Dig Dug Cocktail G07-FBO 13" Needs Help

wxforecaster

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I've separated this out from my Dig Dug repair thread since this aspect of my troubleshooting isn't game specific at this point.

What we know so far:
1.) Despite PCB problems, the monitor appeared dead with no neck glow.
2.) I tested the B+ and got a whopping 166V, which explains item one (X-ray shut down).

I have removed and cleaned the chassis/neckboard. NOTE this is the 13" FBO version, and I'm having a lot of trouble finding documentation or past repair logs on it. Here's what I've noted:
1.) Flyback inspects good
2.) I tested the HOT putting a multimeter in diode mode and putting the black lead on the tab closest to the flyback and the red on the other one. I measured 0.000V which I perceived as dead. Is this the proper way to test these on the FBO?
3.) I tested the voltage regulator by putting a multimeter in diode mode and putting the black lead on the tab at the back of the chassis and red at the closest. I got a value of 0.63V. Again, what is the proper way to test this.
4.) Both F901 and F902 are surface mounted, but visually inspected and continuity tested as good.
5.) I've tested most of the resistors and they all are good. I did notice that R314 (back left corner) is a 4.7k ohm instead of the 390 ohm.

Any help on where/how to proceed with testing (especially 3/4 above) would be greatly appreciated. Right now I have a HOT, flyback and cap kit enroute. The FBO version is strange because a number of components from the CBO aren't even present on the board.

Evan

digdug_chassis1.jpg


digdug_chassis2.jpg


digdug_chassis3.jpg


digdug_chassis4.jpg
 
How can I determine which are the base, emitter and collector pins of X04? I want to verify the wiring is correct and apparently the emitter also becomes the test point once I remove the collector from X701.

I have the white wire from R1 and a tan wire going to the "left" leg (if I'm looking toward the tube with R1 to my left), a black wire going to the center, and a red wire going to the right. Oddly enough the regulator on my G07 19" doesn't even have a center leg.

Can anyone verify this is correct and let me know which legs are E,C,B?

Evan
 
DUDE!

Stop IMMEDIATELY!

You have VITAL components missing from that chassis!

Now that I have seen pics of the chassis, you have big trouble in little china.


You WILL need an EXPERT to repair that chassis.
 
DUDE!

Stop IMMEDIATELY!

You have VITAL components missing from that chassis!

Now that I have seen pics of the chassis, you have big trouble in little china.

You WILL need an EXPERT to repair that chassis.

Dave, What's missing?...nothing's jumping out at me.
What is jumping out at me.....all those original caps!

Edward
 
Dave, What's missing?...nothing's jumping out at me.
What is jumping out at me.....all those original caps!

Edward


There's nothing missing here Dave, all those "missing" parts you see in the B+ section are normal for the FBO. I have one burning in on the rig right now with the same missing parts. Also, that black area you see on the 901 fuse may be nothing more than a check mark from a previous tech, my chassis has the exact same black mark on the fuse and i've seen this alot in various colors.
 
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Dave, What's missing?...nothing's jumping out at me.
What is jumping out at me.....all those original caps!

Edward

There's nothing missing here Dave, all those "missing" parts you see in the B+ section are normal for the FBO. I have one burning in on the rig right now with the same missing parts. Also, that black area you see on the 901 fuse may be nothing more than a check mark from a previous tech, my chassis has the exact same black mark on the fuse and i've seen this alot in various colors.

There I go talking while medicated again. Wife brought home this nasty chest cold and I can't even hold an iron right now.

Lot of original looking caps, but a very small few not original caps too. F901 sure looks burnt up, but pictures can lie.

You guys help this guy out, I am going to sit this one out until I feel better. That way I don't interject any more dumb shit into the equation.
 
I can tell you this much: do NOT replace the flyback. There is a difference between the 19" G07 fly and the 13". Modesitt should be along shortly to back me up on this.

Original caps, however...replace them all.

The repairs on this are pretty much the same as the 19" G07.

With a high B+ like that (btw, kudos for actually CHECKING and POSTING the b+) I'd be checking the voltage regulator and other things in the power supply circuit.
 
Those missing parts look correct to me, Dokert. In fact they soldered the through-holes closed underneath to prevent you from sticking stuff in them.

Also, on the FBO they "painted" F901 with a black stripe and F902 with a green stripe. Believe it or not, both are good.

A cap kit and HOT are already enroute from Bob, but the caps definitely don't necessary explain the insane B+. So, per the tech memo referenced above, I have disconnected the collector leg from X701 and going to slap the monitor/chassis into my ms pac cocktail here this morning and see what voltages I get at X04 (hence my question on which legs were which).

Evan
 
I can tell you this much: do NOT replace the flyback. There is a difference between the 19" G07 fly and the 13".

