discharging monitor questions (wells Gardner)

[cack01]

I read all the guides I can find, and I've come up with questions I'm hoping you guys can answer.

1. I can't decide if I should use the monitors metal frame, or my apartment's ground. I'm alittle afraid to use the apartment's b/c I don't want to blow anything I do not own.

2. If I use the monitor's frame, should I unhook the monitor's PCB from everything? I read an article that said grounding to the frame might cause all the energy to go back into the PCB. I figure if I unhook everthing but the anode I can prevent that. But I'm afraid with the ground from the PSU not being connected I will have problems.

3. Should I go through and discharge every cap on the PCB before I work on it. (redoing the caps.)

thanks
cack01

[SirPeale]

1. I can't decide if I should use the monitors metal frame, or my apartment's ground. I'm alittle afraid to use the apartment's b/c I don't want to blow anything I do not own.

Use the metal frame.

2. If I use the monitor's frame, should I unhook the monitor's PCB from everything? I read an article that said grounding to the frame might cause all the energy to go back into the PCB. I figure if I unhook everthing but the anode I can prevent that. But I'm afraid with the ground from the PSU not being connected I will have problems.

No, leave the PCB intact.

3. Should I go through and discharge every cap on the PCB before I work on it. (redoing the caps.)

No.  The dangerous voltage isn't in those caps.

Ken Layton and MonitorGuru have posted several helpful topics regarding this.  Check out posts by them for more informative answers.

[cack01]

thanks.  (but now more questions   )

I got the anode off.  But didn't hear any pops or anything.  But the cab has been unplugged for a week so maybe it just didn't have a charge anymore.  I have a WG K7000 series.

I'm trying to disconnect all the wiring so I can take the PCB out of the cab.  I ran into problems on two sets of wires though.  I was wondering if its possible to cuts the wires  and install molex conectors.  Both sets are going to the neck PCB.  One wire is coming from the flyback and going to the very base of the tube.  (electron gun ?)

The second set is coming from the main PCB and has 4 wires on it.  3 blue one white.    There are actually two groups of wires like this but the other wires identical to these have a quick release connector built in the board.  

So if I cut these wires and install molex or quick disconnects will I have signal loss or any issues I should be aware of?

Thanks
cack01

[Ken Layton]

You don't cut any of those wires. The neck board comes out with the main board. There is a black ground wire that goes from the neck board to the spring and strap wrapped around the dark area on the rear of the picture tube that you can cut to remove the neck board (wire nut it back together later).

[cack01]

LOL thanks.

My neck board has some glue on it?  RTV glue?  I'm guessing I just gently tear it off.  Once I put the board back on, what should I use keep the neck board secure.  Or even better where is a good place for RTV glue.  Home depot, ACE??

thanks

[pcdoctor]

I have never discharged a monitor but here is some info that I found.
I'm not an Apple user but just found these to be real helpful for my boyfriend when in installing a tv in my PS2 cabinet.

http://www.biwa.ne.jp/~shamada/fullmac/repairEng.html#DischargeCRT

http://www.wileytradegroup.com/imac_repair/displaydischarge.pdf

I bought a safeaback discharger from Bob Roberts a few years back.
http://www.dameon.net/BBBB/sb.html

[JoeB]

LOL thanks.

My neck board has some glue on it?  RTV glue?  I'm guessing I just gently tear it off.  Once I put the board back on, what should I use keep the neck board secure.  Or even better where is a good place for RTV glue.  Home depot, ACE??

thanks

When I took the PCB board out of my WG7000 series monitor, I noticed that those wires going to the neck board were already cut by the previous owner and he used one of those electrical twist caps to tie it together. (the same ones you use in electrical outlets/overhead lights).  And if they're good for 110V/220V high current homes, I'm sure they'll be find for the your monitor.

It's always easier to replace that wire/patch it up than replace the entire CRT because of a broken neck.

That was my philosophy anyways.

Good luck!  and don't forget to label everything so you'll know how to put it back when you're done.  

[Ken Layton]

As monitors are shipped from the factories, the manufacturers put a small dob of silicone glue on the tube socket and tube. The reason they did this was to secure the neckboard during shipment. Take a small xacto knife and carefully cut thru the glue. You do not replace the glue.

Never cut the wires (exception is the black ground wire going to the monitor grounding strap) on the neck board. That black wire from the flyback to the picture tube socket is the focus voltage wire which can run up to 4,000 volts! The other single wire from the flyback which is red or gray with a single pin connector is the "screen" voltage (up to 600 volts) to the tube. Remember to "leave servicing to qualified personnel" or you could be electrocuted.

[cack01]

Thanks for the help.  Replacing all the caps went much smoother than usual.  Probably b/c I'm used to replacing caps on motherboards with tiny traces everywhere.

I was even able to find the problem caps.  #'s 56,57,50, and 40 had all melted to the board.  I just could not see it without the PCB right in front of me.  I've seen many bad caps, but none that bursted like this, and in all the same manner.