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Issue with Sony Trinitron Monitor - Wavy Display
Mr. Peabody:
Look on CL/local 'groups'. Someone here in your area might have one.....
nick3092:
I'm reviving this thread, to see if I can maybe find anyone who has an idea of what is going on with this monitor. Or can at least help me troubleshoot it further. I was unable to find anyone around here who still works on CRT monitors, so self repair seems to be the only option here. But I don't know how to troubleshoot a CRT.
Between October and now, I have ruled somethings out. I found the voltage readings I was getting earlier in the thread when bench testing the power board were inaccurate on the bench. The board does not like being run outside the chassis for somereason. The readings look very good while the monitor is in the chassis:
-15v rail (measured -14.5v)
+15 rail (measured 14.5v)
+80 rail (measured 78.2v)
+200 rail (measured 199.3v)
I figured out how to disconnect the fly back so I could remove the deflection board. So I recapped the board. No change. Since then, I have replaced pretty much every electrolytic capacitor in the monitor, board by board, checking the monitor after each one. No change after any of the recaps. I looked over the deflection board for any broken/cracked solder joints, I couldn't find any. To be safe, I reflowed a bunch of joints on the board, focusing on anything attached to a heatsink.
I did notice that the ripples running up and down the left and right sides of the screen change slightly if you mess with the geometry settings. Except in one spot on the screen. This spot on the screen never changes. Its always the static plateau, valley, plateau, valley while adjusting it. Not sure if that means anything.
Its possible whatever this is, is a defect across all similar Sony chassis. Someone else found an eBay listing of a Sun monitor with a Sony chassis exhibiting the same thing. Although, it looks worse than mine. And according ti the service manual, for that monitor, the deflection board is about 99% identical to mine. So my money is on a common issue with this monitor. The million dollar question though, is what?
https://www.ebay.com/c/13014969428
I have a scope and can post screen prints of any points of interest. but I'm not that great with using it or troubleshooting CRT's. So I need to be told exactly where to check, preferably with what scope settings as well. Due to the construction of the monitor, its almost impossible to get to the back of the deflection board though, so almost any measurements have to be taken from the component side.
This is a really nice 21" monitor and I would love to be able to get it going again. My cabinet has been idle way too long. I could have used the distraction of playing it the past 2 months. Hopefully someone can help me fix this. I know its a bit more complex than your usual arcade monitor, but the core functionality/troubleshooting should be the same.
Thanks!
Zebidee:
I'm shooting from the hip here, because I don't know your monitor at all and I'm far from the most knowledegable person on these boards, but I would have a look at the horizontal deflection circuit - identify the ICs that do the job, "horizontal deflection oscillator", nearby components and power supply to that part of the circuit.
If you have horizontal deflection then you have power (and obviously vice-versa) as horizontal deflection drives the power circuit. If the B+ looks good then it must be in the deflection circuit. Fluctuating power might possibly cause the problems you have, but even then a possible cause could be the horizontal deflection or the part of that circuit (optocoupler) which feeds status info back for regulating the B+.
That is a long way of saying if you have power at all, then the part(s) responsible are failing but haven't completely failed yet.
It is pretty base advice, but some "swaptronics" (swapping out suspect parts like ICs for known good ones, not just electro caps) in horizontal deflection area might reveal your problem or at least rule some things out.
nick3092:
Turned out to be IC007. the deflection processor. Apparently Sony used this same design (N3 chassis) in several of its own and re-branded monitors, and it was quite common for this IC to fail in that chassis and cause these symptoms. I found an NOS one for a reasonable price and found someone local who does SMD rework for a reasonable price as well.
Monitor is now happy, and so am I.
Zebidee:
Good News!
I had a feeling it has the horz IC as it was a Sony. I've had techs tell me similar about Sony PVMs.
I recently remembered I have a Panasonic TV in an arcade cab that had symptoms like yours, but the solution was power supply related - had to replace a large blue ceramic disc cap near the huge resistor at the end of the B+ section. The blue ceramic cap had been pushed against the resistor's leg, and the insulation had been worn/melted away, thus the emerging problem. I replaced the ceramic cap with an NOS one, and couple of other aging electro caps, and the problems went away.