iMac G3 Slotload 350MHz No power

[Iesca]

I can now confirm that all three of the iMac G3s are alive and well, but the third's revival was a bit more dramatic than the others, although it may perhaps point to the actual problem with these things (to someone more knowledgeable than myself).

It took almost a week to start up stably. When it started turning on, at first all seemed well, but then there were snaps/pops and momentary distortions in the CRT raster. I was worried something was shorting, but I never caught it visually inside and it eventually stopped. (At this point it was not reliably staying on.) However, the display would then begin to sink and distort on the screen, with horizontal worms across the whole display, lasting generally until the machine was shut off again. This too has disappeared, and everything appears to now be completely stable. I backed up the HDD, installed the original system, and updated through 9.2.2.

Before I update the firmware to 4.1.9f, is there reason to try and preserve the factory boot ROM? It's version 1.2f2, though I would have no idea how to do this.

Edited February 4 by Iesca

[Iesca]

Another update: the new speaker drivers I ordered on ebay arrived recently and I was able to install them successfully! (When installing any new drivers, make sure that the red wire is on the left side for each one while you face the speaker assemblies as they would be installed in the iMac, at least for the Graphite iMac G3/400 DV SE).

My only comment is that they are very loud, I had to turn the speakers down individually all the way from within the Sound control panel, otherwise, even with the master volume set to near minimum, they were quite blasting. Perhaps 4Ω is too low an impedance?

Edited February 16 by Iesca

[CC_333]

On 2/16/2021 at 2:38 PM, Iesca said:

My only comment is that they are very loud, I had to turn the speakers down individually all the way from within the Sound control panel, otherwise, even with the master volume set to near minimum, they were quite blasting. Perhaps 4Ω is too low an impedance?

Maybe so.  I'm not super well-versed in the subject of loudspeakers, but maybe one can add a resistor of the appropriate wattage to increase the impedance to 8Ω?

 

c