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NFG Forums => SIG X68000 => Topic started by: Martymcfly on December 24, 2012, 03:40:34 PM

Title: Power problems
Post by: Martymcfly on December 24, 2012, 03:40:34 PM
Disaster struck, and my X68000 fell over.  It was on standby mode when this happened.  When I sat it back up, it automatically turned itself on, but the standby button wouldnt work.  I opened up the case, and several of the shoddy solder joints done with the power supply had broken off.  I soldered it back together according to this schematic http://nfggames.com/nfg/x68repair/ (http://nfggames.com/nfg/x68repair/)  but now all I get when I plug the system in is the red standby light, and it won't turn on.  This is what it looks like now  (http://farm9.staticflickr.com/8222/8302041553_d7ed64f140_h.jpg).  Any ideas?
Title: Re: Power problems
Post by: lydux on December 24, 2012, 08:28:02 PM
Ouch...

NEVER power on a machine with such a mod without isolating soldering points !

You've got a big short circuit between the persistent 5v (purple wire) and the ground. Your resistor have way too long legs, it touch a metal plate on the floppy drive which is a ground !

Isolate all things you can here ! ALL metal part around are tied to the ground !
Title: Re: Power problems
Post by: caius on December 25, 2012, 12:44:48 AM
Or better, put the 74LS04 and the 4.7Kohm resistor on a perfboard.

P.S.

I wish a Merry Christmas and Happy New Year to all guys in this forum, especially to Eidis and Lydux!
Title: Re: Power problems
Post by: Martymcfly on December 25, 2012, 05:25:09 AM
Quote from: lydux on December 24, 2012, 08:28:02 PM
You've got a big short circuit between the persistent 5v (purple wire) and the ground. Your resistor have way too long legs, it touch a metal plate on the floppy drive which is a ground !

Isolate all things you can here ! ALL metal part around are tied to the ground !

It was definitely a subpar quick-fix job originally, and I'll probably redo the fix with a more permanent job if I can get it working again.  But where is the short circuit?  Although the resistor's legs are long, they are not in contact with anything else.  Do you see it wired incorrectly?

Thanks!
Title: Re: Power problems
Post by: lydux on December 25, 2012, 10:12:35 AM
I might be wrong, but from this point of view, the short is here :

(http://i.imgur.com/WHm8p.jpg)

The metal plate is tied to ground.
Title: Re: Power problems
Post by: Martymcfly on December 28, 2012, 12:15:44 AM
It does look like the resistor is contacting the plate, but there actually is no contact. Any other ideas? I think i might redo the job and open up the case to make sure the board doesnt have anything fried on it.
Title: Re: Power problems
Post by: eidis on December 28, 2012, 04:55:08 AM
 Hi Martymcfly !

Maybe this will help. You have the opposite problem, but they are closely connected.
http://gamesx.com/wiki/doku.php?id=x68000:soft_power_switch_troubleshooting_and_repair (http://gamesx.com/wiki/doku.php?id=x68000:soft_power_switch_troubleshooting_and_repair)

Eidis
Title: Re: Power problems
Post by: Martymcfly on December 29, 2012, 06:32:46 AM
Well I took apart the case and inspected all the boards (but didn't see anything suspect), put everything back together, re-soldered the power supply circuit, and now it works fine!  Thanks for the help guys.