Electrohome G07 Mystery Please help

[wildman9690]

OK heres the deal I have a Big problem with a g07 you guys might be able to help me with.  First off it is dead,  For awhile it would work, then for awhile then go blank,  then finally nothing.  I took it apart to find that fuse f901 was blown.  I replaced the fuse turn it on and nothing.  I took it back out checked the fuse and still good.  There is for a fact no High Voltage, No Neck Glow.  Voltages on the big white resistor read about 160v  The resistor checks out fine also. The x01 reads 160v also.  I removed the x701 x-ray protection to see if it worked, and still nothing.  I then checked x501 it is also good.  The only thing left is ic501 which i have taken out but havent got a replacement yet.  before i get a new ic501 is that what may be wrong?  Also i have done a visual check and a continuity check for cracks on the board there where none.  Also re soldered some suspected joints.  Am I on the right track? any help would be appreciated.  Thanks, Andy

[steveh]

i have the same monitor i am trying to work on. i dont know if you have the flowchart for it or not but it was posted here in my thread.  along with some other tips.

http://forum.arcadecontrols.com/index.php?topic=61048.0

i am not as far as you are tho (no time to work on it

[wildman9690]

I have read that thread and it helped a little bit and i have gone through the flow chart,  Just stuck at ti IC501 and dont want to buy one if thats not the problem and if anyone has actually had the same problem at the IC was the problem.  Thanks everyone

[Grauwulf]

Have you done a cap kit yet? C511 can cause the monitor to not turn on. Have you also checked the voltage at both ends of the resistor?

[Ken Layton]

Check out this:

www.homearcade.org/BBBB/g07note.html

You have installed a full capkit now haven't you? If you got your kit from Zanen Electronics then you would have also gotten a resistor with that kit (resistor R908, which is part of the power supply section).

If the flyback on your monitor is original, have you replaced it yet?

If the width coil on your monitor is an original, have you replaced it yet?

Have you checked/replaced the horizontal output transistor and the B+ voltage regulator transistor?

[wildman9690]

well i havent done a cap kit yet because going through randy fromm flow chart so far doesnt say that c511 is my problem yet  the output of the white resistor is 160v and the other side is close to 150v and the resistor checks out with the correct specs.  Thanks

[wildman9690]

ohh and a cap kit has been done on this board before and the flyback has been changed before also i didnt do it i could just tell by the parts and the soldering on the board.

[Grauwulf]

Doesn't mean that it doesn't need a cap kit again. I would try changing the cap first and then change the voltage regulator.

[SirPeale]

Doesn't mean that it doesn't need a cap kit again. I would try changing the cap first and then change the voltage regulator.

Agreed.  Just because a cap kit has been done in the monitors life doesn't mean that it's been done *recently*.  Heck, on a nearly 30 year old monitor, it could have been done ten years ago.

[wildman9690]

Ok a quick question for everyone who has done these before,  will a cap kit take care of the 160v reading that im getting on the big white resistor?  what i have been reading is that i have a horizontal deflection problem.  Is that have anything to do with the cap kit?  I will do that if bad caps cause the problems i am having.  Will a bad c511 give a 160v reading on the resistor and the regulator case and the x01 case? thats what im getting.  also its not turning on with x701 removed.  Thanks, Andy

[Grauwulf]

Well if it is not running even with X701 removed then you should be resoldering all the flyback connections first and give the bottom of the chassis a good visual inspection.

[wildman9690]

Yup I have done that lookded over very good checked solder joints resoldered many of them even used a meter to check for cracks across the board.  It still looks good!

[steveh]

does the board have cracks in it?!?!

[Ken Layton]

Have all the power supply section components been tested/checked?

[wildman9690]

There are no cracks,  And where are the power supply components located at.
Thanks, Andy

[SirPeale]

And where are the power supply components located at.

See where the power comes in?  Start there.