#1084 monitor flickr-HELP
13 messages in this thread
Can anyone help me find info on a Flashing/Flickering, sometimes not-working
monitor fix?? I have seen it posted (how to fix) before but cannot find it now,
even with amigaFF.
Please help
Thanx in advance
Zeddock
Zeddock,
The first thing I'd look at would be the flyback transformer's solder
joints. They tend to break. I suppose the high frequency vibrations in the
transformer put a large amount of mechanical stress on the solder joints.
Once they break, they get intermittant. The resulting arcing makes things
worse by burning the connection. It's fairly simple to resolder the
connections, the biggest hassle is unsoldering a metal shield over the
bottom of the circuit board. BTW, there are some capacitors in that area
too. I've seen them break their joints as well. And of course the
obligatory warning: There's dangerous voltage inside monitors. CRTs can
hold charges for some time. Proceed ar your own risk.
-Jim
MOS via Autopilot & Amiga
I have a similar problem I guess. I was trying to solve one at a time (my 1000)
but what the hell… My 1084S-D1 monitor starts up with no blue color. After a
period of time (afways different but usually less than 10 minutes) the blue
comes on like normal. Am I losing the blue gun or could I have a bad connection
somewhere? Thanks! -Dan
It's possible the gun is going out, but probably not. They all share a
common filament. More likely a problem in the blue output path. The
drivers for the 3 guns are all on the neck board that plugs onto the CRT.
Since they're all the same, it's fairly easy to scope backwards and
compare. Finding the parts is more difficult. 🙁 If you use a greybar
program like VTOT or even just draw some bars in DPAINT you'll have a good
signal on all 3 colors. But since you have to do this with power on the
monitor, it's not for the faint of heart…
-Jim
MOS via Autopilot & Amiga
i might let the professionals handle that one. i'm really hoping it's juse the
cable… [D [D
A bad cable is possibility, but from your description it didn't sound like
it. Try using the composite output of the computer when the thing acts
up…. or swap the cable if you have a spare.
MOS via Autopilot & Amiga
Funny thing… today for the first time in two weeks it booted up with blue!!
I'm so happy!! I hope it lasts! If it doesn't I'll mess with it.
I have seen the drivers fail, but if it fails again, wiggle the cable,
sepecially at the ends. It's worth a shot before going into it. BTW, have
you tried this monitor on another computer… it could be the computer
losing a color too…
-Jim
MOS via Autopilot & Amiga
well Jim Its been behaving itself for three days now. I'm not gonna disturb it
unless I have to. (Which I will when I have to test that 1000). BTW I tried to
test the chip as you suggested but I really dont know how to use the scope. At
the settings you suggested I got total kaos no matter what I touched with the
probe. (anything conductive). I guess I'll need to get a scope tutor before I
go any further with the 1000. Thanks! -Dan
It's a fundamental rule of electronics that "If it's working, don't mess
with it." On the scope, try looking at the clock line on that '157 (pin
1). Then adjust the hoizontal sweep rate to something where you see square
pulses. You might cut the vertical down to 2v/div. You are grounding the
scope probe to the computer?
-Jim
MOS via Autopilot & Amiga
Dan:
When dealing with signals such as with video or logic, you need to synch the
scope to something. In the case of logic, it is best to connect a probe
between the external synch connector and the system clock. For video, try to
find the horizontal synch or vertical synch, depending on what signals you are
looking at, to the external synch.
The reason for this is that although almost all signals are _supposed_ to be
some particular frequency, all electronics drift off after a while. I've yet
to see any electronic device exactly on frequency, even after I've tuned it!
By locking the scope to some original source in the device, you are seeing the
signals in relation to how the whole device is timing itself.
BTW: In case you aren't aware of it, there is a position on the horizontal
display width usually marked EXT. That is the position to use when synching to
an external source.
I hope this helps.
"The first lesson of economics is scarcity…. The first lesson of politics
is to disregard the first lesson of economics." (T. Sowell)