In 13 years of reading/posting in these Forums, I've never come across a suggestion (or made one) to remove the ROM chips, as a means of troubleshooting startup problems. A new battery should have cured the problem, if not a PRAM zapping. I doubt you'd find anyone with the hardware needed to program a set of ROM chips. I'd suggest checking eBay for an LCIII motherboard, because I think it would be unlikely to find an auction for the ROM chips alone. I own an LC I and LC III. A couple of years after buying the LC III, I bought a spare motherboard for it at eBay, in the event of failure.
I'm still trying to save this Macintosh. I have replaced the ROMS and the PRAM battery but still does not work.
The computer powers on and it does a small sound from the speaker but no bong. The HD starts up and the fans work. The screen remains black, no startup bong/chime.
I have tried resetting the PRAM and leaving it on all night. I tried switching on/off quickly. Nothing.
I tested the voltages from the PSU. The 12V line gives 11.8 and the 5V gives like 4.9. That should be ok no ?
I tried disconnecting the floppy drive and the HD and i have tried cleaning the motherboard with a proper PCB cleaner spray.
Is the Logic board trash ?
"The ROMS got really hot to touch"
And you say other chips are getting hot too. If you're *sure* the ROMs (and everything else, e.g. RAM) are now inserted properly and that you have a good battery installed, then the motherboard may be fried. But to be 100% sure, you need a second LC III so you can swap parts, e.g. ROMs, power supplies, etc., to do further testing. It could just be the ROMs.