Hello, just tried to upgrade my working EX5R from the original eproms to the latest available versions but accidentally installed them backwards. (Unfortunately, Yamaha did not “idiot proof” the sockets by making it so the chips could only be installed the right way, and sure enough, this idiot did it wrong!) I powered the unit up, but just got a green screen on the display. When I realized my mistake, I removed the chips and reinstalled them the correct way, and for a moment, I thought all was well because it ran through the normal boot up with the “I am ready” screen…but then the unit just froze. I shut it off and turned it back on and only got a blank display. It lights up, but says nothing. Now the synth will not boot up at all. We even tried reinstalling the original chips but to no avail. Can anyone help? I feel like I may have just made a thousand dollar blunder.
Might be worth checking the power rails generally to make sure they’re all OK and especially the pins on the EEPROM. With any luck you might have just fried a power rail…
Also look for any heated components that might have failed.
Thanks for the suggestion. Right now the unit is in the hands of my Yamaha tech and I think he has already tried that, but I will discuss with him again. He says you can’t even get a service manual for these–they exist for the EX5 (I have one) but not for the EX5R, which he says is completely different. (I guess like the rack versions of Motif were different from the keyboard versions.) He is checking with his connections to get a scanned version of the service manual. Yamaha doesn’t want to know at this point. Their view on it is essentially, “hey, the thing is 27 years old…how about just buying a new Montage M?”
I am thinking the problem is not in the power supply as the unit does turn on and the display lights up. I am not a tech, but that would indicate to me that the power supply is working OK. The problem is that the display just shows a blank screen. On the couple of occasions where it appeared to boot up normally, it would then freeze up after two or three minutes and none of the controls would operate. I would shut it off to hopefully reset it and then get nothing but the blank screen. Would you or anyone on the forum have access to a service manual for an EX5R? My tech says he can’t trace the problem without having a service manual for a “map.”
There’s usually several power rails on most electronic stuff.
Some may be missing because the reverse chip installation drew too much power.
I’ve had a look for the service manual, but can only see the EX5 which seems no good as the EX5R is different. I can only think you ask one of the websites that sells the service manuals.
Sometime when you do that, the battery backup ram get corrupted. Take the battery out and short the terminals. The place battery back in.
The other issue is you toasted the eeproms. Not hard to do if you reversed them. I killed an eeprom placing it backwards into its socket. Didnt kill the motherboard though.
Eeproms are quite sensitive in that they dont like power where it shouldnt be. Obviously you can place the old ones back and see if that works.
Thanks, I will definitely try the battery suggestion. We have already tried replacing the chips with the original working ones, but the unit will still not boot up. No luck yet locating a service manual for the EX5R…everyone seems to have the one for the keyboard but no one has the one for the rack. Hopefully someone reading here might provide a lead.
Thanks for looking. I’ve tried all the usual manual website sources I’ve been able to find so far–my results have been the same as yours–the EX5 service manual easy to find–the EX5R one doesn’t exist, as far as they are concerned. But of course, we know it does, so someone somewhere must have one.
Thanks to a friend from Australia, I’ve secured a service manual for the EX5R. I passed it along to my Yamaha tech but the manual seemed to have provided him with just enough information to determine that because of the way the chips are wired directly into the CPU that has 160 pins on it, he can not properly diagnose the problem without far more sophisticated equipment than he has available. He said he needs to talk with someone more experienced with these units. So…at this point it looks like I will be breaking up this EX5R for parts since a new DM board for it is likely unobtainable. If anyone reading this can offer a better solution, I’m open to it. Thanks for any help you can render. Wanna buy an EX5R…cheep?
Have you asked your tech if he checked address and data lines with a scope? It could give an indication on where the problem may be - check the lines with ROM’s in and out.
Hey, thanks for the suggestion. I will mention it to him, but I have the unit back now as I did not want to run up too much money in diagnostic charges. I will see what he says. I’ve already bought another EX5R anyway…but I would certainly still like to save this one if it can be saved.
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Hey, thanks to everyone who tried to help with my EX5R, especially Werner from “down undah” who supplied a very rare service manual for this unit. After thorough consultation with my Yamaha tech, I decided just to move on from it and consider it an (expensive) lesson learned. I pulled the SCSI board and the SIMMs from it and am selling them online. I listed the rest of it as a unit with the intention of parting it out if it didn’t sell and someone bought it for $225, so…all things considered, not as much of a hit as I thought I was going to take. He’s pretty sure the DM board is fried as well, but if he can get it up and running again, more power to him. And if not, he has box of still working parts, at least, that might prove useful to someone else down the line.