Gregory's Server|
9 comments
 the circuit is similar to the "typical application circuit" and it looks like there are two small electrolytic capacitors on the UC3842 VCC rail that have gone super leaky, preventing it from bootstrapping and powering up. it was a simple enough fix. the yellow screen means it is trying to load the Kickstart off of a special drive partition. oh that's not good, it blinks red 8 times. this means the drive failed the SCSI mode sense command for some reason. weird. @tubetime Is that something special added by the controller interface? Or is the onboard boot room able to look for kickstart other than the floppy disk? @ChartreuseK the onboard (non kickstart) ROM looks at F00000 and finds the controller ROM, which then takes over the boot process. i think this was originally for supporting game cartridges @tubetime Ah okay, didn't know that was a thing it did. Certainly a nice feature to not need the kickstart disk to boot a hard disk  @tubetime I've run into this in audio amplifiers too. They have a bootstrap pin which is connected to a RC network off a supply voltage - the cap charges up slowly once the power comes on and eventually lets the amp come out of inhibit. It's a power up thump avoidance thingy. And yeah, when the cap fails short, the amp plays dead |
the controller is the UC3842. hmm.