It is obviously there is no problem with the power supply. But for put the machine back on track you will need an original HDD (121K30550 new or from scrap) because the machine software reside on that HDD
On the other hand, for connecting the PWS to the machine you need a serial cable and a Null Modem.
DOWNLOAD MODE represent the procedure for downloading software to machine, but you need the machine software CD. Also for downloading the software you need the serial cable, the Null Modem and a crossover cable.
Anyway, the machine is so old, it is EOS.
I got a Xerox 3535 from a printshop, not working. The owner reported the Xerox tech had said it needed a power supply. He promised to come fix it with a part from another machine, but never did. The owner reported tension between the tech and him. Digging in, I found it didn't boot up, and gave a HDD error message.
I looked inside - no hard drive. I bought a 20Gb hard drive that matched specs. Upon installing, it gave an 116-330 at startup. The machine would only flash to the first of the five circles before displaying the fault code and stopping. I tried 4-STOP-POWERSAVE but it didn't seem to work. Instead it brought me to a screen that said "DOWNLOAD MODE". I bought an old laptop with Windows XP, a new serial cable, and installed my PWS software. I connected the cable and ran the PWS 3535 Diagnostic Tool. It won't connect to the machine, though I try and try.
Can anyone tell me what "DOWNLOAD MODE" is?
Or, what to do when PWS won't connect?
I'm wondering if it is truly a power supply board. I'm also wondering if that Xerox tech actually took the HDD out and gave it to someone else, and if he might have taken chips also. I'm not sure how to debug these things without PWS.