John's Arcade Forum - Classic Arcade and Pinball Collecting and Restoring Discussion Forum - RETRO MAME - Nintendo Vs Forum

So I purchased an all original pac-man from a guy who claimed he upgraded the monitor to lcd but original monitor came with the pac. The upgrade was a dell slapped in with a conversion board held in with tape and the old mounts wedged underneath. My plan is to 'shotgun' the k4600 but in the meantime i need to get the wave and tick out of the dell that is currently sitting in the machine. Naturally the coin mechs he claimed worked do not work and there is some cabinet work needed to the original paint. Cab is solid and all parts are there but its rough. So, any thoughts on the lcd dell wave issue? The menu for the monitor does not wave like the gameplay and the speaker also puts out distortion when the volume is raised. Cap the board? Transistor issue? Could power supply cause this?

my guess is the coin switches are not hooked up or getting no voltage.
the wave in the monitor can be caused by faulty fuses, bad grounding, shitty edge connector or bad power brick.

Thank you. I did check the fuses already. I am going to go through the power to make sure the supply is correct. I tried the usual 're-seating' of connectors and such. It seems to get worse the longer it is on. I will continue tomorrow after I take in a few more youtube video's. I want to get caught up on the journey restoration also.

Thanks for the input. I will update as I trial and error for this pac-man problem. I am having a hard time deciding if I want to try a total restore or leave it original and beat up.

dude it takes no videos to know a few things..

Even though those fuses look good, and the contacts look good.. does not mean they are good.
two coming in from the power chord ,  4 over on the right.

Initial voltage tests look good. Fuses good. Cleaned them hoping that was the issue but no luck. I am off to get replacement filter caps. Hope this is all it is. Will keep updating.

Monitor wave (hum bar) can be caused by a bad fuse block or edge connector as Vertex said.

You can read this:

http://www.twobits.com/Humbar/

However, I don't recommend buying anything from them. Go to Bob Roberts instead. :)

Thanks. Ordering the newer block. Been trying to fix all these broke machines i've been picking up. Got the buck hunter running with a cap kit and flyback. Just picked a tron that has a yellow screen. The power supply has corrosion from leaky battery. Original dk with white screen also. Bob roberts will need a big box for my order.

Replaced the fuse block and allthe fuses. Still wavy screen. Going to try caps next. Will update.
I'm off to work on dk. Has a white screen, reading 3.8, 4.3, 4.4 volts on test points.

Yes having the same problem with my Mrs. Pacman. I did find that someone did a really bad repair the the edge of the PCB board so I ordered the repaire kit that Bob Roberts sells to fix the edge of the PCB.

http://www.therealbobroberts.net/pace.html

And the kit to fix the PCB wire harness connector and fues block.....

http://www.therealbobroberts.net/pacfuse_special.gif

I also ordered the PCB cap kit.

I hope this fixes the wave because if it doesn't then I'll be trying to t-shoot the trasformer assymblely in the bottom of the cabinet.

So....it's been a year. I have messed with so many other cabs that pac has sat all this time. So to update; I had previously done all that was stated before. I just recently put a different pac board in and same wave across the screen. I replaced the edge connector (22/44 bob Roberts) and still the same issue.
So... I just ordered a new RFI filter from twisted quarter and a pac pcb "Humbar repair kit" which is just 3 caps for the pcb.
I am running out of options. I am hoping this RFI filter does it. Next would be the power brick but my voltages look good coming out of it. I will update after I receive the filter.
Does anyone have any thoughts/experience with Humbar/wave outside of the normal fuse block/edge connector fix?
Thanks

have you replaced the b+ filter cap on the monitor? or any of the caps on that monitor for that matter.

I still have an lcd monitor in the game. The original 4600 is on the side waiting to be reinstalled. The game was working with no wave when I bought the cab. Started "waving" after I got it home sometime. I thought it may be the conversion board for the lcd monitor. The monitor works well without the input (menu and such). The input from the board (game)is what is waving. I need to put a new connector to hook up the original monitor again. When I picked it up, the previous owner stated the monitor didn't work so he put some POS dell monitor in it with the conversion board. I found a used working chassis for my 4600 but it is not tested yet.

i miss read your last message, i thought you had already replaced the caps. the new PCB caps should fix it.

