512k not booting completely

[mori512k]

Have a 512k that was giving error code indicating bad ram.

After changing the ram, get a nice bong and question mark. When floppy is inserted, the welcome to macintosh screen shows, but then the screen flickers and the floppy drive chugs like it can't finish reading.

It does the same thing when a known working external drive is used to try and boot.

Tried another boot disk and the same thing happens. Replaced the Bourns filter for the floppy drive and still no fix.

Any suggestions?

 

[techknight]

analog board needs recapped

 

[mori512k]

Ok. Replaced C1 already. Time to replace more.

 

[uniserver]

Yes get to those 1000uf ones, Would be nice if you could watch the 5v rail while that is going on. Also. Sure the disk is good? Try another disk just for giggles , I get screwy disks all the time, Also a good diagnostic would be to buy a floppy emu. Then you at least know you are sending proper data to the machine. Floppy disks and drives aside.

 

[uniserver]

Maybe turn the screen brightness way down and see if it progresses , Just for giggles.

 

[mori512k]

Guess what, turns out the floppies were flaky. For some reason the boot floppies made on the plus didn't like them. Tested them on my other 512k and got the same results. Reformatted on the 512k and the new one accepted it, however, only via the external drive, but at least the Mac does work. Uni, I put the refurbed analog board I got from you in since its a known working one.

I ran out of caps on the original AB, so that will have to wait until the parts come in.

The internal floppy drive is acting up. It continuously runs like it's trying to read a disk, so that will have to be pulled again for analysis.