Dokert
Well-known member
If the fuse is blown again, definitely your fly is bad. If the fuse is not blown test R908 and the four diodes on the left side of the chassis. (I forget their designations)
Electrohome G07 missing B+
- Thread starter jehuie
- Start date
Put your meter across that big filter cap.....DC volts. You have juice there?.....the little fuse is blown. (this test is with no power applied).
Edward
Peale
Active member
Whenever I power up a chassis I always watch the fuse to see what it does. Saves a lot of guesswork.
Dokert
Well-known member
OP
OP
Thanks again gentlemen. The fuse is blown. Ordered a new fly (and some other goodies) from B.R. last night!
Peale
Active member
That bright flash usually gives it away.
What I'm saying is most people seem to install their chassis and not watch it as they power it up. Keeping your eye on the chassis on initial powerup is important - fuses can blow, components can smoke - you never know what's going to happen. So make it part of the routine.
Dave, of course YOU know this, but a lot of others seem to take it for granted.
OP
OP
Yes, I always watch the chassis any time I do work on it. Look for smoke, sparks, etc. This time I didn't see the fuse blow though. Not sure why I missed it but it's clearly blown.
OP
OP
Swapped the flyback and now I have a pic but it's massively bright and washed out. Turning down the screen control doesn't help much. According to the magic flow chart, this sounds like it could be a bad transistor X303. I'll try tracking one of those down now. Perhaps Fry's will have them....another day...
Peale
Active member
I had a similar issue on a G07-CBO recently. When I closely examined the traces around the flyback I noted cracks in a couple of them. Repairing these solved the issue.
Also: whenever you have a chassis out and your iron hot, start going over solder joints. I always do every joint on the neckboard and the power supply section (and any other suspect joints) as well as the input connector.
Also: whenever you have a chassis out and your iron hot, start going over solder joints. I always do every joint on the neckboard and the power supply section (and any other suspect joints) as well as the input connector.
OP
OP
I've gone over everything and it looks good to me. I don't see any broken traces or solder bridges anywhere. I've double checked the solder joints on the wires under the boots that go to the focus/screen controls. Everything looks good on the flyback connections. Removed solder and re-soldered the various header pins. Checked for cracks on the neck board. Everything looks good to me.
But the image is still way to bright and massively washed out. I'll try to get a pic tonight if that helps. Any ideas??
KevinMullins
Active member
If you have another G07 around, try swapping the SCREEN/FOCUS block by itself.
OP
OP
Wish I did. All my other games are vectors and all my spare chassis are not G07's.
Also, as it's unlikely that the monitor had two completely separate problems at the time it broke, I'm thinking it's more likely that I screwed up something that I installed rather than a completely separate part randomly failing at the same time.
OP
OP
I re-soldered everything I could think to do. Looked for cracks using a magnifier. Re-checked all my work and it still looks like this. Do any of you guys who are smarter than me have any good ideas to check next?
Here's what it looks like with the brightness all the way down:
Here's what it looks like with the brightness all the way down:
Attachments
modessitt
Volunteer: Encyclopedia Submission Moderator
Is your B+ at 120?
Turn your brightness down a bit, as well as your color pots...
Turn your brightness down a bit, as well as your color pots...
OP
OP
The brightness is as low as it will go. B+ is actually slightly lower than 120. I think it was like 118 so I didn't futz with it any more.
If I turn the brightness up very much it goes all white.
modessitt
Volunteer: Encyclopedia Submission Moderator
Does it stay that bright if you unplug the video input?
OP
OP
Yes, just tried it. In fact the screen burn is so bad that it almost looks like the video input is still connected.
But it's still way bright. Looks worse in person than the pics even really get across.
modessitt
Volunteer: Encyclopedia Submission Moderator
Okay, I haven't read the entire thread, but does this have a new flyback?
Cap on the neckboard in properly? If there is a problem with it, you won't be able to turn the brightness all the way down.
You could also check R125 on the neckboard to see if it's bad...
Cap on the neckboard in properly? If there is a problem with it, you won't be able to turn the brightness all the way down.
You could also check R125 on the neckboard to see if it's bad...
OP
OP
New flyback. New Hot. New HV. New caps all around. I'll double check that cap again to be sure it's right. Would a backward cap possibly do that? I was careful but who knows.
I'll check R125 also then. Thanks for all your help so far kind sir.
You should try replacing or testing the transistor at X303 as well. I've seen 'em short before causing similar results. Worth a try anyway.
