Hey guys!
I have a sharp 68k with a bit of a problem. When i got it it looked like it was in really good shape and in the box.
However i noticed that the psu caps were bad so i changed them it's fairly common on these machines so it was no trouble.
I boot it up everything looked fine until i noticed a lot of residue on the computer i look everywhere and noticed a lot of caps have leaked.
So i buy a kit for the machine and start working on it.
However i stopped in the middle of it because i needed to do something else.
I checked if it was still booting up. It was.
Here is the problem now it just won't boot now it gets stuck in a loop in the first step of booting up so there is no image and tghe powerbutton does nothing.
Upon first plug in the led indicator should go green then red then you push the button and it boots up for real.
Mine gets stuck on the first phase green and never goes red or displays anything.
Here are the step i took for now:
- checked i didn't lift a trace.
- checked all the continuity between the caps and the rest.
- checked i didn't have the wrong polarity.
- checked i didn't have the wrong values.
- checked the voltage
Everything is fine but the computer still won't boot.
Anyways sorry for the bad english and the long post.
I just don't get it.
Any helps would be really appreciated!
Cheers!
Sharp X68000 Troubleshooting
Re: Sharp X68000 Troubleshooting
X68000 problems can roughly be categorized into two different types.
First type is problems related to the power supply and soft power circuits. There are components on the power supply and some on the bottom board that might be involved in this.
These types of problems are usually diagnosed by circumventing the soft power on circuit and feed the necessary voltages to the right voltage input pins on the bottom and motherboard. If memory serves me the required ones are 5V and 12V.
The second type of problem has to do with failure of components on the bottom and motherboard. Those are often impossible to diagnose and/or fix unless you are a very experienced electronic engineer.
I suggest you try to bypass your machines power supply by feeding 5/12 volts directly to the machine from an outside source and see if your machine boots. If it does something related to the power on circuit broke. Most likely culprits are some resistors and diodes. There is information on which are most likely to break on the nfg forums somewhere. Try to do a search.
First type is problems related to the power supply and soft power circuits. There are components on the power supply and some on the bottom board that might be involved in this.
These types of problems are usually diagnosed by circumventing the soft power on circuit and feed the necessary voltages to the right voltage input pins on the bottom and motherboard. If memory serves me the required ones are 5V and 12V.
The second type of problem has to do with failure of components on the bottom and motherboard. Those are often impossible to diagnose and/or fix unless you are a very experienced electronic engineer.
I suggest you try to bypass your machines power supply by feeding 5/12 volts directly to the machine from an outside source and see if your machine boots. If it does something related to the power on circuit broke. Most likely culprits are some resistors and diodes. There is information on which are most likely to break on the nfg forums somewhere. Try to do a search.