Author Topic: Monitor screen doing the "hula" sides rolling (Read 3575 times)

rfr341 · « **on:** June 01, 2006, 03:41:26 am »

Hi I was wondering if anyone can help me out. I have a cabinet with a wells gardner 4600 in it and the tube is on its way out so I have an extra monitor with a wells gardner 4900 chassis so I am going to put the monitor setup with the 4900 in to my cabinet. My problem is when I turn the game on I can see the picture fine but the screen does the "hula" by which I mean the sides of the screen move in and out with a slow wave moving up and down the screen. I have Randy Fromm's flowchart and have checked everything that he says to on his flowchart and all seems fine but I can't get rid of this problem. Does anyone have an idea what could be causing this problem. Your help would be greatly appreciated.

Gaston77 · « **Reply #1 on:** June 01, 2006, 06:06:44 am »

Hi, so if I understand correctly; you are replacing the ENTIRE monitor? The 4600 out and the 4900 in? If that is the case, you had better give WG a ring, they can tell you what's going on.
If you have taken tube from the 4900 and use the chassis of the 4600 (is that even possible?), then I am sure that this is the problem. Either way, give tech support a call, they'll have your problem sorted in no time.

Good luck and let us know how you fare.

rfr341 · « **Reply #2 on:** June 01, 2006, 11:25:05 am »

What I have done is replaced the entire unti chassis and and the tube, so the monitor setup I am using now is using a 4900 chassis with the tube it came with. I have gotten rid of the 4600 setup all together so I have not mixed and matched the parts.

grantspain · « **Reply #3 on:** June 01, 2006, 01:57:19 pm »

sinc,earth or cap problem or if there is a transformer near the yoke it will cause a similar problem-start with the simple things check the sinc connections are correct then check the earth to the chassis(some need em some don't),obviously if a transformer is near the yoke then move it away,then of course if none of that cures it then its likely to be an electrolitic,most likely on the mains smoothing side of the chassis

rfr341 · « **Reply #4 on:** June 01, 2006, 05:51:03 pm »

Thanks for the help, I have put a new cap kit on the board and I am not sure what you mean by "mains smoothing side of the chassis" can you explain that term for me I am new at this stuff.

Kevin Mullins · « **Reply #5 on:** June 01, 2006, 11:34:14 pm »

Don't quote me on this...

"Mains" being the 120V power goping to the chassis.

"Electrolytic Smoothing" being a capacitor somewhere in the power supply portion of the chassis.

Do a good "wiggle" test while the monitor is on and look for any fluttering or changes while you are doing it. (to look for bad connections, cold solder joints, etc)

Check the B+ voltage to see if it's up to speed, correct and stable.

rfr341 · « **Reply #6 on:** June 02, 2006, 01:30:44 am »

Thanks for Kevin for explaining that term to me.

I checked the earth ground, the sync and have made sure no transformers are close to the yoke with no luck. I have put a cap kit it in and I have followed all the stuff on the flowchart with no luck. I have checked the power readings like the flowchart says and they are all fine. I will try the "wiggle" test and see if that works, I have gone over the board checking for bad connections and solder joints and have found nothing out of the ordinary. Any more ideas. I will check B+ voltage and see what it is.

grantspain · « **Reply #7 on:** June 02, 2006, 03:48:18 am »

how bad is the wave effect?

rfr341 · « **Reply #8 on:** June 02, 2006, 11:06:21 am »

It is pretty bad.

grantspain · « **Reply #9 on:** June 02, 2006, 01:14:28 pm »

its possible that this is a fault on the power supply part of the chassis most likely a large electrolitic cap,you said you installed a cap kit does this mean you have changed every electrolitic cap on the chassis,also do you still have this effect when the rgb signal is disconnected

rfr341 · « **Reply #10 on:** June 02, 2006, 08:37:20 pm »

The only Cap I have not replaced it the big black one which I may try doing later tonight.I tried to unplug the rgb and all I got was the raster lines across the screen with the brown back ground of the game but it was hard to tell if it was still if the sides of the screen were moving in and out. I will let you know how it goes once I replace the big black cap.

rfr341 · « **Reply #11 on:** June 03, 2006, 12:08:58 am »

Well I tried to replace the big black capacitor and it did not help, so I have changed them all with no luck. I am not sure what else to try, do you guys have anymore ideas? I am considering signing up on Randy Fromm's website for $40 to get information not only on this but just to learn, are any of you signed up there? If so what do you think of it? I was thinking of either buying his big blue book or signing up on his website because all the info in his book is on his website and it is cheaper than buying the book.

SirPeale · « **Reply #12 on:** June 03, 2006, 12:57:33 am »

I had a monitor once that had major hula. Was certain it was something to do with the HOT, but it tested fine.

