Imagewriter II Repair

[CatCakes]

Hi there,

So I received an Imagewriter II in the mail, it had been banged up somewhat and the bottom portion, the metal bottom which holds the board and the power supply had broken off a bit. I figured this was from the weight, and really just a cosmetic issue, since it would be concealed most of the time.

Sure enough, it won't start up. I've opened it up, checked the fuses, checked all the connections (assuming something was bumped out of a socket) and nothing. Everything looks good. I disassembled all the way to the just the power going to the power supply (from the right leg) and I get the same thing on all tries.

Here's the weird part. What I get is a slight bump from the power supply. When I push in the power button just a bit, the power supply will "zonk" a tiny bit, both in sound and movement. It has done this with everything put together (as I received the printer) and with nothing attached to anything except the power to the power supply.

What do you guys think? A dead power supply? and if that's the case, would it seem like a replacement might fix it? I doubt that the power supply used is a general item that can be picked up at an electronics store (like a PC one) but I'm not well versed enough in this stuff to make that call.

I've checked some apple repair guides, which were disheartening, they usually said things like: replace the driver pcb or cpu pcb, etc.

Cheers.

 

[trag]

Identify the supply lines leaving the power supply. E.g. in a modern computer you'd look for 5v, 12V and 3.3V. I don't know what the IWII has. Anyway, identify those lines and then check their resistance to ground. Perhaps there's a short somewhere from the broken metal bottom plate?

Other than that, try Larry Pina's book on Mac Printers. Ah, here we go:

http://www.amazon.com/Macintosh-Printer-Secrets-Hayden-Library/dp/0672484633/ref=sr_1_6?ie=UTF8&s=books&qid=1210959463&sr=1-6

"Macintosh Printer Secrets".

There are two main circuit boards in the IWII and having a spare of each on hand is a nice luxury which is challenging to achieve these days. But you might try Ebay or the LEM Swaplist or the Trading Post here. There may be someone who wants to dispose of an old IWII who is willing to part it out.

Oh, on ebay there's a seller who goes by the name olde Mac Milt. He may have an IWII power board.

 

[tomlee59]

I would also check for the *absence* of a load. Switching power supplies generally require a minimum current draw in order to work properly. If a trace got cracked, the switcher would be operating into an open circuit. If the power supply doesn't have a built-in load resistor, then what happens is that the initial turn-on causes a large voltage overshoot, and then a protection circuit kicks in to prevent damage.

You can connect a load resistor from the output to ground (say, enough to pull a few hundred milliamps) and see if that makes the power supply happy. If so, then your next step is to locate the open circuit.

 

[CatCakes]

Thanks for the replies!

 

[pfuentes69]

Hello.
I know this is a very old thread, but posting here as I have exactly the same issue.
My IW2 was working and while printing it made a nasty sound and then it died. When trying to powering on I have the same faint "zonk" and slight movement, but LEDs don't light up.
For to try something, I recapped the power supply, but I didn't get any change.
Any hint of what could be the issue?