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Hi
Primaluna Prologue Classic has a bias protection circuit for output tube shorts.
Blew a KT90 on turn-on, LED turned red, amp went into protection mode.
Put back in EL34 tubes, which I know are good (just played them), waited at least two minutes, turn back on, no output. Tube heaters work and LED is green.
Primaluna uses a relay in the bias circuit, which is where the plate fuse in used to be.
Took the amp out of my system for now. Did I just not wait long enough?
It was a pretty bad arc in the KT90. Relay is a omron g5nb-1a-e
Does it have to cool down to reset?
Thanks
Greg
Follow Ups:
It is a sub $3 part at Digi-Key...
Dman
Analog Junkie
Edits: 06/29/16
I contacted Primaluna about this. They said it's "very rare" that the relay blows, but it can happen for a KT90 failure. The failure was spectacular - lit up like a Christmas tree.
I think it's the relay, but who knows. I'm not confortable with the repair so sending it to a local shop that repairs Primaluna.
I turn mine off for a full 5 minutes and it always resets. That said, when I first got this unit (a Dialogue 2) the relay had to be replaced. It was apparently defective and showed early signs of this by its tendency to trip very prematurely.
Is the amp still under the warranty period?
Call Kevin @ Upscale Audio, since he is the distributor.
I have the Dialogue HP which had a similar problem that turned out to be the relay.
Kevin will steer you in the right direction finding the repair shop.
Is the relay SOCKETED?
If so, you could TRY one.
I don't know the potential downside or what Else could have been damaged in a tube arc.
Too much is never enough
Thanks. Unfortunately I bought it second-hand.
My local shop is a Primaluna dealer though.
Did yours just need a new relay?
Yes, Luckily it happened while under warranty.I would think such a repair isn't terribly expensive. Good luck
Edits: 06/28/16
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