid thing. Just a green resistor looking critter.
Guess I'll dig through the internet and try to find the value.
As far as troubleshooting, I have to lay a lot of the credit on the people here who responded. Sure makes things a lot easier when you have resources who have been there, done that around. I just follow suggestions and go from there.
That fuse saved your a** one time, I'd try to replace it with another one. Is there no markings on or near the fuse to indicate it's value? Great job troubleshooting!
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More info for those who are interested and may have to revisit this one day...
The fuse is a 4 amp pico fuse by Little Fuse. Not sure on the series, but it's approximately 1/4" in size, approximately the siae of a 1/8W resistor.
Now to find a source. Obviously, Radio Shack won't have it...
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More info for those who are interested and may have to revisit this one day...
The fuse is a 4 amp pico fuse by Little Fuse. Not sure on the series, but it's approximately 1/4" in size, approximately the siae of a 1/8W resistor.
Now to find a source. Obviously, Radio Shack won't have it...
Don't count them out, they may have something serviceable or be able to get one.
And, as always, check eBay.
US source, about $5 for 5.
http://www.ebay.com/itm/5PCS-PICO-FUSE-FIT-LITTLE-FUSE-4A-4-AMP-fit-HP-LG-SAMSUNG-/321276151539?pt=US_TV_Boards_Parts_Components&hash=item4acd8d06f3
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Well, I think I have it identifies, at Digikey I picked part number F3173CT-ND.
Heck, looking at the specs, there were several basically the same, so I took a stab and picked one with the right sizing and ampere rating. On a 5 volt line, I really don't think there's much difference between a 125V and a 250V fuse!
Went ahead and ordered 10 to get the 4 cent price break AND to have a couple of spares, just in case...
So, should arrive in a few days. Will replace then.
Also,if anyone else has this problem, you now have a couple of sources for fuses, either Digikey or you can give me a yell!
Now to somewhat reassemble this beast while I wait for the fuses to come in and start working on the next project.
I hope people who have been following this thread picked up some useful info and tips so you don't have to pull your hair out like I've done...
Curtis
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Good Stuff ;)
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told ya! ;-)
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Well, I think I have it identifies, at Digikey I picked part number F3173CT-ND.
Heck, looking at the specs, there were several basically the same, so I took a stab and picked one with the right sizing and ampere rating. On a 5 volt line, I really don't think there's much difference between a 125V and a 250V fuse!
Went ahead and ordered 10 to get the 4 cent price break AND to have a couple of spares, just in case...
So, should arrive in a few days. Will replace then.
Also,if anyone else has this problem, you now have a couple of sources for fuses, either Digikey or you can give me a yell!
Now to somewhat reassemble this beast while I wait for the fuses to come in and start working on the next project.
I hope people who have been following this thread picked up some useful info and tips so you don't have to pull your hair out like I've done...
Curtis
The voltage rating only indicates the insulation rating, your voltage is not that high. One amp is one amp no matter the voltage. Easiest way to check a fuse is with same voltage setting and measure across the fuse.
Open will give you full voltage, good will be zero.
Chri
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Kind of figured that's what the voltage rating was. Since the line is a 5V line, I'm pretty sure I'm okay with 125V rating! :)
Got the fuses in yesterday. Box really had me confused as to what it was until I opened it.
These things are TINY! About the size of a 1.8 watt resistor. The box was 8"X8"X1"! Yeah! There was more packing material than merchandise! Heck, they could've just used a couple of pieces of light cardboard (like a cereal box) and shipped it in a plain envelope.
Anyway, will replace the fuse tomorrow and go from there. Will probably just clip the leads on the old one and make a small curl on each end of the new one and solder it in like that. Clip the excess lead and done.
Curtis