Repair protection circut

Blowing fuses, was caused by many thing.
Short of rectifier,resistor,elco,tube heater,tube pin, and also trafo itself (primary or secondary winding). It must check step by step.
CAUTION :
THIS IS HIGH VOLTAGE AREA.
RISK OF ELECTRIC SHOCK THAT CAN KILL.
DON'T DO THIS IF YOU ARE NOT TECHNICIAN OR NOT FAMILIAR WITH VACUM TUBE CIRCUIT. THE CIRCUIT MAY STILL CONTAINS ELECTRIC SHOCK EVEN IF IF THE AMP IS NOT POWER PLUGGED.

The simple steps (see picture) are:

1. Disconnect all connection from secondary of power trafo (PLV,PDCH,PACH and PHV).
   Power ON the amp. If fuse is not blowing,trafo is good.
2. Power OFF the amp. Unplug the cord.
   Connect PLV1-PLV2-PLV3 (this are Bias voltage,+/-15VDC and Backlight PCB voltage) to power trafo.Power ON the amp. If fuse is not blowing,PLV circuit is good.If fuse blowing,there are parts is damage (dioda,elco,7815/7915,resistor) in this PLV circuit.
3. If step 2 is good,go to next step.
   Power OFF the amp. Unplug the cord.
   With PLV circuit stay connected,connect PDCH 1-2 and PACH 1-2 to power trafo. Power ON the amp.
   If fuse is not blowing,PDCH and PACH circuit is good and all tubes heater/filaments are lights after a few seconds.
   If fuse blowing,there are parts is damage (dioda,elco,tube heater pins) in this PDCH/PACH circuit.
4. If step 3 is good,go to next step.
   Power OFF the amp. Unplug the cord.
   With PLV,PDCH,PACH circuit stay connected,connect PHV 1-2 to power trafo.
   Power ON the amp. CAUTION: HIGH VOLTAGE AREA is ON.
   If fuse is not blowing,PHV circuit is good.
   If fuse blowing,there are parts is damage (dioda,elco,tube pins) in this PHV circuit.

.
Notes:

• Steps had to be done sequentially from 1 to 4, not upside down.
• If tube/heater pin is short,it can't be repair. The tube must be replacing.
• PDCH circuit is voltage for V1-2-3-4 heater/filaments.
• PACH circuit is voltage for V5-6-7 heater/filaments.
• Always replace fuse with same type.

Sadly, when the circut get damaged by a fluid, it typically has to be taken to a local professional so that they can pull the board out and run tests on it. This is a very intensive process because each componant within the questionable area of the circuit needs to be tested for weaknesses or damage. Most of the time you will pay more for labor than parts, if you want the unit repaired.
I recommend getting a quote and keep your mind open to replacing this unit due to the repair versus replacement.

The limiter probably delayed the eventual damage. Nothing prevents all damage absolutely.

Generally speaking, an amp protects itself from heat, shorts, overloads and operator exuberance by refusing to turn on or stay on.

Overloads can be from excessive periods of high output or marginally low impedance loading by the speakers; and shorts would be wiring issues or a speaker blowing up.

You should be able to feel if it's hot. WHY is it overheating? Make sure it has sufficient ventilation on all sides and that vent holes are not blocked by dust balls. Ensure the fan (if equipped) is running as designed (some only operate on demand). Clean dust and debris from it.

If the amp comes back on after cooling, you're lucky. They only have so many self-protection cycles in their lives so continuously resetting or cycling their power without addressing the cause can do more harm than good.

If it protects immediately on a cool power up you should disconnect the speaker connections and try it 'naked'. If it comes up then diagnose which lead(s) are shorted. If it does not come up the problem is internal and should be left to an experienced and competent hands-on tech for forensics and further action.

Check for loose speaker connections at the speaker as a root cause for intermittent shutdown.

It seems there's another component (a capacitor, a diode, etc) causing a short circuit to triac and transistor, or there's an over voltage on this stage, please check if the voltage is according to the one feeding the good channel.

This is a problem that may likely require the skills of an experienced repair tech. If you are not comfortable working on electronic devices, find someone who can do it for you. UNPLUG YOUR SPEAKER BEFORE INSPECTING A PROBLEM.

The first place I would look is the FUSE. Each of the speakers contains a power amplifier and each has a fuse that will blow to protect the power transformer, circuit and speakers. If you are getting NO POWER at all to the speaker, check the fuse first. It is located on the AC plug circuit board.

You can download the PDF for the HS series here. It includes all of the circuit diagrams, parts lists and close-up photos of the parts.

If the fuse is not the problem, the speaker's power amp has suffered more sever damage and you would certainly need an experienced technician to diagnose the problem.

Good luck!

This probably means there is a failure and the internal protection circuits have activated. It will probably have to go to a shop for repair.

Here is a link to the manual:http://lib.roland.co.jp/support/en/manuals/res/1811247/KC-60_e2.pdf Page 9 states that there is a protection circuit built into the power supply. Follow the directions for turning the power on in the manual. If the amp doesn't power up you will have to have it serviced by a qualified Roland tech as there is likely to be some damaged circuitry that won't be repairable without the schematic, parts and safe repair procedures.

No, that is NOT what the problem is.

The fuse protects the power supply. The power amps have failed. The usual cause is an arc between layers of the multi-layer circuit board. The labor to repair the power amp module is extensive. I have repaired several.

You can find new amp modules and I would purchase a new one and drop into your unit. The amp module is an HCA2400.

There is probably $15 of parts blown in each side of the power amp and it takes about 6 hours to repair. One has to grind out the burned area (internal layers not necessarily visible on surface) and re-insulate and then install jumper wires to replace those taken out.

Each side of the amp will likely take out 3 switching MOSFET transistors and often a Zener diode. Sometimes a low resistance metering resistor will be fried with smoky residue underneath the board. When this happens two small surface mounted resistors will be blown open. Great care has to be taken when insulating the board damage and replacement of the blown circuit traces.

You can find HCA2400 power amp module replacements for about $175 online.

Use of the unit as an unpowered mixer is a bit dangerous as if arc re-establishes it can fry the power supply taking out two very expensive IGBT's and many other components. If the mixer still works, then your whole power supply is still OK.

I had to repair mine. An arc had occured between circuit traces and a heatsink in the power amp and that took out a half dozen transistors, a switching regulator chip, two power resistors, diodes. The parts are all available BUT you must be very careful to weed out ALL the bad ones.

AFTER repair, put a 150 wat light bulb in series when powering up to avoid damage IF there still is a bad component in the circuit.

After cutting out the damaged board and replacing the parts it is all working again.

I had to trace out some of the circuit to troubleshoot as Behringer won't give out schematics.

The amplifier in this is a class "D" switching type. Be very careful of running the unit if the speakers are not connected.

I just fix this unit,
1 Nch IRF140N
1 Pch IRF9140N
1 0.1 ohm 3w resistor at one of the mosfets
1 47 ohm 1/4w
1 220ohm 1/4w