Monitor Issue

[hendrix77]

Hi
Im new to this site and also new to real arcade hardware. just got hold of a cocktail cab from ebay,

the original board was completed screwed so opted to go the 60 in 1 route. not perfect but just wanted it so i can at least play some games. so got my jamma harness wired to monitor using corresponding wires i.e blue red black and white. then power cables. picture comes on but there is a weird roll horizontally and with three or four white lines to the right looking at monitor vertically.do you think this monitor needs a cap kit ? the chassis is a sanwa 1416 and a chunghwa tube. cant find any info on chassis. is it easy to cap it ? thats providing i can find a kit for it. cheers

 

[obcd]

The roll could be the vertical frequency potmeter that needs a little adjustment.

Do judge about the white lines, a picture of the image might be a big help.

 

[anj]

can we get a photo as it could be you have the earth and sync mixed up ,

 

[anj]

also is switch 2 in the off position

 

[hendrix77]

hi
thanx for fast reply mate. where would i find the pot ? sorry im a complete beginner on monitors cheers

 

[hendrix77]

Hi this is the pic of screen. hope this helps. do you mean switch 2 on jamma board ? if so yep in off position. you guys rock btw never had such a fast response in all my life cheers

 

[gunblade]

those icade boards do that on alot of monitors,bet it goes when you select a game?
you may be able to reduce the lines by either screen volts or vertical size

 

[hendrix77]

Hi
Yeah they do go on most games but some have horrible roll.out of interest how do you reduce volts ? Ive noticed there is alot of ground wires to coin mech/joystick bolts/etc and a noise filter box do I need all that stuff ? Wud these effect it ? I read in the manual that board shouldn't exceed 5.something volts.

 

[gunblade]

the sanwa chassis may need the sync wiring linked for vertical and horizontal sync-after you have looked for and adjusted the vertical hold/frequency pot

you will need to purchase a multimeter to read the +5 volts,you do so at the edge connector rather than the power supply for a more accurate reading

every switch needs a ground wires,the wires to metal work are earth-each area of exposed metal work on a cab does need to be earthed.Things like power supplies and monitors need be earthed to prevent interference as well as for safety

btw read exactly what i say,i said screen volts-its not volts.Screen volts is the adjustment on the flyback transformer below the focus adjustment.Making an error like this could be dangerous,someone once decided for themselves that screen volts was b+ and started messing with that-could have hurt the monitor and himself

 

[hendrix77]

Ok thanx trust me I wont be sticking my fingers where I shouldn't be. It scares the sh*t out of me lol. Ive noticed that when I adjust the brightness on the flyback it produces alot more white lines when its very light. This also happens on all games but there are also not symmetrical. is this normal ? Cheers p.s im completely new to this and I appreciate that your helping me. dont worrie I wont do anything that im not completely sure about cheers for caring

 

[obcd]

Yes, the white lines you see when you turn up the screen voltage to much are normal. They are called the flyback lines. When the beam lightning the picture tube returns to it's upper left start position, it's supressed. When the brillance (screen voltage) is turned up to high, the beam isn't fully suppressed anymore and that causes the lines you are seeing.

Your image looks to small from top to bottom. Maybe it's done on purpose as there could be a smaller bezel above the picture tube, or maybe there is an issue with the monitor chassis. As your picture on this forum is vertically stretched, it's hard to say if it's to small in vertical or horizontal direction. Horizontal is the largest distance of your picture tube. Vertical is the smaller distance. If it's vertical, it could be due to some capacitors on it's way out. I have seen such white lines on a TV, and the problem was a bad capacitor.

I have no experience with that chassis.

There should be a vertical size adjustment potmeter. If you can't adjust the picture to become full screen with that, there is a problem in the monitor chassis.

obcd2015-03-26 08:42:09

 

[hendrix77]

Hi
Yeah I cant get it to go full screen and the bezel is for the whole viewing area of the screen. changing the caps is what im leaning towards. I want to do this anyway so I know ive covered this and then work for there. Problem is I cant seam to find any info on the chassis at all online. It wud be so easy to whack a lcd in there but I really dont want to do that. For one as everyone knows it looks nasty and I see fixing the monitor a Challenge

 

[obcd]

Lcd's nowadays have a 9:5 dimensions. Crt tubes had a 5:4 dimensions. If you show a normal picture on such an Lcd it will be stretched into the horizontal direction. Furtheron, Lcd's only work well when they are feeded with their native pixel resolution. If they have to upscale, it looks ugly as you say. There do exist special arcade tft monitors that can handle lower 15 and 28k resolutions and have a larger viewing angle, but those are expensive beasts and they don't have the correct dimensions either. The schematics can be a big help, but even without them, you coan make a list of all electrolytic capacitors that are on the chassis. Make sure you note their working voltage as well, and notice if they are in thight space so that replacements shouldn't have a bigger size.

You will especially need to look at the capacitors surrounding the vertical deflection ic. That ic is normally mounted against the chassis, or it has a cooling fin mounted onto it. Just check the numbers of the ic's you find on the chassis until one says it's the vertical deflection amp.

Make sure you are aware of the need to discharge the picture tube before you remove the anode connection and the chassis. Discharge it again before you reconnect that anode connection as most tubes build up some voltage when left idle shortly after use and discharge. Also be aware that the polarity of electrolytic capacitors is extremely important. If you mount one the wrong way, it won't forgive your mistake.

 

[hendrix77]

Ok cheers for the info I will try and do this tonight. Yes I will discharge before taking apart and good advice to do it again. There is an old tv repairman up the road from where I live. Considering popping the chassis in to him to replace caps. Ive done soldering before and ive lifted traces. If I ended up doing that I wud be gutted. It would be so cool to get this working

 

[obcd]

It's an option if he is not tired of doing repairs. Just tell him you have a vertical size problem.

You might make a list of the needed capacitors and order them, unless he prefers to do that himself. It can be time consuming to order new capacitors, specially if you order some with a longer lifetime. the expected lifetime can vary from 1000 hours up to 10000 hours. That's at it's maximum operating temperature, so they should last longer.

 

[hendrix77]

haha yeah he might do it ill try and ask although ive managed to remove the chassis and saw the solder points are fairly big and i mite try to cap myself. heres a few pics

 

[hendrix77]

 

[hendrix77]

also noticed that there is a h position with different pins on board and a h width that i think you can adjust any thoughts ? cheers

 

[obcd]

First, I would blow the dust out with a compressor.

Your size problem looks vertical, not horizontal.

I assume you tried to correct the situation with the VHeight adjustment. If you turn that one, you can see the picture become bigger and smaller, but even on it's maximum, it's not covering the whole picture tube area.

On the left of the hposi jumpers, on the first picture you have some components mounted on a heatsink. I would start by replacing all the capacitors surrounding that area. You have that ic in a socket under it approx in the middle of the pcb. What do the numbers on that read? (I admit I am to lazy to import the picture, rotate it and enlarge it to try to figure out myself.)

 

[anj]

hears food for thought . the 60in 1 board can cause this fault its self . i have had this happen . plug another jamma game in and see what it douse