Need assistance in getting details of part number for power mixer

1. Check the power cable and ensure it is securely connected to both the amp and the power outlet. 2. Check the fuse and replace it if needed. 3. Check the power switch and ensure it is in the correct position. 4. Check the battery (if applicable) and replace it if needed. 5. If the amp is still not turning on, contact Roland customer service for further assistance.

How can you state power supply is working excellent, please?

Disassembly the unit.
Your question is less detailed. If the keys is broken,replace with new.
If you mean "How to",then you need the service manual.
Outputs problem,usually causes by output IC (or input IC) is defects.
It also can cause by AD/DA IC is error.

Hi, With my sound engineers hat on I would use a small PA. mixer, amp and speakers!!!!
For quality you need a full, flat frequency range system with good headroom.
I assume this is for your own listening, when using an acoustic kit?
There are one box solutions.

1. Drum amps. Like a monitor wedge with an amp, Roland do a PM-10, Various other makes are available.
2. General purpose powered wedge.
3. Keyboard Amp, these are full range and available in various sizes.
4. Bass amp with high frequency driver (tweeter), not the best but will have good bottom end.
5. Powered or active speaker, much like a powered wedge, but a different shape, needs an input volume control.

All these systems need to have large bass units, 10 inch minimum, and will be in mono. Two will give you stereo,
How loud depends primarily on the sensitivity of the speaker. But manufactures insist on selling things by power. Worth looking this up.
At a couple of feet away, 20 watts should do it, with high sensitivity speakers, more likely you find most things as above start at about 70 Watts.
Good luck, I hope I have widened you choices a bit.
All the best, Chris the Fader.

If the third prong is the round one, then that is the ground to your amp. It will still work, however, the amplifier will not be properly grounded. So in a pinch you can use it, but you need to get the cable replaced. The ground wire is there for your safety, in case you plug your amp into a mis-wired outlet or if you are plugging in another instrument like a keyboard, mixer etc. that may be mis-wired. This could lead to a bad shock or worse. You have been warned.

https://www.amazon.in/Roland-JC-120B-Chorus-Guitar-Amplifier/dp/B00S0J6IS6


JC-120B 1975 or later

JC-120UT After 1984 - I haven't found the way to identify your serial number online. You may need to post a message on one of the many internet boards shown.

https://www.ssguitar.com/index.php?topic=2243.0

http://music-electronics-forum.com/t35754/https://www.gearslutz.com/board/so-many-guitars-so-little-time/181432-roland-jc-120-tough-date.html

JC=120UT /JA sold in Japan only.

https://www.gearslutz.com/board/so-many-guitars-so-little-time/181432-roland-jc-120-tough-date.html


ervicerepairmanuals.net/others/roland-jc-120ut-searvice-manual/






http://ervicerepairmanuals.net/others/roland-jc-120ut-searvice-manual

Yep! Get a decent audio interface that attaches to the PC with a USB connection and uses BALANCED lines to your mixer. I use a UA-25EX Roland/cakewalk as an example. (about $200 and there are cheaper units such as M-Audio Fast Track MKII ) Note these interfaces BOTH record and playback with two channels for stereo.
Essentially the audio board that is in PC's and Laptops are too near the switching noise of the processor and some of that is just bound to get into the audio lines as they don't even have balanced audio lines from the computers. Make sure you use either TRS or XLR balanced cables from whatever interface you get. Also connect ALL interconnected equipment to the same power source or receptacle. You can try to reduce the buzz with the mixer EQ's with what you have, but that sacrifices audio quality.

I tried to post a possible solution and it may have not made it so I will try again.

Download the data sheet for an LM3886.

This chip is used in a lot of linear audio amps in the 50 Watt range.

Download the data sheet and then check if connections on your unit make sense.

Smaller units sometimes use the TDA2050 7 lead TO220 style chip so look at that one in the LM3886 isn't the one.

I need a transformer part 32 no:11-32-000 class 2 ac power transformer mod:mw48-090200a Input:120 ac 60hz output:9vac 2000ma.
(UL) US Ite powuer supply made in japan