Page 1 of 1

K7000 weird issues.

Posted: June 28th, 2020, 10:19 am
by Ericthegreat
So I had issues that the screen would cut off and I'd have to kill the monitor off for 20 min or so then turn it back on, I replaced cap (47 I think whatever it says in the flow chart), worked find for a while except I noticed the screen would cut off and I'd need to tap it to come back on, today the monitor just cut off and wouldn't go back on, so I decide to finish the rest of the cap kit, it didn't go on at first but moving the monitor around it came on for about 30 sec followed by turning off, voltage I need to check again havnt since cap kit but was around 160 on b line, do you guys think it's the voltage regulator? I have a angle mfg neo geo so it's really hard to get the the chassis as there is no back door (and it's the 25 in).

Edit: B line is 144 and 164.

Edit 2: if I hit it really hard, it'll come on for 10 sec or so.

I did flow anything that looked corroded/burned, do you guys think it's a bad joint or the voltage regulator?

Re: K7000 weird issues.

Posted: June 28th, 2020, 11:29 am
by grantspain
its going to be a corroded pad, i have seen that on the diode across the yoke header, the width coil and the big resistors- you have to desolder and clean the pad

Re: K7000 weird issues.

Posted: June 28th, 2020, 11:30 am
by nem
If hitting it gets it working, it has to be a solder joint issue. You possibly have a solder pad loose, separated from the trace.

Re: K7000 weird issues.

Posted: June 29th, 2020, 5:04 am
by Ericthegreat
nem wrote:
June 28th, 2020, 11:30 am
If hitting it gets it working, it has to be a solder joint issue. You possibly have a solder pad loose, separated from the trace.
SO the pads were a bit loose on r101, seemed to be still connected, but I exposed a bit of the trace and made a solder blob, same issue, cant seem to figure this one out.

Re: K7000 weird issues.

Posted: June 29th, 2020, 7:28 am
by Ericthegreat
So I found that pressing on the flyback gives a little shock and turns the monitor on, you guys think bad flyback or bad joint? Might just replace the flyback anyway. Just a weird issue, also it's been on for 30ish min now, will it damage anything if I leave it like this?

Re: K7000 weird issues.

Posted: June 29th, 2020, 9:14 am
by nem
I suspect it's a bad joint, although I guess it could be the flyback too. I had one that had crazy focus issues when you lightly touched it.

Anyway, undo the screw holding it in place (if there is one), press the flyback against the PCB, see if the pads lift. If you have a solder sucker, I would suck all the old solder and put new solder in place.

Re: K7000 weird issues.

Posted: June 29th, 2020, 11:28 am
by Ericthegreat
I'll try that, this one gets darker/lighter on touch lol...

Re: K7000 weird issues.

Posted: June 29th, 2020, 6:35 pm
by Ericthegreat
nem wrote:
June 29th, 2020, 9:14 am
I suspect it's a bad joint, although I guess it could be the flyback too. I had one that had crazy focus issues when you lightly touched it.

Anyway, undo the screw holding it in place (if there is one), press the flyback against the PCB, see if the pads lift. If you have a solder sucker, I would suck all the old solder and put new solder in place.
Okay desoldered/soldered it back after pressing it closer to the board, works so far but now there is a lite/moderate buzz/ticking noise, I don't see any arcing though.

Re: K7000 weird issues.

Posted: June 29th, 2020, 10:05 pm
by grantspain
replace the flyback in any case, very cheap to buy in usa

Re: K7000 weird issues.

Posted: June 30th, 2020, 12:25 am
by Ericthegreat
grantspain wrote:
June 29th, 2020, 10:05 MP
replace the flyback in any case, very cheap to buy in usa
Seems to be fine now? After a few days of cap kits and reflow, think I'm going to leave it for a bit, works better then when I first got it.