It seems odd though that I am having the same problem with two different pcb's. I will change the filter then test. And then the pcb caps, then test. I will post the results.

The caps are often bad and are often a problem.

The other issues that can cause the humbar are
poor grounding (bad connection to the harness and to ground)
RF filter PCB still being used. IF that board with the yellow strap is still attached to the harness. throw it out, it causes issues.

No, that board is long gone. Thanks for info. I put a new harness on and checked the grounds. I re-soldered all the wire connections and cleaned and reattached the other grounds. The ground on the plug to the wall (ac in) is good. It's why I posted this. I appreciate all the info. When I get it resolved I will post my findings in a summary. I am trying to do everything I can to stay away from a switcher on this cab. I put one in tron but I also left the (working) original power supply in it. I am using the battery pack card on the switcher for saving scores. (Was having a problem with the lithium battery saving scores on the ps. Mcr's have givien me a problem. Still have that battery in tapper and it's dead after a day or two. And yes, I added the blocking diode).
Thanks again.

Ok. So I replaced the rfi filter then turned it on. Same wave on screen.
Next I replaced the pcb filter caps (4) from twisted quarter thinking this had to be it. And WA la! Same wave....
I am at a loss. So, I went and got a Nintendo 3ds xl and am pondering my Dilemma on some Mario Bros 2. I am thinking the video board for the lcd is messing something up. Going to put the 4600 back in and see what happens.
Thoughts anyone?
(Now on excite bike on pc 10. More calming)

Status update;
The cga/ega/yuv to 2vga board used for the lcd monitor is not bad BUT,... the plug (and transformer) added for the 5 volts incoming to run the board was adding interference. I put a switching power supply in just to test the 5 volts for that board only and the picture is awesome (for an lcd that is). Some semi-permanent modifications for the wiring and pac man is good to go for a while.
I have the 4600 on my bench to put back in. I am waiting for some parts to be able to re-install and the pacman upright should be good for years. New edge connector, fuses and block, rfi filter and soon to be rebuilt 4600 all matching numbers back in original condition (including paint and t-molding). Some switches and wiring repaired.
Thanks for the advice and input guys.

Here is what I am thinking. I just had a monitor on the bench this past weekend that had a humbar that didnt seem to want to go away with the standard cap kit + filter cap.

The voltage regular was not working, it was shorted and was passing through AC.

My guess, and i think this is very likely, is that the vreg on the pacman board is dead. The vreg transistor is the one on the heatsink near the caps. I would do a multimeter diode test on it and i bet you will find its shorted. the transistor is a TIP31 https://iankellogg.com/index.php?main_page=product_info&cPath=17_20&products_id=91

After pac finally being "fixed" it is dead again.
It mysteriously started flashing fruit on the screen. It looks like it is cycling through all the fruit and ending on cherries for a moment then starting again. It's in about 7 spots randomly across the screen.
I thought it was voltage, it is not. I changed the z80. Same. Sync bus, same (although I can't verify the replacement). So, my plan is to change EPROMs and then get out the probe.
Any suggestions?
(Was a bad day. Lost pac, popeye and Mario. Frogger sprite problem just a few days ago).

sounds like eproms to me.

Well, I am using this as an excuse to get a logic analyzer. I have a probe but I have been itching for a new toy. I have an eprom read/writer but I am setting up a new (old) computer as I have never used it. I am a few decades behind the times but as they say 'better late than never'.

you aren't going to want to mess with a logic analyzer. Seriously, unless you are working on a nintendo game it isn't worth the hassle. I RARELY pull mine out

Dam. I already ordered it. I was hesitant until one too many beers last night. Lol.

On a positive side (sort of), I have a few Nintendo boards that have flaked out on me.

Well which LA did you buy?

And how's your knowledge of DMA?

Agilent 16702 with 16556d card. being as DMA can be quite complex, I would consider myself a novice. I had vocational electronics training many years ago. It is just a fun hobby for me now. My background is industrial maintenance. I usually do ok with my logic probe but I have been interested in learning a lot more. My last bit of gadgetry was a Sencore CR 7000. Something I was not too familiar with but I tested every tube I have with that thing. And it's awesome! I feel a lot more comfortable with it now. Working with it helped me understand monitors and tubes functionality much more. I am hoping to understand the processes on these boards more than I do now. Again,....novice.