Sanyo 20 EZV blowing fuse

[ncflagg]

Hello.

     I have a Sanyo 20-ez or (20 ezv or whatever) that is not powering up.
When I turn it on it blows thw 300mAh fuse every time. Everything else in
the cabinet works fine. I also have another identical cabinet (Nintendo VS.
Unisystem) that is fully functional.

     Does anyone have any suggestions on where to start?

[Kevin Mullins]

What kind of electronics level do you have?

Is the flyback all bubbled up looking around the top?
is the Horizontal Output Transistor shorted?
Has it had a cap kit put in recently?

[ncflagg]

I have a little electronics exp (have a multimeter and can test voltage, continuity). I can solder parts.

If the flyback is the brown water tower looking thing there is a luttle crusty residue on the top but no melted plastic as far as I can tell.

Not sure where the H Output Transistor is.

I bought a cap kit at first thinking it might help and decided at some point that it wouldn't so I haven't put it in yet.

The monitor has not yet worked in my posession.

[ncflagg]

Is there a test I can run on the flyback transformer?

[ncflagg]

Anyone have any ideas?

[grantspain]

what part of the circuit does the 300ma fuse protect?

[ttontis]

Here is a link to the Schematic http://www.eserviceinfo.com/downloadsm/8948/Nintendo_20-EZV.html I would start with Q901 and IC601. Here is the NTE data sheet on the Q901 alternate. http://www.nteinc.com/specs/2300to2399/pdf/nte2307.pdf IC601 is a discontinued part and I tried to check some data sheet websites and all I could find was a description with no technical data. http://www.tranzistoare.ro/datasheets2/40/40839_1.pdf. That's where I would start.

Ted

[ncflagg]

Hello

     Can anyone identify this monitor for me. It's in a Kid Niki (It may have been a converted Mario Bros). I may need to order a cap kit for it or if it is what I think it it (Sanyo 20) I may get one of the two I have up and running.


Thanks

[SirPeale]

Yeah, that's a Sanyo.

[ncflagg]

I hooked up this Kid Niki with the Sanyo 20EZV and replaced a 300mah fuse on the monitor. As soon as I turn it on (just like the other Sanyo 20EZV  I have) it blows the fuse.

[ncflagg]

I installed a replacement flyback from ArcadeShop Amusements and was so sure it was going to work. Why? -fuse blows out-

Installed cap kit that had been sitting there for a couple months. -fuse blows out- 

I replaced a small circuit board and small tranformer on the left side of the unit with a known working set from another monitor. -fuse blows out- 

It is apparent to me now that the problem lies in the main circuit board (or I guess possible the neck board). I have two monitors with the same problem. The 300mAh 125V fuse blows out as soon as it gets power. The tube never gets a chance to charge up.

Can anyone point me in the right direction?

[Kevin Mullins]

Check Q901 which is the voltage regulator.
Could also possibly be the HOT that is shorted.

[ncflagg]

Thanks, Kevin. I'll check it out.

[ncflagg]

For q901 I got .6-.8 readings in diode mode. For q902 (if the q902 is the HOT and q902 is the button-shaped thing mounted on a plate next to the flyback) i got all 0's all directions for the diode check and .3 KOhm resistence C-E.

[Kevin Mullins]

(if the q902 is the HOT and q902 is the button-shaped thing mounted on a plate next to the flyback) i got all 0's all directions for the diode check and .3 KOhm resistence C-E.

Yes, that's the HOT. (Q902)
And yes, that's bad.

Does it show a short from both legs to the metal "case"? 
( all 0's either direction in diode mode )

Pull that transistor out of circuit, then try a new fuse if you have one handy.
I'd almost bet it doesn't blow.
(ok, I wouldn't really bet) 

[Neilyboy]

im sure you are way ahead of me here but consider this a bump i guess hehe but your not just plugging it into 120 power are ya? I think this monitor requires 100v. anyway free bump for you.

Neil

[ncflagg]

Yes it does show 0 from the legs to the case. I removed the q902 hot and the fuse did not blow. I replaced the D993A (2C) with a D869 (4e) from another Sanyo monitor.

It powers up! (Thanks a million Kevin!)

I ran the same diode checks on it as the other and found only one difference. From one of the legs to the metal case read .4 but everything else read 0's again.

The screen was a little wavy in the Kid Nikki machine it was in but not with Excitebike. However, a little of the picture is cut off at the top (vertical size pot had no effect). Suggestions for that?

Will the 2SD870 H.O.T. from Arcade Amusements or Mike's Arcade work as a replacement?

[ncflagg]

Got the wrong transistors delivered and still waiting on those (I hope they are the right ones). On my other Sanyo 20 ezv monitor that was blowing it's 300mah fuse I removed the HOT q902 and the fuse still blew. I decided to take the old flyback from the other monitor and put it in this one. The fuse did not blow. After a HOT transplant the monitor powered up! I noticed when I had both older flybacks out at the same time that while they both looked identical at first, one was a crustier looking on the top and they appeared to be slightly different models. I wonder if the one that is working was a newer design.

This monitor is having the same problem as the other did when I got it running. The top part of the screen is slightly cut off. Since the only commonality was the HOT I've been swapping around I'm hoping I've found the cause of that problem also.

[ncflagg]

I got the 2SD870 H.O.T. from Mike's Arcade and it works beautifully. Thanks for everyone's input.

[Kevin Mullins]