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NAD C162 pre-amp. No lights, no sound. Kill-a-watt says zero current is being drawn, power switch measures good, but power transformer's primary measures open.
The transformer is a custom toroidal design, a Noratel TI-6766B.
I found this thing in the e-waste at work, hoping any fix would be cheap. But I don't think that's going to be the case.
Any suggestions, or should I put it back where I found it?
Kind of a long shot, but only costs time. Peel the insulation off of the transformer and take a look. Sometimes it is a simple problem. In this case, with an open primary, the primary coil may be (un)soldered to the wires that leave the transformer.
I've had about a 50% success rate in fixing transformers of different types, but it is more frequently a short to the case or core.
This idea appeals to me. The secondary wires simply unplug from the circuit board, so only the two primary wires need to be desoldered from the back of the power switch. If the plastic wrapping around the toroid is easy to peel back, it's definitely worth a shot. I'll take a look this weekend. Thanks!
Replying to my own post - since there is no fuse visible on the primary, I suspect a thermal fuse in the transformer. I haven't peeled back the wrapper yet to investigate, but if the problem is a blown thermal fuse, I can remove that, and install a suitable fast blow fuse external to the transformer in its place.
I did email the transformer manufacturer (Noratel). We'll see what they say...
I doubt Noratel will tell you anything, let alone sell you one. Your best bet is to contact Lenbrook Industries, the distributor and owner of the NAD brand.
Or contact a NAD service center and ask if they can get one.
There's one not far from here. Worth a shot. Thanks!
Heck, worst case is they ask to install it and you have to pay. But at least you have a $1000 preamp.
So worth fixing, then? Seriously, I had a NAD 1020 many years ago that I thought sounded fine, but NAD has always in my mind been "nice design, but built to a price point". (My 1020 had a factory original crack in the circuit board repaired by a factory original jumper wire soldered to the traces. I was not impressed.)
I wasn't in the market for a preamp (I have an old McIntosh that works fine). If the NAD is worth fixing, I'd gift it to my brother whose new U-turn Orbit turntable is in need of a decent preamp.
So I'll see what I hear back from the transformer manufacturer, the NAD distributor, and the local repair shop, and go from there.
Thanks for everyone's recommendations - much appreciated.
Thanks - I'll try that.
The power supply schematic is in the attached link to HiFi Engine's fine website. The supply is quite complex providing +/- 52VDC, +/- 26VDC, 12VDC, and 5.5VDC- all regulated. It doesn't seem to note the transformer voltages of the secondary windings anywhere. Anyhoo- you're not gonna find that baby down at the Dollar Tree. I'm guessing your only hope is to find an exact replacement- wait for a "parts only" unit to show up on eBay perhaps.
Thanks for that - I have the service manual, and saw the range of output voltages. There are ten wires on the secondaries - two connectors with 5 wires each that connect to the main circuit board. Not your typical design.
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