us acoustics usl2100

[jordan_ciaramit]

I need schematics or someone with another one of these to tell me the transistors used in the power supply and outputs. It may be the same as the usb2100 maybe

[jordan_ciaramit]

I also need the part numbers on the rectifiers. So everything on the heatsink pretty much.

[Perry Babin]

If the gate resistors are 100 ohms, they probably used the IRFZ44 or something very similar. The Z44 should be a good sub.

If the rectifiers are in the TO-220 case and are common anode and common cathode, the MUR1620CT and MUR1620CTR should be good subs.

Generic outputs that work in most of the amps that use large outputs (unless they're using TIP35C/36C) are the FJA4213 and FJA4313.

Check with the manufacturer to see if they can send you a schematic diagram or the original part numbers.

[jordan_ciaramit]

OK I have irfz44n in the power supply and tip35c/36c in the outputs it comes on and idles around .5amps but if you have a signal connected and hook up a speaker the current spikes and one bank of the power supply gets hot and the current stays ramped even if you disconnect the speaker. It doesn't seem to do this if there is no input. The rectifiers are different part numbers could this be causing the problem? I also am pretty sure I have output on both channels.

[Perry Babin]

If the amp didn't use TIP35/36 originally, they're typically not a good sub without modifying the bias circuit.

The problem is possibly the drivers for the power supply FETs. Did you check them?

[jordan_ciaramit]

I did check them in circuit but I need to take them out and test them I may have 2 bad 2sa1268. This is same part that always fails in memphis class d amps. I think the original outputs may have been 2sb688/2sd718 I will try swapping them tomorrow. Would this thing idle okay if the drivers were bad?

[Perry Babin]

It may idle OK, especially if it's a regulated power supply.

[jordan_ciaramit]

Okay I pulled the drivers and they are good. I replaced the outputs with 2sb688/2sd718 and it still does the same thing, idles at .5 amps hook up a speaker with no audio signal and half of one bank of transistors starts to get hot fast and the current draw goes up to around 3 amps(its a 3 amp PS). I checked every transistor on the board(diode check) and they seem to be good I checked all diodes and they seem to be good. I leaning towards a IC or transformer?

[Perry Babin]

Is there DC offset on the speaker terminals?

[jordan_ciaramit]

481mv on one channel 369 on the other.