Supported appear in, Roland's in the beginning offerings were the entire membranophone machines. Database of Roland mass production dates.
ROLAND JC 50 SERIAL NUMBER PLUS
The series numbers never-endingly clobber manufactured past the Roland Corp inform you the period plus twelvemonth the symbol unpronounceable turned the. JC, JC, JC, JC, JC In support of Bully outcomes gratify using the Order about intellect seeing that with the purpose of has an superfluous Imprint individual shape plus has the Bully. Roland series numbers square measure both 6 numbers, or else 6 or else 7 characters in addition to 2 letters close-by the bug out. The good news is that when it's still yellow it's got the texture of extremely aggressive bubblegum and relatively easy to remove.Roland ac 60 nonparallel bunch life-span. Any of the glue that hasn't changed colors and turned to evil eventually will. At least where it touches component leads, traces or terminals. Any of the glue that has changed colors will have to go. If it means desoldering something to get under it, so be it. You will want to scrape this off your circuit board. This is especially a problem on ribbon cables soldered to the board, but you'll find it elsewhere. Very common problem in a lot of Yamaha products and an occasional issue for Roland. Sometimes this glue pollutes the solder joints and creates a bubble around the component lead. Like I say, it's hard for me to see in the photos, but it looks like you've got some on the caps. By the time it has turned brown it has become rock hard. Over time it discolors and turns brown, this also turns it from a beneficial assembly aid into a corrosive, conductive and occasionally semiconductive mess that will cause all sorts of weird problems like crackling, buzzing and hum. Roland used the same yellow assembly glue as Yamaha and a lot of other Far East manufacturers. Specific to Roland and it's sorta hard to see in the photos with my color vision. Those may just need resoldered or may need replaced. The usual cause of loud power-on thumps is filter caps. Then there is the green ground wire that grounds both speakers at each of the speaker mounting holes. The orange and red wires are connected right to the board and go to the left and right speaker hot terminals, and the brown and black wires come off the other terminal and go straight to the left and right line out. Yes, the line out cable essentially comes from the speaker itself. I have not tried an external cabinet yet, and that is a good idea as the higher frequencies are having a less adverse effect on the noise issue. So No, the amp did not vibrate when I tested the line outs. The cabinet was very loose when I first received the amp, and I know there was some vibrating going on there, so the first thing I did was tighten all of the nuts and even added a few nuts where needed to take the cabinet out of the equation. If you run both line outs, it defeats the speaker output to the speakers so no speaker activity when I was testing the line outs which sounded pristine in my Mixer. RE: using the amp speakers while I was testing the line out. I tested each speaker separately with an old GMT amp and they sounded just fine. 1980's ?Īny help or advice on my noise issue would be greatly appreciated. The amp looks to be one of the older USA models. I took several pics of the inside of the chassis that I can post but I did not notice anything disconnected or that looked wrong, but I'm not an amp tech. I double checked and made sure the speakers are wired correctly. I thought the speaker(s) were blown, but they tested just fine. I tightened all of the cabinet and speaker screws to make sure there is no vibration to cause any noise.īut I am still getting some buzzing and other noises that I can only guess what the cause is.Ĭould it be caps? The amp turns right on with a loud popping noise when I turn it on. I noticed a wire disconnected to the middle of one of the rca connections to the reverb pan and soldered it, but this did not fix the reverb circuit issue. Line outs sound great and all of the chorus tremolo ciruits and all pots on the amp work like they should. I have troubleshooted the line outs and they are fine. I have troubleshooted the speakers and they are fine. I have some noise issues with the output to the speakers.
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