Roland JC-120H

[llanier0899@yahoo.com]

Having trouble finding problem with power. Never has been an issue. Just turned on yesterday and no power. Fuse is 5 amp fuse is good. when turning on, it shuts right off.

[nickb]

Having trouble finding problem with power. Never has been an issue. Just turned on yesterday and no power. Fuse is 5 amp fuse is good. when turning on, it shuts right off.

There are variations between years. In which year was yours made?

When you say it,'it shuts right off' do you mean the fuse blows? You can try pulling the secondary fuses and see the the primary fuse still blows to test the transformer.

[llanier0899@yahoo.com]

Not sure if yr. Im thinking 80s. The 5 amp fuse isnt blowing

[Jazz P Bass]

This schematic shows two mains fuses.

http://www.freeinfosociety.com/elect...C120-JC160.pdf

You can try measuring the resistance of the two line blades of the power cord.

With the power switch On, if all fuses & the cord are good, you should be measuring the power transformer primary.

[nickb]

Not sure if yr. Im thinking 80s. The 5 amp fuse isnt blowing

Via PM:

Fuse isn't blowing, when plug it in. My led light blinks and thats it.

That pretty much narrows it down to the primary and secondary connections to the power transformer. I think I'd thoroughly check all connections on the secondary and primary side not forgetting the lead & plug. Use the schematic Jazz linked to guide you. The power switch could be bad also.

[czech-one-2]

Heres some gut shots of an 82' if that's of any interest. They sure don't build em' like this anymore!

[oc disorder]

That's right , they build them like this !!!


Czechoslovakia has 240/230 power.


The pcb mount 5 watt wire wound resistors and the bridge rect. fuse board lead me to think its this one.
SM_JC-120_4th ed ~March 20 -79.pdf

[llanier0899@yahoo.com]

Czech-one-2 that seems to be the set up I have. The two fuzes that are inside looks like they are powdered. Are they made like that or? What are you suggesting I check

[czech-one-2]

Well, I'm the one on here asking for help, so hopefully somebody more qualified than me can help you. You mean your fuses are white,not clear glass? Thats ok,they make em like that. Unfortunate;y you cant see if those ones are blown or not.Fuses are cheap so go ahead an replace them with the same rated fuses. It may spring back to life. If not, then you eliminated one possible problem...