Behringher PMP 1280s Resistors??

[MARSHALL BUSTER]

Hey hows it going guys.

While having a clearout the other day i found this amp again in a box where i abandoned it last year.

Tonight i removed the screws i couldnt bother removing last time and BINGO i found the likley cause to my problem.

The 30 miliohm resistor {(R137)0E03} on channel B is blown to nothing, so i guess thats why no sound on B then!! the board is HCA2400

** My problem now is i cant seem to find a place that sells them!, could you please give me any part numbers or descriptions that will help me order the part?**

Nice one guys take care.



One other thing, the mixer section is playing up too. The lights are light up on the left level meter to max and no power seems to be going to the DFX displays!! Any ideas please??. I have unpluged all wires from the damaged amp board and tested it.

[Jazz P Bass]

There may be other issues that 'made' the resistor blow up.
Check the mosfets for gross shorts across the leads.
If the output section is working, you should see a signal at the junction of the two mosfet drains. (T22 & T25)
First thing that comes to mind is 'can you effectively remove all of that carbon?' (it is very conductive)
The resistor is available at Digikey.
I am not sure of the wattage.
At 0.03 ohms it seems that it would be more of a fuse than a resistor.
http://www.digikey.com/scripts/dksearch/dksus.dll

[Enzo]

Mouser sells then, and they are a standard commodity part, I'd expect them to be available in the UK as well.

0.03 ohm (30mOhm) 2W 1% KOA SL2 is the description.

That resistor is in series with the output, right? Meaning it burnt up probably because the amp output failed, putting DC through the load and triggering the output crowbar on the output jack board.


Isopropyl alcohol and a cotton swab ought to clean a lot of that soot off the board.

[Enzo]

Ah, yes Digikey has a better selection than Mouser.

"Current sense" resistor is the term to search for,

[MARSHALL BUSTER]

Great Thanks Jazz & Enzo il get on to sorting that out in the morning,

I added a part to my first thread about the mixer, im wondering whats gone wrong with this baby in the first place

[Jazz P Bass]

As to the mixer acting up, first & foremost the power supplies must be present.
+12, -12, +5 & -5.
Check them.

[Enzo]

May I suggest you don;t go back and change older posts, even if they are an hour old, it can get confusing for us folks who already read it. Most times I don't go back and reread through a thread. Just add it at the end here. My opinion only here.

IIf all yourt peak lights are stuck on on a mixer - most any mixer - it usually means a missing 15v rail.

[Bryan1968]

I have had the same issue with my amp. (Actually, an amp that was given to me - channel 'A' was blown). I replaced all of the high-powered components in the power side, but had some difficulty in finding the 'R-138' current sensing resistor (without waiting for an 11 week lead time).

Instead, I ended up using this.

12FR030E Ohmite | Mouser

It was easy to bend the leads to fit, and now I have a perfectly good (free) amp in 100% working condition. It never hurts to think outside the box............