Kicker 1302 Protection

[Scanlines]

Hi;

I've got an ix1302 that was in protect.

I found just one shorted TIP35C. I removed and replaced it.

I checked all outputs and drivers, they're ok, but the amp still goes into protection.

If I cut the B+ and B- jumpers to separate the power supply from the amp sec., it powers up and
I have +/-15V for the op amps
and from the center tap of the power transformer I have +35v and -37.5 up when those jumpers are cut.

I don't know if anyone has a schematic on this model or
even any advice.

Thanks in advance,
Scan

 

[Perry Babin]

If there is a PNP transistor connected between pin 14 and pin 4 of the TL494, remove it. This will disable the protection circuits and then you'll be able to see if the amp will play or if it has a real problem. If the amp works properly with the protection circuit disabled, you know the problem is likely due to a fault in the protection circuit. If the amp has excessive DC on the outputs or draws excessive current, then you can troubleshoot the audio fault.

With the protection circuit disabled, have all transistors clamped to the heatsink and have either a current limiter or a 10 amp fuse in the B+ line.

 

[Scanlines]

Hey Perry;

You nailed it ! I pulled the pnp out and the amp works fine.

I take it that this is probably characteristic of this model.
Either way, thanks a lot !

Scan

 

[Perry Babin]

The over-current protection transistor that's connected across the emitter resistors for the blown channel is likely shorted or leaking.