Power Mac AIO G3s

[Mike Richardson]

I have over 20 AIO G3s, maybe 25. At least 5 arc, probably more. By arc I mean that every several seconds the screen pops violently and you can hear an arc going on somewhere in the system.

My first question is: Is it the flyback? And I think the answer is yes, they used some sort of defective or cheap flyback on the G3 AIO.

The second question: Is there any cheap source for flybacks? $10 or less each shipped?

I know all about the high voltages and all of that. I've labeled all of the arcing G3s and they have been turned off for months. The energy should have dissipated by now. Additionally my friend's dad is an engineer and has appropriate tools.

If I can't get cheap flybacks, should I go ahead and strip out these G3s? The tubes are good, so it really seems like a waste of a tube. So far I haven't seen one with a bad tube, just a bad flyback/analog board. I could always keep one or two around for the tubes if I ever do happen to come across one with a bad tube but a good flyback/analog. I have not turned on all of my G3s so I don't know.

I need to clear out space. So I either need to fix up arcing G3s and sell them or break them down for parts.

 

[redrouteone]

I had a B&W 17" Apple CRT display that had a failing flyback.

I bought a new flyback off eBay for about $20 and it took me about an afternoon to install it. Of course there are all of the normal electrocution warnings, but you need to be fairly proficient at soldering also. If you get the contact took you can melt the insulation on the wires in the flyback. The other issue is that you have to re-calibrate the display after replacing the flyback. I believe on the G3 AIO it can all be done from the front panel. Though I have repaired other monitors that require making adjustments inside of the monitor.

Given the vale of G3s I would suggest parting them out. I've never taken apart a G3 AIO but I would be surprised if there is less than 2-3 hours labor involved in the repair.

 

[tomlee59]

I've never opened up an AIO, so I am unsure of its specific anatomy. But based on my experience with many color TVs and monitors, here are some hints:

First, identify where the arcing is occurring. Is it from the body of the flyback to some nearby piece of metal? Is it from the anode lead (esp. near the cup)? Is there a voltage doubler/tripler module (sometimes identifiable by a focus control pot mounted on/within it) that's doing the arcing (again, often to a nearby piece of metal)?

1) Arcing from the anode button is often facilitated by accumulated dust around the button. Simply brush it off -- be gentle. An ordinary paint brush works well. Be careful not to abrade away the Aquadag coating -- it forms one plate of a high-voltage capacitor used by the CRT circuitry.

2) Arcing from the HV lead itself is a sign that the insulation has broken down. The only reliable fix is replacement. In a pinch, you can sometimes get by with a few layers of electrical tape, supplemented by dressing the lead away from the chassis and other metal parts.

3) If there's a voltage multiplier module, it will often be the point of failure (the highest voltages will be there). I've lost count of the number of color TVs -- particularly projection TVs -- I've encountered with bad multipliers. The arcing usually takes place through the body of the module to a part of the chassis to which it's attached. If the damage is slight, a perfectly fine fix is to scrape (carefully) the obviously toasted parts of the body, and then to fill in the hole with epoxy. Let it dry for at least a full day (don't be impatient, or you will be sorry). The first TV I fixed this way was still working 20 years later, when it was finally decommissioned because its owner just got tired of it.

4) If the body of the flyback is arcing to some nearby metal, you might be able to salvage it using the same basic method as in 3). Just don't scrape any wiring -- just clean up the surface, then slather in some epoxy. If the flyback was only arcing intermittently, this fix may work well over a long term.

 

[Mike Richardson]

I had a B&W 17" Apple CRT display that had a failing flyback.
I bought a new flyback off eBay for about $20 and it took me about an afternoon to install it. Of course there are all of the normal electrocution warnings, but you need to be fairly proficient at soldering also. If you get the contact took you can melt the insulation on the wires in the flyback. The other issue is that you have to re-calibrate the display after replacing the flyback. I believe on the G3 AIO it can all be done from the front panel. Though I have repaired other monitors that require making adjustments inside of the monitor.

Given the vale of G3s I would suggest parting them out. I've never taken apart a G3 AIO but I would be surprised if there is less than 2-3 hours labor involved in the repair.

I have several of those B&W Trinitron displays as well. About 40% of them have a problem where the entire screen image kind of shrinks and then re-expands. You can hear some sort of pop, maybe an arc. This will occur randomly/intermittently. Is that the same problem you had - making it the flyback? It might be worthwhile to fix the displays in my case, because they are complimentary to the G4 systems that I sell. I could give then a crappy old Dell display but the buyers seem to like when it all matches up.

 

[redrouteone]

Yes that is exactly the problem I had. From what I understand it is a common problem with those displays.

 

[flyingtoasteroven]

Hey I had a B&W 17" with the exact same problem a couple years ago. I tossed it, figuring it was unfixable. It was by me. But I guess not by everyone. Too bad, I guess.

 

[Bunsen]

B&W 17" Apple CRT / new flyback off eBay for about $20

Is this a model with a known failure rate for flybacks? And if so, was that the exact same, badly designed original flyback that you replaced it with?

 

[redrouteone]

Is this a model with a known failure rate for flybacks? And if so, was that the exact same, badly designed original flyback that you replaced it with?

Yep flyback failure is very common on those displays. The new flyback I used was from a different manufacture. The original was an LG. The new one was the Chinese special of the week. I don't know if it was any better but it could not have been worse.

 

[MrMacintosh]

For a long time Apple would replace or repair those failed B&W CRTs. A 2-3 years back a friend of mine called about it, as he had read something on Apple Discussions or in the Knowledge Base. He mentioned that to the support rep and Apple shipped him a box to send the display back. He had a working one back next week.

 

[WorkgroupServer]

Mike,

I have completely dismantled a G3 AIO before. It took me a couple of hours, and is kind of a pain, but it can be done. The nice part is the analog board slides out after you get the CRT parts exposed. I was able to replace my analog board and everything has been running smoothly ever since. Still, I'm not sure where you can find cheap replacement flyback transformers....

 

[Mike Richardson]

I just took apart one of the G3 AIOs that was arcing particularly violently. I blew everything out with canned air and jiggled the analog board a little bit and now, so far at least, it doesn't arc any more. I have decided to cancel parting them out for now.

 

[Mike Richardson]

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[Christopher]

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hahaha, what?