Well I got my free cocktail that I mentioned in another post...  I've got a few pics here:
http://www.mikesgamesroom.com/cocktail

I don't know much about these things but I'll look into it this weekend...  At first glance it looks like the isolation transformer is toast although it could be a power cord issue..

Can someone who knows about this stuff tell me:  Is it normal for the monitor to blow a fuse when connected without an isolation transformer???  I thought the transformer was only to prevent the whole chassis from being "live"...

Mike

Well, in case you didnt know, it looks like a (phase 2?) Midway cabinet that was used for Galaga and Ms Pacman.

As far as the fuse blowing? Using a monitor without an isolation transformer will not blow the fuse.  Not safe to do, but will not blow a fuse either.

It blows without an isolation transformer, but not when it has it?  Sounds like a short.

The original issue was a power cord problem..  The isolation transformer is good.  The monitor fuse keeps blowing tho.  Also, I only have partial sound in the game.  I only get the white noise (drum sounds, etc) and no FM music..  Obvisouly the first thing I want to fix is the monitor...  Where do I start??  Is there an online info place like Marvin's but for video games??

Mike

Also... Any idea where I could get a glass and the clips that hold it on??

Mike

What is make/model is the monitor?  I have some documentation for certain monitors that might help in troubleshooting.  

You could also ask over at cgcc... they are most videogame/arcade guys there and know who to fix things ... well some do.

As for clips, the usual (arcade) sources should have them such as:

http://www.arcadeshop.com
http://www.mantisamusements.com
http://www.quarterarcade.com

PS.  I just looked at the photos... looks kinda like a Wells Gardner...... take a look for markings on the circuit board...ignore the tube (unless you see G07 or WG on it)

http://www.therealbobroberts.com has a great monitor identification page (and I think you can buy clips too).

Also, do a google search for Randy Fromm... he is/was the Clay equal for videogames but he now just overcharges for his videotape lessons (which are very useful, if pricey).

If you're blowing the main line fuse on the monitor at power-up I would start with the horizontal output transistor or the B+ voltage regulator (Start with the H-O transistor first).  Depending on the make and model these could be anywhere, and I'd hop over to Randy Fromm's technical site for very good troubleshooting workflow diagrams (by monitor type).

Let me know if you've got any other questions.

Doug

I can't seem to find those flowcharts..

How do I check that transistor in circuit??  What DMM values am I looking for?

Would a blown flyback do this??  I found a common repair kit for my monitor which includes a cap kit, a flyback, and a voltage reg.

Mike

Here's the weblnik directly to the page with all the best monitor tech info.  The workflows are towards the bottom.

http://slot-tech-ftp.serveftp.com:8080/technical_department/

As for testing the HO transistor in circuit, not sure if you can test this in circuit but whatever is blowing the fuse on power up is definately shorted out.  You should be able to "ring out" the short in a transistor as long as you know what leads to test.  When it comes to what leads it all depends on the type of chasis, and even then you might have to look up the datasheet for that part first.  I think the rule of thumb is .5 - .7 in the diode setting for a good reading (don't quote me on this though), but you're looking for a dead short so it'll be easier to use the beep setting on the DMM (find a "beep" from the meter where you shouldn't, right?).

Did you figure out what Mfg and model monitor you're working on yet?

Doug

Ooops thought I had mentioned it already but it's a WG K7000 series (K7951).  Found the site and chart just before reading your response.  Found the problem too..  Diodes D20 and D21 shorted out..  about this problem the chart says: VERY RARE BUT OCCURS WHEN TRYING TO RUN MONITOR WITHOUT ISOLATION TRANSFORMER..  D'OH!  Guess what Mike did yesterday while troubleshooting...  

Rest tested and seems fine..  Now I have to find some 1A 600V Diodes..  and of course another fuse

Thanks for the help.  I'll let you know if it was indeed the problem.

