Alesis MidiVerb II Schematic

[stosostu]

I need a schematic for the Alesis MidiVerb II rack reverb unit, or alternatively any clues on what might be causing it to oscilate in both channels and all selections.

Any help is appreciated.

[Enzo]

Contact Numark and see if they can provide the schematic.

As to the problem, first thing I check is the power supplies. I am sure it runs on either +/-12 or +/-15 for the analog, so check those supplies for both up to voltage and for clean. I'd imagine the digital stuff would run on +5 and if the patches seem to dial in, it may be OK, but check.

[stosostu]

Thanks Enzo. It runs off a 12V AC plug pack and the internal power supply provides +/-15 V DC, but I've checked that and it is OK. I am awaiting a schematic from the local distibutors in Oz.

[Lancey6969]

I have a MidiVerb III service manual... let me know if you think it might help?

[pecorporation]

sure!

[stosostu]

Thanks Lancey6969, but the II and the III are very different beasts. Fortunately, since I posted the request I have been able to find and fix the fault. It was faulty caps in the power supply. The voltage measured OK but on a scope it had extremely high ripple (hence the oscillations I expect).

[jrfrond]

It was faulty caps in the power supply. The voltage measured OK but on a scope it had extremely high ripple (hence the oscillations I expect).

A malady plaguing almost every single piece of rack gear Alesis ever made, to wit, the cheap 1000uF or 2200uF main filter caps, as well as the occasional shorted .1 decoupling caps.

[doctor]

A malady plaguing almost every single piece of rack gear Alesis ever made, to wit, the cheap 1000uF or 2200uF main filter caps, as well as the occasional shorted .1 decoupling caps.

Hi Lancey6969,

Please upload MidiVerb III service manual.

Thank you in advance,