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Odd D9200 behavior
lilshawn:
--- Quote from: lilshawn on February 01, 2024, 01:00:32 pm ---maybe at lunchtime i'll pick up a can of air duster and turn it upside down and give a few things a blast of liquid CFC and see if it smartens back up if something in particular gets cold again.
--- End quote ---
so, I did in fact grab a can of duster (a couple days later... boo other things :( )
and also been sidetraked with other projects... but
i started out gingerly spritzing a few areas and select components I thought it might be, to see if it changed at all. and it did not.
then i started blasting some of the entire areas i thought might be responsible... still doing it with nothing changing.
i decide eff it, just absolutely hose literally every square millimeter of the board with liquid refrigerant all over the place, all at once, till the whole board was frosty... like i literally was waiting for the board to short out. (it didn't)... but i'll be damned if it's still doing it like it DGAF. (screen did distort geometry a bit from timing components being sub zero and being way out of spec and some being superconductors now.)
blasted the yoke down... it has to be that right?
no. change. at. all. BRUHHHHH. :banghead: where the hell is this forsaken jitter coming from!?!? it's not my output signal... and i did rule out sync doing it with the scope before. i can hear the variance in the scan timing when it does it, so it's being produced in the board somewhere.
it doesn't do it when it's "cold"...it does it when it's "warm"... but also does it when it's COLD? so... not heat related? time related? charge related? something not affected by heat.
i dunno man. :badmood:
grantspain:
does it do the same without video signal?
lilshawn:
i am currently testing without signal as I type this.
oddly, I couldn't get a "no signal" box to display on the screen. I initially thought that it didn't have one, or that maybe it shutdown and went to sleep because of no signal input... and right now the monitor is on the floor, and i couldn't see the power LED on the board from where i was positioned over it.
i pulled the plug thinking about what to do and indeed it was still on. so i plugged it back in and was just going to crank up the flyback till i could see a raster and go from there. i turned the flyback up a little and there in the darkness was the no signal box.
it turned it up actually quite a bit. i did turn it up enough so the black is still black and the no signal boxes are bright.
so it was adjusted "correctly" for 31k but just didn't have enough at this resolution mode... i mean i expect to have to move some stuff around when changing resolutions...but not normally the flyback screen control... usually that's all handled separately. never touched the sub-brd control...i dunno if that has anything to do with it...never had to mess with it. just a sub brightness adjustment i gather.
in any case, this monitor never even ran this at anything but 31k (it's a big buck hunter pro monitor.. i'm pretty sure it's 31k vga) so i don't know how it's supposed to act in 15/25k resolutions.
my computer signal i was feeding in is from my desktop, 640x480 60hz so it's for sure at 31k. I did hook up the scope to the horizontal video signal coming in and it was rock solid with no evidence of noise or anything. the horizontal pulses that the flyback shares from the control IC are solid too.... it's just something in horizontal deflection doing it.
I assume this mode it's in is 15k. it's been running about 15 minutes now as i've been typing this. it hasn't manifested any jitters yet. the weird line in the exact center scanline at the middle of the screen has. i don't know if it's related or just something with it's vertical driver IC (i have seen some of those do something like this before. it's not a real concern if it's not related. the jitters make the monitor unuseable.
https://photos.app.goo.gl/CmQXs7z28PBSEwv37
so now i'm wondering is there maybe a capacitor or diode or something that is activated in the 31k mode that is making the screen really bright in 31k mode and by proxy, causing the jitters? i mean, assuming the jitters don't appear here in 15k mode.
i'll let this run a while and check in on it in a bit and update what happens.
thanks grant ;) always helps to have another set of eyes looking at a problem. i get blind to obvious things often, especially when it's been this long i've been looking at something.
EDIT:
after about 45 minutes or so i'm calling it good in this "no signal" mode it's running in. there is no evidence of jittering. Just the weird line. I do have to run out of the shop for a few hours and i'd rather not leave this unattended... so for now, i'm shutting it down. the saga continues.
grantspain:
when signal is applied does the on screen display work?
lilshawn:
yes, the OSD does work. 100%
During my o-scope testing, i had gone in and adjusted a bunch of stuff to see what affected the waveforms on the scope trace i was looking at. (what things made the wave level bigger, longer in duration, changed the slope etc.)
i only have to bust out the scope every few years, so i try and learn as much as i can when I do.
i was curious if you know of any kind of adjustment in the service menu mode that might have gotten changed that might cause this, i know nothing of the meanings of most of the settings in there so i never bother messing about in it.
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