Monitor will not power on (Hong Eun chasis, Samsung Tube) [PICS]

[tokyogameaction]

Hey Everyone!

I just purchased a Korean Percussion Freaks machine that needed a considerable amount of work. While I have gotten almost everything working, I can not get the monitor to power on. The tube says Samsung and the Chasis says Hong Eun. No caps appear to be blown on the chasis or neckboard. Both the fuses appear to be solid as well. I am running 120v directly to the monitor chasis from the wall. I was originally going to use a Isolation transformer but I can not find one locally ANYWHERE. I called Betson and East Coast Amusement and they both said they didn't think this monitor would require an Isolation Transformer.

I was under the assumption that the monitor should boot regardless of an Isolation Transformer, it would just run the risk of having a hot-chasis. I have run a multimeter all over the Chasis and am able to get 120 in several key places around the fuses. There is no high pitched power-on noise and no glow around the neck though. Any suggestions?

Thanks for any advice in advance =D

[MonMotha]

No SMPS to be seen on that chassis, so it likely needs an iso xfmr.

You can run a beast like that without one if you disconnect EVERYTHING from it and ensure that the frame is electrically isolated.  It will have a hot chassis, then, so don't touch it.  If you attempt to run it with anything connected, you may end up with a destructive ground loop.  Running a monitor like this without an isolation transformer is asking for trouble no matter how you spin it, so don't do it.

Korean Bemani cabinets are notoriously poorly grounded (usually lacking any form of earth grounding), so there's another safety hazard to be aware of.  Japanese Bemani cabinets tend to float everything on the DC power side, so you could theoretically get by without an iso on the monitor (but then all your wiring and sensors would be hot, which is bad), but don't rely on that.

These Korean cabinets often use Ducksan monitors, but I don't recognize this particular unit.  Newish Korean PF I've futzed around in had a different monitor.

Have you checked the fuses with a meter?  A visual inspection is not 100% reliable.

Someone else may have better ideas, but check for an open somewhere in the horizontal deflection area (bad joint, burned/bum trace, open HOT, etc.).  That would cause what you're seeing.  If you can find a B+ testpoint or something, check that it's something reasonable (100-150VDC), but don't attempt to adjust without IDing the monitor.

[Ken Layton]

Judging by the picture, this monitor definitely needs an isolation transformer.

Never rely on just "looks" of a capacitor. Get out the capacitor ESR meter and check 'em out.

[tokyogameaction]

Unfortunatally since I have limited to no knowledge of arcade monitors I have no idea what an capacitor esr meter is? I understand the unit needs an isolation transformer, but before I order one online (since noone sells them locally I want to ateast see the unit turn on and working first.

[MonMotha]

I would not recommend running this without an isolation transformer.  It's very easy to get in trouble without realizing it.  Injury/death or destruction could result.

If you don't know what a cap ESR meter is, then you almost certainly don't have one.  It's not a function on a standard multimeter, unfortunately.  There's only ~17 electrolytic caps on there; you could just replace them all.  I'm not normally a fan of the "shotgun all caps" style repair, but this is a pretty simple monitor.  Given the simplicity, it's likely repairable no matter what's wrong as long as the tube and flyback are OK.

If you have any other cabinets, one of them likely has an isolation transformer in it you could borrow.  If not, look up your local Kirby Risk or Grainger.  You'll pay some money, but they should have one, and you won't have to pay to ship the darned thing.  Once you've got it running off an isolation transformer, you can troubleshoot further.  Many other monitors you'll find as replacements (if you go that route) will require an isolation transformer, too, and they're just plain handy to have around, so no harm buying one.

If you can, try to locate a model number somewhere.  That may assist in locating a schematic or service manual.