Hi guys.
Getting to the end of my tether with this one. The R100 uses 4 output tubes, all EL34's. With the amp on standby, the heaters glow and everything seems fine. With no guitar connected, I flick the standby off and everything is still fine, last test it ran for over an hour with no problems. The trouble comes when I plug my guitar in and play. After roughly 5 mins, the amp slowly dies and the tubes no longer glow. I opened up the amp and found fuse F5, 10amps blown. This fuse is on the output tube circuit board, and is protecting the 2 green wires coming from the primary transformer.
I have changed all 4 EL34's for JJ's, and have biased the amp to 41v per tube which is in the middle of Rivera's specs. I have posted this on their forum but the place is like a ghost town. Any help would be greatly appreciated.
Anyone have any suggestions ?
Rivera R100-212 problem
Moderators: pompeiisneaks, Colossal
Re: Rivera R100-212 problem
Hi there,
I've never seen inside one of these amps before,so I don't know the
layout.Is it possible that the heater wires are shorting out somewhere?
The other thing that comes to mind is a possible intermittent short inside
the power transformer.
cheers
paddy
I've never seen inside one of these amps before,so I don't know the
layout.Is it possible that the heater wires are shorting out somewhere?
The other thing that comes to mind is a possible intermittent short inside
the power transformer.
cheers
paddy
Re: Rivera R100-212 problem
Hey thanks for the reply.
Had a few hours on it today. It looks like the fuse carrier has had a bit of heating in the past, and looks a little carbonised. I removed the fuse carrier from the board and soldered in an inline fuse holder ... and BAM it works !
Seems like the fuse carrier leaves weren't giving a good enough connection to the fuse, and instead of blowing the fuse with excess current, it was actually melting the solder inside the fuse and causing the open circuit. I have ordered a new fuse carrier, but will leave this mod in place for now.
Panic over.
Sorry to have posted this on your "amp builders" forum, but seeing as there are a lot of techy minds on here, I thought why not.
Had a few hours on it today. It looks like the fuse carrier has had a bit of heating in the past, and looks a little carbonised. I removed the fuse carrier from the board and soldered in an inline fuse holder ... and BAM it works !
Seems like the fuse carrier leaves weren't giving a good enough connection to the fuse, and instead of blowing the fuse with excess current, it was actually melting the solder inside the fuse and causing the open circuit. I have ordered a new fuse carrier, but will leave this mod in place for now.
Panic over.
Sorry to have posted this on your "amp builders" forum, but seeing as there are a lot of techy minds on here, I thought why not.
Re: Rivera R100-212 problem
Glad you found the problem. 
Man, sometimes these tube amps can kick your ass.
I'll have to remember that one.
Man, sometimes these tube amps can kick your ass.
I'll have to remember that one.
Tom
Don't let that smoke out!
Don't let that smoke out!
Re: Rivera R100-212 problem
Ah yeah thats an understatement. I bought this amp from a guy who's father used to play in Dire Straits (apparently just before they made the big time). For 3 years I had no trouble at all, massive clean sound and so much punch.
My band had a gig last year, toward the end of the summer. It was in the garden of this wealthy businessman, and was a lovely day, but the dew came down as the sun went down, and everything got a coat of moisture. Since then, my amp had a few niggles here and there.
Its true with amps that you may know a lot, but theres always something there to bite you in the ass. This one seems so obvious in hindsight, but was probably too obvious.
Lesson learned, everytime I take out a fuse now, Im gonna clean the leaves with some wire wool !!
Cheers guys
My band had a gig last year, toward the end of the summer. It was in the garden of this wealthy businessman, and was a lovely day, but the dew came down as the sun went down, and everything got a coat of moisture. Since then, my amp had a few niggles here and there.
Its true with amps that you may know a lot, but theres always something there to bite you in the ass. This one seems so obvious in hindsight, but was probably too obvious.
Lesson learned, everytime I take out a fuse now, Im gonna clean the leaves with some wire wool !!
Cheers guys