Alesis Fusion PSU Repair and Cooling Sys

[marcelozaz]

first of all I thank to Jesse greatly for his help and time without which this information had not come to you.

Hello everyone, if any of you have a problem with the Fusion PSU and the heat generated by it maybe this information will be helpful to you.

A few weeks ago my Fusion shut down and/or restarted after a few hours of use. The front panel was hot, so I asked a friend of mine who is a technician to check the PSU. He found that the PSU temperature runs very hot, this is not good.
We tested the Fusion power supply and found that the heatsinks were so hot they could not be touched.

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Picture sizes have been reduced so the PDF doc could be uploaded to the forum
Marcelo - Alesis Fusion PSU Repair and Cool....pdf (844.16 KB)


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[Jesse]

Thanks for sharing this important information

Note: The two capacitors' Marcello replaced were the problem in his case, there could be other problems with the Fusion PSU. The more information we gather from other people who have repaired their Fusion PSU the better understanding we will have of the power supplies weak area's, what to look for and how to repair or redesign it.

[Jesse]

Anyone else have any information on Fusion PSU repair.

If you have an old Fusion PSU that you have replaced and you don't need it please send it to me so I can look it over and try to find a new source for a compaitable replacement.

Thanks ... Jesse

[tekuk]

Hi Marcelo,
Thanks for a great doc.
Could you give more information about the way you replaced the capacitors?
From the pictures, they seemed to be hidden under the heat sink...
How difficult a job was it?

Thanks

Laurent

[tekuk]

Right, a bit more info.
I played with my band yesterday and my Fusion worked absolutely fine for the 2 hours rehearsal.
In fact, after chatting with the guitar player (who happens to know a little bit about electronics), we came to the conclusion that my Fusion was rebooting constantly in one rehearsal room but not the other!
Each time we played in the same room than yesterday, the Fusion was fine. Also, when the Fusion reboots, it usually does it straight away, not after a few hours, unlike Marcello's problem which means the problem is not necessariloy related to Heat.
I mentioned the Capacitor "upgrade" and he said that when capacitor overheats they usually blow.
He also mentioned that some capacitors might be there to smooth out the incoming current when fluctuations are detected, and that could be the problem but that it's difficult to know which ones are doing what.
So bottom line, it seems to me that there are 2 potential symptoms:
1. Overheat problem AFTER A FEW HOURS
2. Current fluctuation problems which trigger a reboot.

Hope this helps

Laurent

[Jesse]

Might be good to use a battery backup UPS.

[tekuk]

Yes that's an option and I think i've seen in previous posts that it was a workaround suggested by Alesis.
It is just a workaround though...
A proper fix would be better. The trick is to find which Capacitors play that role and whether they can be upgraded.

[marcelozaz]

Hello tekuk, in my case I discovered which of the capacitor were bad because I tested with an oscilloscope and had too much ripple, it is quite difficult to replace these capacitors but not impossible, is a little bit of patience and pulse. anyway it is advisable to replace the capacitors that have ripple because this will increase over time and may produce undesirable results ...

regards

[tekuk]

Thanks Marcello,
yes the capacitors seem to be placed under th heatsink.
Was it difficult to get to the capacitors?
Thanks
Laurent

[tekuk]

oh and just got an email from Alesis.
Apparently the power board can no longer be obtained from any location in the world... :-(

[marcelozaz]

Hi Laurent chek this link www.instrumentalparts.com/alfu6hdsppa6.html

[riffbeeper]

If what alesis's E-mail to tukuk says is true, then they should be able to give us (The loyal Fusion community) diagrams, codes, detailed pictures, schematics. etc. I

would think!!!!

Iff

[parametric]

In an ideal world, I wholeheartedly agree.

I suspect that while there is still money to be made in servicing/such spares as they DO have - then this won't be considered. Sadly that DOES make commercial sense - to them at least.

If we keep fixing our Fusions, we won't be in the market for their next supersynth = when they decide to rejoin the party . . .

Items of interest could well be - the source code for the OS for instance, or a way into the bios - so someone might FIX the external SATA.

64Gb CF cards would be nice too . . .

IMHO the error codes SHOULD be released, together with their technical implications - so we can at least get a handle on where problems lie . . .

Doesn't it just seem like - when stuff ceases to have a commercial value - it aquires a rarity value

Something tells me that Hell will freeze over, BEFORE anything gets released . . . .

Best Regards

parametric

[riffbeeper]

Brrrrrrrrrrr!!!!!!!!!

[tekuk]

I did ask Alesis for diagrams etc and they sent me the service manual via share it.
Not sure if i break anything by sharing it with this forum though...

Laurent