I'd always heard this, and I know the manual lists different part numbers for the flybacks.....and I'll admit, I've seen very few FBO's in my life. Several weeks ago I had two Electrohome 13" FBO's. One was working...the other was missing it's flyback....they both had original caps. I recapped both, and pulled the working flyback off the good chassis and installed it on the chassis without a flyback. It fired up fine. So...I assumed I was screwed. No one reproduces the FBO flyback, and I was one short from having a working chassis. I didn't have any new G07-CBO flybacks in stock at the time, but I had plenty of working pulls. I threw one of those on it and it fired up fine....B+ was good, and I let it burn-in. No issues. So, I've got a 13" working with a 19" flyback. Maybe the new reproduction flybacks are different?...maybe I'll throw one in and see what happens. I can shoot a picture if anyone cares.....

Edward
 
I have used reproduction 19 inch flybacks on 13 inch monitors without problems... at least for the G07 series. I asked Bob Roberts this very question when I was new in the hobby (since I knew they were different part numbers) and he told me the repros were acceptable for both chassis types.

Mongo's rule of thumb when dealing with G07's: Don't even bother troubleshooting them until AFTER you have installed a cap kit at the minimum. For the extra few bucks ($16 last time I checked) just replace the flyback as well. Now start troubleshooting.
 
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Yeh unfortunately, Bob is out of flybacks until around New Years he thinks.

However, some GOOD news. I hooked the monitor up to my known working Ms Pac Man.

With the collector of X701 desoldered,
I now DO get a raster picture (that quasi resembles the Ms Pac Man start screen albiet with jumbled/wavy screen). Surprisingly good colors!

The B+ measured at X04 is still too high at 145-148V.

This pretty much confirms a problem in the power regulator section.
Since I know X04 is good, the tech bulleting says to check X901, X902, D905 and C905. However, there is no X901, X902... not much to this section.

We'll make an arcade tech out of this pinhead yet!

Evan
 
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I was going to stay out of this until I feel better and can focus.

The replacement flys that Bob and Chad both sell WILL work fine for either the FBO or the CBO. I have personally verified this on both models using the exact same fly.

Unless you have replaced X04 you do not know that it is good. Regulators can fail in either direction. If you had a B+ of 166vdc and removed X701 and your picture sort of came up and now your B+ is 140-ish, suspect your X04 regulator to be BAD and replace it.
 
I actually asked Bob Roberts about the regulator as well before he shipped my kit, and he said he's only seen 1 go bad in the 17 years he's been working on countless monitors and pretty much everything else was fried on that one.

Getting .47V collector-base and .63V emitter-base, and open on the other 4 permutations would surely side with this the X04 being good. Those numbers are spot on.

Not ruling it out, but I'd say something else is amiss. Again, I was hoping someone had an FBO to confirm the wiring (looks unmodified).

Looking at the tube and turning left to look at X04:
I have the white thick wire from R1 joining up with a tan wire on the left leg of X04, which then runs to B1.
I have a black wire on the center leg of X04 which runs to E
I have a red wire on the right leg of X04 which runs to B2

Lastly there is an orange wire which runs from the mount (unioned with a bare wire running from the front leg of R1), which then goes to B3

Evan
 
I actually asked Bob Roberts about the regulator as well before he shipped my kit, and he said he's only seen 1 go bad in the 17 years he's been working on countless monitors and pretty much everything else was fried on that one.


One? Wow. I see bad VRs on G07s all the time.

Despite being different flybacks, the one for the 19" CAN work, but there have definitely been instances where one was installed, and the chassis had issues. Replacing it with the original flyback returned it to operating status.
 
Well, now I'm completely baffled. Wouldn't be the first time, definitely won't be the last.

Did the cap kit this afternoon and replaced the HOT. No troubles. Tested continuity. End of story. Made sure to solder back in the leg of X701 from the previous post. Triple checked the polarity on all the new caps.

Hooked up the G07-FBO to my known working Ms Pac Cocktail and nothing. Not smoke, no fumes, no blown caps, B+ of 0V, nada. Fuses still good. Big white still 220 ohms. HOT triple checked to make sure the insulation is good and not grounded to the chassis.

I don't get it. Take the two connectors and hook them back up to the Ms Pac monitor she fires right up.

??????????????????????????
 
Do you have power to the main fuse? It sounds to me like you are missing the input power to the chassis, if the wires or one of the traces are broken then you'll get nothing when checking for B+. Otherwise as long as the fuse is not blown B+ should be something...
 
I feel like such a meathead as this should be so obvious, but it's not.

I confirmed 129VAC coming across the black wires on the chassis board solder points.
AC Voltage across F902 is 0.000 which confirms the fuse is good.
Double checked and there is no DC voltage at either leg of R901.

I do not see any hairline cracks or fractures in the board, but I'm really finding it hard to believe there's something more going on here. After the entry points of the AC voltage to the board, what should be my next meter test points?

The regulator on the FBO is a STR383, with 3 prongs. Tan to B1, black to E, and red to B2.
Can anyone tell me how to test one of these? There are 6 combinations I can place the leads. What should I be seeing?

Likewise, I'm not sure my previous HOT was bad. In diode mode I get 0V across the thing (2SD869), which matches the one in my working 19" G07 and the one I had in there previously. Out of circuit, I got about .03V on both the old and new and 47 ohms (reversing the leads gave the same results).

Evan
 
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