Replacing the CRT for_an 233 revA iMac

[webolution7of9]

Does anyone know how to or can tell me how to replace a
CRT for an iMac, After lots of popping and crackling my tube has
bit the big one and I need to have it replaced.

Is this something I can do my self?
(with out a horrible shocking death?)

I found a place online to buy them but, I don’t know if I am capable of this project.
Is it simply R&R? Any help would be greatly appreciated.
thanks

[ShaolinMiddleFinger]

I once saw someone try to....KABOOM!

[webolution7of9]

OK, If I'm not standing in 2" of water?
Thanks

[LethalWolfe]

If replacing the iMac's CRT is anything like working w/a stand alone CRT I wouldn't try it unless you know exactly what you are doing. I think the "KABOOM" story refers to someone touching a capacitor, not someone standing in 2" of water.


Lethal

[topicolo]

Heh, that sounds like an interesting idea to investigate. Some guy apparently upgraded his imac to a 17" monitor after using a lot of duct tape :-). Sorry, I don't remember the link.

[Spock]

Here is instructions on how to build a 21" iMac http://www.applefritter.com/hacks/21imac/index.html

[edesignuk]

Originally posted by Spock
Here is instructions on how to build a 21" iMac http://www.applefritter.com/hacks/21imac/index.html
OMG! :eek: What a nutter, very unique though. :D

[webolution7of9]

Thank you verrrrrrrrry Coooool !!!!!
I will try this.

[Hemingray]

I've always known that you shouldn't mess with CRT's, but after doing a little online research, this post just confirmed the seriousness of the dangers you can encounter:

CRT is often called a STORAGE tube for it's ability to hold a STATIC
ELECTRIC CHARGE.

The VOLTAGE of the static charge is measured in the THOUSANDS of volts,
as opposed to the 120 volts at your wall outlet, a TYPICAL color CRT
will store 26,000 volts, virtually forever, until broken or dissipated
(correctly discharged).

TURN OFF THE MONITOR, DO *N*O*T* unplug it until AFTER discharging it...

> Essentially, you use _ONE_ hand (to decrease the chance of electrical
> current passing directly through your heart) and you use an insulated
> screwdriver or discharge tool. You run a wire from a grounded point on
> the monitor chassis to the connection under the anode cap on the CRT.

(I use a very long FLAT TIP screwdriver with a WOODEN or RUBBER handle,
keeping my hand on the back end of the grip at ALL times, (Not to be
funny but you MUST wear shoes and clothing that prevents your body from
touching ANYTHING while you work on a monitor) then slide the tip under
the rubber cap while holding the SHAFT of the screwdriver against the
metal frame of the monitor. (There MUST be GROUNDED BARE METAL TOUCHING
THE SCREWDRIVER WHILE IT TOUCHES THE ANODE!)

The Anode is the metal contact under the rubber cap at the end of a
thick RED or ORANGE wire that comes from the power supply to the top or
side of the CRT.

NEVER TOUCH THIS WIRE, OR the ANODE when power is ON, or if the CRT has
NOT been discharged! ESPECIALLY NOT with a ANYTHING METAL.

EXTREMEMLY important to note is that the unit MUST be PLUGGED IN and
TURNED OFF for this to work.

Plugged-in so that the chassis is GROUNDED at ALL TIMES during
discharge, otherwise, there is NO WHERE for the static charge to GO.

AFTER DISCHARGING THE TUBE YOU *M*U*S*T* UNPLUG THE POWER CORD.

NOW:

> After that, you remove the anode cap and set up an ongoing connection
> to ground between the CRT connection and the ground, to keep the CRT
> from recharging, which it can and does do, even without any power
> attached.

This will ONLY happen if there is current flowing in the monitor power
supply.

AFTER correctly discharging the CRT, UNPLUG the POWER CORD from the
WALL, and the ANODE will not recharge.

Welp, good luck. :D Of course, this all may be a moot point if your monitor has bit the dust, but I don't think I'd chance it...

[onemoof]

Hi, the same thing happened to my iMac Rev A with the monitor dying. It's a rampant problem that has happened to a large majority of iMac Rev A's and even later models.

Basically instead of trying to replace the monitor in your iMac you should just attach an external monitor. It only takes about 5 minutes to do this.

Simply remove the plastic bottom from your iMac,
Disconnect that monitor plug (the one with the two thumbscrews)

You now have an open monitor port on your computer which uses the old Mac monitor format.

Connect either an old Mac monitor, or any VGA compatible monitor with a Mac-VGA adapter to the port.

That's it.

Right now I'm typing on my iMac Rev A with a 17" monitor I bought on eBay for $110 including shipping.

Or just buy a new Mac, the Rev A is getting old and I'm updating when the new wave of Power Macs come out next week.

[Arcady]

I'll buy tray-loading iMacs (rev A-D) with broken/missing CRT, power supplies and analog boards. I am interested in the logic boards, CD-ROM drives, and CPU cards. Sell your broken down old imac to me!

[Dr. Distortion]

Well, I've had the same problem with my rev. B iMac, and after a little research I've found that nothing less than the flyback transformer on the analog board is broken. Before the breakdown you see and hear some sizzling noises from the iMac, and you see weird artifacts on the monitor. That's where the internal isolation of the transformer breaks down.

Now if only someone could find the supplier of these transformers I could repair my iMac. Heck, I could even put a tutorial online with pictures and all how to repair it.

Just let me know if you know a supplyer for these transformers..

-Dr. D.

P.S. yes, I know some stuff about Electro Engineering :)

[webolution7of9]

Thanks for the Info have you tried these?
http://www.flyback-transformer.com/index.htm
http://www.hitachi.co.jp/mediael/prod/fbt/fbt_e.html

http://www.happcontrols.com/index.html?http://www.happcontrols.com/monitors/4902270b.htm!

http://www.lowendmac.com/macdan/02/0102mm.html

http://www.lowendmac.com/tech/crt.shtml

http://www.computing.net/mac/wwwboard/forum/5210.html


Thanks