Any idea what monitor symptom this is? (K7000)

[danielm7999]

Yeah I see what youre saying.

I had to put the multimeter dial on 200v ...and I got 22.5 volts. (IC3, pin 6, monitor turned on, black lead to ground, red lead to pin 6.

[ed12]

well then u know what to try
order 1 up and see

ed

[danielm7999]

Thanks buddy, will do. I'll check back in after I swap the new one in. Really appreciate your help. (Check your email when you get a chance)

[ed12]

its np and will do

ed

[danielm7999]

Got the new IC in the mail, I noticed the old IC has pins cut off of it. Unless theres a detail that Im not aware of, Im assuming I should cut off the same exact pins on the new one and fit it on the board exactly as the old one was, correct?

[ed12]

the oem, was shipped with the pins cut for a reason..
i will double chk
is it a oem chip or a replacement for some other mfg?

ed

[danielm7999]

I bought from arcadepartsandrepair.com. He's had good quality parts of everything Ive bought from him. Not sure if its OEM though. They sure look identical except for that "D" on the new one, instead of a "J" on the old one.

The chassis only has 7 holes, so I was assuming thats why they originally cut the 3 pins. I figure those particular pins are useless on the K7000. But thats just my guess. I've done some looking but havent found anything on this yet. Maybe Im looking in the wrong places.

**EDIT: I found this comment from Ken Layton on another forum: "You match up the old LA7831 with the new one and see which terminals you are to chop off of the new one. Then everything matches. Take my word for it. I think it was terminals 1, 2, and 10 get chopped off."

But I'd just assume take your word for it if you disagree

[danielm7999]

Im gonna go for it... Will let you know what happens

**EDIT: Bummer, still no changes with the screen issue. I also checked the ohm's on the red & green wires from the yoke and those still read OK so theres no issue there. I guess I'll try changing all the Bob Roberts caps out, since I heard someone say theyre cheap & low quality.

[ed12]

no i just chking
glad u found the info
and yes thats what they told to do (chop)

ed

[danielm7999]

Damn, I guess its not the caps either! Just put a new set in and no changes.

I suppose I'll try to reflow the IC2. And maybe replace the C51 tantalum. Maybe the IC2 as well. Maybe when none of that works I'll get some lighter fluid and set myself on fire!

[danielm7999]

Here's what the problem looks like with a regular arcade JAMMA board connected:

The screen has a little bit of a different effect, but its basically the same problem. So I guess now we know that it definitely has to do with the chassis and nothing to do with ArcadeVGA/Windows. Again, none of the pots will solve this...not even the 50/60 pot.

Has anyone seen this kind of screen effect and does anyone know the technical name for it?? (ex: "vertical fold over", "vertical collapse"?) If I have a name for it then that might help to find better search results.


Here is a brief recap of this cabinets history from the time I got it until now:
1. When I originally got the cabinet the flyback was probably blown. CRT was bascially dead. Very dim screen. Replaced flyback, did cap kit, swapped tube with a TV tube. Used the TV yoke because the readings were acceptable and very near the original. Arcade game looked brand new again. Great colors. Needed a little degaussing but picture was perfect after degauss.
2. After that, once in a while screen would do a quick 1 or 2 second flash at random points while playing it. This usually seemed to happen more often during points of a game that had a lot of action going on. Sometimes immediately following the flash the screen seemed to resize itself a little smaller and maybe even a little darker than it was before, and sometimes it would start to wave like a water effect at this point...then after maybe 30 seconds it would flash and go back to a normal looking screen again. Blowing a floor fan into the cabinet seemed to alleviate this considerably, but I'm not sure if that was true or just coincidence.
3. I decided to change out the H.O.T. / voltage regulator /and  B+ filter cap to see if it would stop the problem. Instead I ended up with this after putting those in: PC: JAMMA:
4. None of the pots will fix this. Not even the 50/60 pot
5. I tried putting the original old  H.O.T. / voltage regulator /and  B+ filter cap back in but that didnt fix it. So I put the new H.O.T. & voltage regulator BACK IN the chassis again and thats how its set up now. Old B+ filter cap is still in the chassis, I did not put the new one back in again.
6. B+ reading was 161.9 on one terminal of the 180ohm resistor (seen in pic) and 120.2 on the other terminal of that same resistor. Thats with the new voltage regulator installed (and yes, its a 30130).
With the OLD original 30130 regulator, the B+ measured 161.3 on one side and 107.3 on the other side
7. Q9 tested OK both fowards and backwards.
8. Tested IC3 - I got 22.5 volts. (IC3, pin 6, monitor turned on, black lead to ground, red lead to pin 6.
9. Changed out the vertical IC 3 with a new one (same model # as original)
10. Checked continuity on all the joints of the board. Reflowed some old joints.
11. I did another cap kit with better quality capacitors

No luck so far.

[grantspain]

if you remove video signal and increase screen volts to dispaly a raster do you see a similar issue?

[danielm7999]

It's still doing the same thing with screen voltage up and video input on chassis unplugged:

What does that rule out exactly? It doesnt mean that my tube/yoke is screwed does it?

[grantspain]

i think the issue is on the vertical position or vertical hold circuit

do either of those pots actually do anything

[danielm7999]

Vertical position pot moves the image up and down slightly. Vertical hold pot does nothing at all.
Changing V-Size to its full extents does this:

**EDIT - OH SH!T, the V-Hold pot has a tiny crack that is preventing one of its legs from connecting to its internal mechanisms. Damn!!
Youre a lifesaver bro! Ed too (my fault for barking up the wrong trees on this)! I'll see if I can fix this without having to buy a new one. Will report back when fixed.