Turned out to be a combination of a bad joint and a pulled trace. Only found it upon touching up solder joints, and it popped off the board. Once the trace was fixed, the monitor operated without a hitch.

So since you've done all the caps, start going over the joints in the power supply circuit, esp around the HOT.

dabone · « **Reply #13 on:** June 03, 2006, 11:12:49 am »

Check the powersupply voltage at the blue lead of tr502, it should be at 127v. If it's not, check tr501 and tr502, and change caps at c608 and also c605.

If that doesn't work..

Check TR 351 - TR 354 Try replacing C356, C359, C362.

And remember kids.. This is susposed to be fun!

later,
dabone

rfr341 · « **Reply #14 on:** June 03, 2006, 10:15:59 pm »

Hey dabone thanks for the info but I think the stuff you told me to check is from a wells gardner 4600 chassis and I am working on a 4900 chassis, I looked for a few of the caps and they are not on the 4900 chassis. I could be wrong and if I am my apologies and if I am not do you have any advice on what I should check on the 4900.

dabone · « **Reply #15 on:** June 04, 2006, 10:17:59 am »

Ok, lets try this again, not hungover.

Check the reg. ps at resistor R503 *The big 150 Ohm, 15 Watt one), the end nearest the fuse should be +130V.

part1

If the voltage is low check the input voltage on the resistor (other end).
It should be 145V. If it's low then C505 might be bad. If it's no voltage, then check R601 to see if it's open.

Part2

If the voltage is +145 then you have a bad ic 501. Also try C507.

Part3

If the voltage is +160 then check the jumper wire J33 and others on the 130V trace, These are located on the edge of the pcb. If these are ok the check your chassis for cracked joints (again). Then check the voltage on the metal can of Q352. If it's at 160V then test Q351, and R363,look for bad connections on T351 and also change IC301.

Later,
dabone

rfr341 · « **Reply #16 on:** June 04, 2006, 02:58:59 pm »

Thanks for the info dabone, I checked all that and eveything seemed to be fine. I'll check it all again just to make sure but if anyone has anymore ideas please pass them on.

grantspain · « **Reply #17 on:** June 04, 2006, 03:00:55 pm »

i know its a long shot but try disconnecting the degauss coil from the chassis

rfr341 · « **Reply #18 on:** June 04, 2006, 07:29:29 pm »

Actually I have already tried it and it did not work.

Kevin Mullins · « **Reply #19 on:** June 04, 2006, 08:26:29 pm »

Just curious... but have you tried a different signal source?
Different game PCB?

And are ya certain this is all correct as far as the tube-yoke-chassis?
(I know you had some mis-match issues awhile back with that 4915 medium res)

rfr341 · « **Reply #20 on:** June 04, 2006, 09:37:16 pm »

Hi Kevin, I have tried a few different game PCB's on there and I get the same result. I know the chassis I am using is a standard resolution chassis because I took the chassis out of my mat mania game and tried it on this monitor and I got the same "hula" in and out wave on the screen. I am going to take the board of and check all the solder joints again and a few of the transistors again. I will let you all know how it goes.

rfr341 · « **Reply #21 on:** June 05, 2006, 02:18:41 pm »

Well I am not sure what to try next. I checked over all the solder joints and Q201 & Q202 and everything is good but I still have the Hula on the screen. I think I am going to sign up on Randy Fromm's site and if anyone has more ideas let me know.

rfr341 · « **Reply #22 on:** June 08, 2006, 09:20:37 pm »

Good news I got rid of the "hula".

I decided to check some transistors and it turns out transistor str381 on the ic 501 was bad, replaced that and now the monitor works great! Thanks to everyone for your

help.

Kevin Mullins · « **Reply #23 on:** June 08, 2006, 10:31:08 pm »

Good on ya !!
Now you're getting the hang of this monitor stuff.
Was that the actual transistor number or the location number.
(my main PC is down.... can't get to the schematics to see)

rfr341 · « **Reply #24 on:** June 09, 2006, 01:12:38 pm »

Hey Kevin, I think I am getting the hang of this monitor stuff

That I believe is that part number because the str381 was written on the transistor, it sure does feel good when you figure it out and fix the problem. Now I can start to clean up my cabinets cosmetically.

Kevin Mullins · « **Reply #25 on:** June 09, 2006, 01:35:34 pm »

Ok.... figured it was the transistor number itself.
Gonna keep a mental note on that one.

Oh.... and don't ditch that 4600 you have. They're not hard to work on either. Those are common on some of the older machines. You may want to do a cap kit on it sometime and hang onto it.

yeah.... it seems to be the cosmetic part of these projects I never really get around to.

But the kids around here still enjoy them.


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