EX5 diagnostics- Wave ROM NG

[Rocinante01]

Recently purchased an EX5, and it was immediately clear there was a problem with it. The first initial sounds were fine, but it soon became apparent there was something wrong with either the output or it’s internal data was somehow corrupt. The evidence was in hissing, distorted sounds.
After changing the battery (which was dead), I did a factory set restore, and this did not remedy the problem.
I performed a full deep cleaning of the unit, cleaning all button contacts, etc, and then ran a diagnostic.
It became apparent that there was something wrong with the TG and OS chip IC’s, so I upgraded them to their most recent IC’s. Upon removing the old IC’s it looked as though I found the problem, as whoever repaired this synth previously, they bent three prongs on one of the IC chips, so I was sure I had solved the problem.
Unfortunately, this did not resolve the problem, and now I see that the Wave ROM error is in IC54.
Looking at the schematic, IC54 is not on the chip side of the board, but is listed on the trace side of the main board, underneath the IC52 chip location, right next to the Flash RAM ports.
How do I then go about replacing the IC54 chip? And would Yamaha even carry the part? (I live just a few minutes away from the Buena Park location so I can source directly from them).
I’d really like to get this synth back to functioning properly.
Can anyone lend some insight here?

063D4BAC-9762-4D44-92BD-77452CCCAF4F.jpeg

[jima]

Hi, welcome to Yamaha Musicians.
Are you a fan of Don Quixote or The Expanse? Either way, cracking good tales, the latter one of my favourites! Unfortunately, not such a good tale for your EX5. IC54 is one of four 32M chips which together comprise the 'Wave ROM'. It is a surface mount component on the main DM circuit board. Even if you could get a component (very low probability) it would be a complex task for an experienced surface mount tech to replace. You have, I think, two options from here - try to source a replacement DM board either from Yamaha or a donor synth (there are some shipping casualties out there should you be lucky enough to spot one) or a Yamaha specialist (e.g. there is one good one in Europe) but this may be cost prohibitive, alternatively return the synth as it clearly had a major fault when sold if that is an option.

Whichever route you go, good fortune be with you and please let us know the outcome, either way.

[Rocinante01]

Unfortunately, I’d already made my piece with the unit from the seller, and he gave me a refund to cover the cost and install of the OS and TG chips, which I felt at the time was the resolution.
I still have a fully functioning EX7, so I can wait it out till I can find a new main board, or I’ll resort to selling it in parts.
I’m ultimately looking for an EX5r, so this synth can remain a project for now. A TG board will come up eventually.

[Rocinante01]

Oh, also, to answer your question.
Long time Rush fan. Which by extension, the reference goes directly to Don Quixote.

[jima]

OK, well, best of luck with it. BTW I would need to double check the schematics but ISTR the DM board is commmon to the EX5 and the EX7 bar a link or two so that may open up some options.

[Rocinante01]

I’ve actually decided to wait around to find a salvageable EX5 that I can take the board out and sell the rest for parts. In the meantime, I did locate an EX5r that is what I want in my rig to begin with. The ex5 will remain a project for now.

[sergiommms]

So... after all this time... was the problem solved or not?
I am also experiencing faults at:
IC51, IC 53 ("Wave ROM 1 32M" and "Wave ROM 3 32M"), also marked as "LL" and "LU"
and also at:
IC 55, IC 56 (both "DRAM 4 M"), also marked as "L" and "H".

They all sit on PCB "DM", with Yamaha part number XS758 as far as I can tell (it´s the mainboard).

[jima]

Hi, welcome to Yamaha Musicians. The DM board is the main board. The chips you mention are all surface mount devices on a data bus driven by the tone generators. Even if you could source replacements (unlikely for the Wave ROM's which will be proprietary) the cost and complexity of the job will likely make it a non-starter. Make sure you test without any Flash or RAM installed in the sockets and if the faults are still present the only likely viable option these days is a donor board from a scrapped EX5.