Hey,
is there any way to flash the EEPROM on the JP-8000 directly on the chip itself? Anyone tried it before?
(context: I ruined my JP-8k by re-capping the main board, now only the screen turns on, half of the display is full, the other half is empty, no LEDs are working and no sound coming out. It worked before. The connections are ok. The caps are working. No damage on the main board. I believe the OS won’t boot so I’m researching how to flash the ROM.)
Thanks in advance for any help.
I have the same exact problem. Major audio issued so I recapped everything on the main board and it worked fine except for memory damaged error even though I replaced the battery and reset it the error still came up so I ignored it as I could still save patches. I got the ribbon controller calibrated but for some reason the pitch bend was unresponsive, even in the great menu.
I was on firmware 1.1 and I saw that 1.5 fixed some pitch bend issues so before taking it apart again to see if there was a hardware issue I decided to flash the new firmware, big mistake. All the checksums came up fine for all 8 files (then hitting rec after each file) when flashing then after 8 (it still says play next file) so I just turned it off then back on then get top of the LCD screen lit up all the way across them bottom blank all the way across and the synth itself completely unresponsive.
I’m suspecting something happened on the main board when I was soldering that affected the battery hookup but I I couldn’t see anything. If this was the case attempting to flash the eprom would probably just erase it so now I have a JP8000 with no brain.
I can still use the key combo to get back in to the firmware flash menu but all the other key combos don’t work.
I’m thinking of putting it on eBay for parts.
The ribbon cable that goes from the screen to the mainboard is kind of flaky. Double check that it’s plugged in properly, not broken or shorting to the metal foil shield. I had something similar happen to me and it was just that connection.
As far as my JP being bricked I flashed the 1.05 rom from a different computer files 1-8 pressing REC after each file then after #8 it said play next file so without turning off the machine I flashed files 1-8 again then turned it off then back on, it worked!! Went thru the calibration menu and got the ribbon controller calibrated but, heh, pitch bend/mod still no signal. I’ll take it apart again and check the connection like you recommended.
Well, silly me, you were right. I pulled out the main board and there was the cable plug for the pb lying there underneath unplugged. I plugged it back in and now the synth is 100%