Rickresource Rickenbacker Forum

I have a great used Crate combo with 4 EL84s and 4 12AX7s (I think). Anyway it has a rich clean channel and a nice drive channel. Once or twice over the last few months it would
come on when turned on and then FADE off and then come on and stay on. Last night it did the FADE off twice and stayed "out" with the on switch still glowing "ON". I pulled the chassis and I could see that all 8 tubes were on (or at least glowing).

Any diagnostic ideas to forewarn me about before trusting it to a technician. What would make it gently stop like that? No smells or noise. Nothing through the original Crate
heavy duty speakers. Just ON but "nobody's home". Suggestions, please. I am not an electronics guy, but the chassis shows no appparent damage that I could see.

It also occurs to me that to turn it on I was toggling both the "on" switch and the "standby" switch next to it so they both glowed ON - this would usually make it stay on. Now
would not turning the standby "off" have been contributing to a problem? Thanks.

Many of the newer amps that use PCB's also use the grey ribbon connectors to connect things together, and these are just a lousy way to connect and will often cause intermittant failures. I haven't seen one of those particular amps but it wouldn't surprise me if they use those type of connectors.

Regardless of the failure mode, some troubleshooting will have to be done....injecting a signal in at the input, and tracing it though the amp to find out where it stops....any good tech can do this. (or should at least)

Not using standby doesn't matter overly much. You don't even really need a standby unless you are running very high votlages such as an Ampeg SVT uses, and that is just getting into the territory where it is a good idea to have a standby. Don't worry about that.

Greg

I found this place here in town (St. Louis). L.S. Electronics offers warranty service on over 90 manufacturer brands past and present including Ampeg, Akai, Crate, Fender, Gibson, Jay Turner, Korg, Line6, Mackie, Marshall, Peavey, Roland, Warwick, and Yamaha. And the owner used to be a designer for tube Crates.

Anyway, in case this symptom happens to one of you, it was a bad resister, and a shorting tube (which could have but didn't-they checked it-cook the transformer). So, for a
diagnosis at $60.00/hr bench time, re- tube with non chinese, also fix some bad solder and replace a couple of head stripped wood screws: about $200. Not too bad since the amp is used and may not have been looked at in 10 years or so.

Sometimes you just can't do it all yourself. Nice, helpful shop that does nothing but musical electronic repair and guitar set ups.

However, thanks for the response, Greg.

Glad it was an easy fix!

Greg