ledfrog
Active member
Sharp Image SI-727R-DS no power, no neck glow, no image, faint ticking sound
I recently acquired a Neo-Geo clone cabinet from an auction and the monitor does not work. When powered up, I hear a faint ticking sound as if it's trying to power on, but then doesn't. There's no neck glow, no typical buzzing, no screen static, nothing....
I've been working off of Ken Layton's awesome repair sheet: http://www.arcade-museum.com/manuals-monitors/Sharp Image SI727RDS Monitor Repair Guide.pdf along with some general monitor repair guides all over the internet, but I'm at a loss on this.
Sorry this is so long, but I wanted to minimize a lot of back and forth by giving as much info upfront as possible!
Here's what I've done so far:
Until recently, I had not powered the chassis up without putting it back in the monitor, but I got tired of taking it out and putting it back in over and over. I don't have a proper bench set up for this as I don't usually do these kinds of projects, but I thought with my basic skills, I'd give this one a shot.
Anyway, I finally powered it up while removed from the monitor so I could hear the faint ticking sound much better. I ended up tracing the sound to a part that I'm not familiar with. I've seen it in other electronic devices, but I have no idea what it's called. (See second attached pic)...it's the black thing that's holding some copper windings. If you look at the third picture I attached, you'll see where it goes on the board. It jumps J803 and J802. From what I can tell, it's the last stop before the 120v AC enters into the board. If you're not familiar with this chassis, the two solder points just below the C801 marking are the AC wires (white on the left and black on the right which heads over to the fuse).
I removed it from the board to make sure I was right and sure enough...once removed, the ticking stopped. Of course the board has no power, but it didn't seem to have power before so here are my questions:
Just an FYI, when I test components after the ticking piece, I can still read 120v so I assume it's working, but I don't know what else it could be in that area. Interestingly, when the 120v hits the bridge rectifier, it drops down to about 72v. I don't know if that's normal...
ANY help would be greatly appreciated!!!
I recently acquired a Neo-Geo clone cabinet from an auction and the monitor does not work. When powered up, I hear a faint ticking sound as if it's trying to power on, but then doesn't. There's no neck glow, no typical buzzing, no screen static, nothing....
I've been working off of Ken Layton's awesome repair sheet: http://www.arcade-museum.com/manuals-monitors/Sharp Image SI727RDS Monitor Repair Guide.pdf along with some general monitor repair guides all over the internet, but I'm at a loss on this.
Sorry this is so long, but I wanted to minimize a lot of back and forth by giving as much info upfront as possible!
Here's what I've done so far:
- New flyback
- Full cap kit (mainly because there were some caps that looked like they were starting to leak)
- Replaced the vertical output chip (it was fried out of pin 3 - see attached pic)
- Checked for obvious board damage and found none
- Reflowed many solder joints just in case they were cold (didn't find any obvious ones)
- Used my meter to check for bad traces and haven't seemed to find one yet
Until recently, I had not powered the chassis up without putting it back in the monitor, but I got tired of taking it out and putting it back in over and over. I don't have a proper bench set up for this as I don't usually do these kinds of projects, but I thought with my basic skills, I'd give this one a shot.
Anyway, I finally powered it up while removed from the monitor so I could hear the faint ticking sound much better. I ended up tracing the sound to a part that I'm not familiar with. I've seen it in other electronic devices, but I have no idea what it's called. (See second attached pic)...it's the black thing that's holding some copper windings. If you look at the third picture I attached, you'll see where it goes on the board. It jumps J803 and J802. From what I can tell, it's the last stop before the 120v AC enters into the board. If you're not familiar with this chassis, the two solder points just below the C801 marking are the AC wires (white on the left and black on the right which heads over to the fuse).
I removed it from the board to make sure I was right and sure enough...once removed, the ticking stopped. Of course the board has no power, but it didn't seem to have power before so here are my questions:
- What is this piece I'm holding and what exactly does it do?
- Why does it make a ticking sound and does it have to do with my monitor not powering up?
- If I simply soldered two basic jumper wires to emulate the missing piece, will it cause damage to the board or any components? In other words, can I do without it?
Just an FYI, when I test components after the ticking piece, I can still read 120v so I assume it's working, but I don't know what else it could be in that area. Interestingly, when the 120v hits the bridge rectifier, it drops down to about 72v. I don't know if that's normal...
ANY help would be greatly appreciated!!!