Fuse in Electrohome board

[dhansen]

I blew a fuse one my Electrohome monitor (soldered into the board) and am not able to find a 125volt 3amp fuse anywhere.  What happens if I put a 250volt 3 amp fuse in there?  Fire? Enternal damnation? Dogs and cats living together?

Doug

[OSCAR]

Hey Doug,

The F902 fuse?  I've noticed that in the manual, the board map calls out the F902 as a 125V fuse, but the replacement parts list it calls out for a 3A 250V fuse.  FWIW, I use 250V fuses in my GO7 without problems.

The next question, do you know why it blew the fuse?  The F902 fuse protects the power rectifier diodes, which can be shorted if the monitor is plugged in without an isolation xformer.  I've heard that a shorted degaussing coil can blow the 902 fuse, too.

[dhansen]

Thanks for the heads up Oscar!  I'm not sure why it blew the fuse.  I had everything running through an isolation transformer.  The last time I worked on this chassis is when I finally threw my arms up and bought the 8-liners chassis.  I bought three of them but one of them doesn't work correctly with this tube.   If I get it up and running with this chassis, I'm going to call it good.

Have you tried the TV tube trick with the 8-liners yet?  I bought a couple of old TV's from a local repair shop but the yolks weren't compatible.

Thanks again!

Doug

[OSCAR]

Actually, anything can really cause the rectifier diodes to short, even just powering up the monitor if they are ready to go.  Powering up without an iso xformer is just a sure way to short them out.

Check the D901-904 diodes to make sure you don't have continuity in both directions across it.  If any are shorted, you can replace them with a common FR302 rectifier diode.  Radio Shack might have them, I'm not sure.  You do want an "FR" type diode (fast recovery) to use in the rectifier circuit.  A standard rectifier diode will work for a while, but you will be replacing it again before long.


I was supposed to get a TV tube this weekend to try with my 8liners chassis, but I just didn't get to it.  I'm going to try to get it sometime this week, though.  I just need to make sure it has a 10-pin neck, I've pulled apart a couple of TV's already, and they had 8-pin necks.

[dhansen]

Cool, keep us updated!

Doug

[Brogner]

Doug, I found it kinda strange about your problem.  After reading your imformative section on the 8liners on your webpage, I went with an 8 liners for a replacement on a WG4900.  I bought a new flyback for my  G07  but something else is wrong with it. So I put the 8liners on the G07 monitor and havent had any problems with it. (well a small one, cant keep the vertical hold to stay still without some tweaking)  Meanwhile I bought another 8liner for the WG4900 and found the tube was shot....(anybody know anything about blue arcing in the picture tube?)
Both of these were high impedance 10 pin necks so I figured one would work in the other.
Brogner

[dhansen]

Cool, I'm glad someone has visited this page!  

Yeah the 8liners chassis doesn't work with this tube..I'm stumped.  That's why I was firing up the old G07 chassis.  I'll post some pics and maybe you guys could tell me what's wrong.  Btw the electrohome chassis blew up again...not the fuse this time, I've had it!!  Getting ready to buy a brand new monitor...

Thanks,
Doug