Mike

I know the K7000 parts list doesn't give the generic part# for this diode, but I think its just a standard 1N4005.  So anything from 4005 to 4007 will do the job just fine.  Whats the part# listed on the actual diode? (just in case)

Doug

Actually, according to my NTE catalog, anything from 4001-4009 will do.  I put in some 4004.  That corrected the problem.  Monitor works, however, there's a bit of distortion at the top of the screen..    I'll try some adjustments but it probably needs a cap kit.

Now if I was REALLY keen I'd try to fix the sound issue..  Just having "drums" and bass is kinda weird..

I think I have a MAME candidate.. or maybe turn it into a Ms Pac Man or Galaga since it's the same cab.

Mike

Bending at the top of the screen is almost a sure sign that the capacitors need changing.

Actually, the solution was MUUUUCH simpler...  H.HOLD was out of adjustment.  It's perfect now.  Thanks for the suggestion tho.

Mike

So what game is it ? Screenshots ?  

It's called Wise Guy (or Yam! Yam!).  It's a puzzle type game where you have to figure out the path required for the little bear to push the diamonds in the chutes.  The kids like it but I'll turn it into something else as soon as I get a glass..

Just for you Azatotht I have screenshots here:
http://www.mikesgamesroom.com/cocktail

Mike

Thx Mike !

Sweet, good job on this ! Monitor seems clear, sounds like you got a good deal on it

I am starting to like cocktails   Battlezoneman Warlords was way cool !! 4 players game is awsome. Also his Tron cocktail is pretty nice  

Well my fun was short lived..      

I've got a short again and it's blowing fuses..  There's a few other things to look at on the board but that'll be for next weekend..

Mike

Here is a question... have the parts you have replaced failed again?  Just wondering if it is something higher up in the chain?

Hey Mike, just so you know your NTE guide might have a mis-print if it states you can use a 1N4004 in place of a 1N4005 (600V part) or higher.  The 1N4004's might work in place of the 600V parts for a little bit, but I'll bet they break down fairly quickly.  This may be the reason your monitor has started blowing fuses again.

Now seeing as I work for an electronics distributor I took the liberty of checking one of our suppliers websites for specs on the 4000 series diodes for you.  The 1N4004 only has a VRM rating of 400V which is why I mentioned in my earlier post that you'd need a 1N4005 or higher part# to work correctly.  (This is why we as a disti only stock 4004's and 4007's, and I would try to explain why we don't just stock the 1N4007 but it's really boring technical stuff that's just no fun to read about)
Here's the link to the PDF just in case anyone wants to confirm this.....

http://www.centralsemi.com/leadedpdf/1N4001.PDF

I'd start with replacing the two 1N4004 diodes with higher voltage ones first and go from there.

Doug

OK I'll check that.  As it turns out although the schematics call for a 1A diode, in reality the board had 3A 600V diodes installed (1N50XX - can't remember right now)..  Go figure..

Mike

That's fairly common, as we have seen many misprints in our pinball schematics/BOM's too.  Are the other 2 diodes in the rectifier circuit the same?  (3A/600V)  If so I'd replace the two bad ones you've got with the same ones, otherwise try using what the manual states as they may be just fine.  

Let me know if you have any difficulty trying to locate the 1N5406's locally (that's the correct part# for a 3A/600V rectifier diode), and I'll try and dig a few up as samples and send them out to you.

Doug

I have a few of those midway cabinets. from the pictures, it looks like the metal clamps that secure the top to the bottom of the cab are missing (there are 2). this is what prevents someone from tilting the machine open, i am not referring to the clips for the topglass. just be careful, as the power source to the monitor is right inside the coin door. especially with kids playing with it, i would be carefule and make sure it can be locked up securely. harry

The 2 clips are there.  Actually right now anyone can remove the bezel and stick there hand around the monitor and get zapped..  That's why I need a glas ASAP.  Seems like I've found one..

Mike

Fixed the missing sound issue..  Didn't think it could ever be that easy..  Bad solder joint on 1 cap.  Sounds now works 100%..  

Now if I can only get the monitor up and running again!  

Mike