Barber Direct Drive not working, maybe power issues?

[xnery]

Hi everyone,

A friend gave me a Direct Drive stopped working for him. Although he wouldn't give me any straight answers, I think he may have fried something with an incorrect adapter. I don't see anything noticeably burnt out on the board, but here's what I notice:

- Bypass mode works
- No signal comes through when engages
- Status LED doesn't light up when engaged
- When engaged using an adaptor, a humming can be heard (humming not present when a battery is connected)

Otherwise, nothing on the boards looks like it's been tinkered with. I'm not sure what to think. Any ideas?

Thanks.

[slacker]

Best thing to do is make your friend tell you exactly what he did to it before it died, that would make it a lot easier to get an idea of what the problem is likely to be. Failing that follow the advice in here.

[aron]

The good news is that it's probably minor. Maybe a diode change and/or IC change. Check for power on the op amp pins.

[xnery]

Pin 1 shows 0.07, pin 2 is 0.05, and pins 3 through 8 are all 0.00.

That's with a battery reading 8.77 volts.

[xnery]

Also, the IC is a JRC 4558 in a socket. I tried a few different 4558's, but had no luck.

[David Barber]

Also, the IC is a JRC 4558 in a socket. I tried a few different 4558's, but had no luck.

There is a black 1n4003 diode on the right side of the PCB (black diode with silver band), just "snip & spread" one side of the diode and see if it powers up (9vdc - tip). It sounds like a simple protection diode. If the diode is the issue, just solder a new diode in place observing correct polarity.