New Member / Hello! / Roland JC-55 Question

[Taylorplayer]

Well, lo & behold, I have a blown speaker!

[Taylorplayer]

To all - My amp problem has been (re)solved! I thought I had a blown speaker, but that was not the case. Read on -

First of all, my thanks to everyone who replied, and in particular, to Bill 52. He gave me several more steps to follow, to determine if my speakers were actually working or not:

"How did you test the speakers, only by swapping the output leads? Make a note of the speaker wiring color codes, I think that the orange and brown are one set of outputs and the other set are the red and black. Remove one wire from each speaker so that the amp is not connected when you do this test. Take a 9 volt battery and touch the terminals of each speaker. there are two things that you can learn from this test. If the voice coil is okay you will hear a pop from the speaker. Secondly you will see the cone move forward or backward when you touch the battery to the terminals. The Roland speakers are usually marked with a small stamped + and - sign on the insulator. When the positive battery terminal is touched to the positive speaker terminal the cone should move forward. Check your new speaker to see that the polarity is the same or reverse.

Once you know that both speakers are working, first connect one set of output wires to the speakers. If you pulled one wire from each speaker for the earlier test, just reconnect one speaker for now. Make sure that the second speaker wire is not shorting to anything. Turn on the amp and see that the first power amp is working. Make sure to test all three positions of the chorus switch. If the sound if there for all three switch settings, shut off the amp and test the second power amp and speaker the same way.

You should find out if both power amps are working and if they both work in all chorus switch settings. If both power amps are working in all postions, the speaker phasing is the only thing that I can think of that could cause you problem."

My reply back to him was as follows:

"First I tested each speaker using a 9 volt battery and I did get a loud "Pop". Then I reconnected the speakers. The left speaker (when viewed from the front) produced sound from all three switch settings when just one set of output wires were connected. Following the original set-up, I connected the red / yellow set of leads to it, leaving one pulled from the other set.

The right speaker produced no sound at all from any of the three switch settings when just one set of output wires were connected. Again, following the original set-up, I connected the brown / black set of leads to that one, leaving one pulled from the other set."

Bill 52 then replied as follows:

"I don't know the history of your amp, but the speaker wiring seems to be wrong. Looking at the back of the amp connect the yellow to the left speaker positive terminal and the brown to the left speaker negative terminal. Connect the red wire to the right speaker positive terminal and the black to the right speaker negative terminal. Now see what happens to the sound in all three chorus positions."

My response:

"When I received the amp I carefully noted the which lead had been connected to each terminal. As it turns out, they were not hooked up correctly, so when I reconnected then each time they were wrong. Once I hooked them up as you described, I then had proper sound from all three switch settings - and from both speakers!"

Once again, my thanks to all who helped me out with this.

Peace.
Will