KevinMullins
Active member
Yes.......
Monitor acts like it shuts off and on real quick?
- Thread starter ArcadEd
- Start date
Yes.......
ArcadEd
Member
Ahh well, guess I probably should have gathered that. Guess the chassis will make a return visit into the cabinet for the 100th time 
.
Does the spike in voltage indicate anything though?
.Does the spike in voltage indicate anything though?
THE COUNT
New member
Not really, you'd be looking for a drop.
ArcadEd
Member
OK, I will do the same test with DC and see what happens.
Ed
Ed
ArcadEd
Member
OK, with DC this time .
Reads 24.9. Everytime the screen collapses it goes up to 25.1. That's it, but it makes that little jump up every single time.
Ed
.Reads 24.9. Everytime the screen collapses it goes up to 25.1. That's it, but it makes that little jump up every single time.
Ed
THE COUNT
New member
OK, with DC this time
Reads 24.9. Everytime the screen collapses it goes up to 25.1. That's it, but it makes that little jump up every single time.
Ed
That is right where the voltage should be. That tiny spike is probably a result of the shutdown, but deff. not the cause.
Alright, who's got the next idea???
ArcadEd
Member
I have some time this weekend to work on this. Anyone else have any ideas?
Ohmerone
Well-known member
Can you measure the dc on the Vertical Ic
the La7831 all the pins,just to get and idea
what all the voltages are?
I would suspect the Vert-output circuit and not the Drive
from the Horiz-Vert drive Ic,but need confirm its good too.
With a O-scope or measure the DC to pin 4 of Ic3
Is c48 100/35v's in correctly and can you sub D25
i have seen it fail in the past,they don't short.
just become leaky,if traces and caps are good and in correctly.
Check The remoteboard pots and connections from chassis.
Was this chassis working in cab for a while?
and then failed with this symptom?
Is the yoke wires have good connections to the yoke
should be the green and yellow wires..on the yoke?
Let us know what you find.
modessitt
Volunteer: Encyclopedia Submission Moderator
Have you gone COMPLETELY over the areas that we circled in the pics above, adding jumpers even if you don't see an issue?
If so, then when I normally see this type of stuff happen, it usually turns out to be the VR (IC4) even if you replaced it already. Sometimes it rectifies slightly off and can cause these issues....
ArcadEd
Member
I didn't make any jumpers, but I tested for continuity.
I will try to get a lot of the information over the next few days and report back.
Ed
I will try to get a lot of the information over the next few days and report back.
Ed
modessitt
Volunteer: Encyclopedia Submission Moderator
Continuity when off does not always mean continuity when on and things heat up. Try wiggling the large parts while watching the solder pads below. if any move even slightly, add a jumper to the next pad...
