HARMAN KARDON 330B - Roached Resistors, No Output!

[JB8]

Here's what I know:

• Unit powers up, no sound, no output at all across all functions, no voltage at speaker terminals
• Inserted outside source into main amp in's, no sound
• Pulled the bottom cover to check some voltages, was getting roughly 54V DC at the test lug (B5) at what I'm assuming is tied to R918 and the + side of C912 (pictured). I'm not getting any power to the main amp board, at all
• I also noticed a roached resistor at R914, so I pulled it as well as R918
• R918 tested at 970 ohms, assuming it should be 680 per the schematic?
• R914 tested at 2.2K ohms, and that should be 820?

Since I'm working from the 330A/B schematic and there's no specific parts list for the B I want to make sure I'm tracking down the correct values for replacements, both ohms and wattage, would certainly appreciate an assist here.

Thanks all, hope your week is off to a great start!

 

[llwhtt]

Those resistors look to be 1K and 2.2K.

 

[JB8]

Thanks for the quick response, @llwhtt , I'm surprised they tested so close to spec considering how terrible they look, crazy. I'll replace them and start looking for other causes for the dead amp, hopefully I can figure it out but I'll reach out for more help if I need to tap out. Thanks again!

 

[newenglandj]

Did you check the fuses?

 

[dlucy]

Here's what I know:

• I also noticed a roached resistor at R914, so I pulled it as well as R918
• R918 tested at 970 ohms, assuming it should be 680 per the schematic?
• R914 tested at 2.2K ohms, and that should be 820?

Since I'm working from the 330A/B schematic and there's no specific parts list for the B I want to make sure I'm tracking down the correct values for replacements, both ohms and wattage, would certainly appreciate an assist here.

Those look the ones on the secondary rectifier board. Very common failure.

I recommend you start with the "which 330 do I have" part of this thread: https://www.audiokarma.org/forums/i...a-330-330a-330b-b-1-330b-b-2-and-330c.960045/

 

[JB8]

Thank you both, appreciate you hopping in!

The fuses checked out "fine" upon first inspection, but after pulling them again I think they may have been the issue, or at least part of it... The elements looked intact but I hadn't put them on the meter, so that's on me. After seeing the resistors I just assumed they were the issue. Another lesson learned - put your fuses on the meter, a visual is not the best test method. AND, resistors are tough! Those two look so wrecked but I assume they were still doing the job.

Thanks for the link, Doug, looks like this is a B-1 series, great to learn the differences, excellent thread!

After I get the new resistors installed I'll update this thread with my findings, hopefully others can learn from my mistakes, ha!