We have a SV168n-36 Spagna Vetro Range Hood and it works well but the lights are having problems now. They only come on intermittently and when they do come on once they heat up they shut back off.
I had the exact same problem with my Spagna Vetro hood. The fan worked fine, but the lights started working intermittently and then stopped working altogether. The problem in my case was a failed transformer, which sits between the power switch and the lights and is necessary to step-down the voltage from conventional 120v to 12v to support the halogen bulbs in the unit. Although there are several steps to resolving the problem (replacing the transformer), it's really not difficult. Here's what I did to solve the problem:
1) Shut off the circuit at the breaker (always very important :^) )
2) Removed the glass arch from the top of the hood. Four screws hold it in place and are accessed from above the unit.
3) Removed the access panel above the fan and light switches. This panel is visible underneath the glass arch, when the glass arch is removed. I slid the lower section of the decorative stainless chimney cover upward to gain complete access to the back two screws of this panel.
4) I unplugged the original transformer from the light on/off switch (connected with two yellow wires on my unit). Remove the wire-nuts and disconnect the 12v leads from black and white wires that connect the transformer to the halogen bulb fixtures.
5) Using a flat-head screwdriver, I pried the transformer off the metal surface to which it was adhered with double-stick tape. This was strongly adhered and took a bit of prying.
6) Found a replacement step-down electronic transformer at the hardware store. My hood takes only two 10 to 20 watt bulbs, so only a small transformer is required. The original one I removed was rated to 70 watts max. I replaced it with a transformer rated to 60 watts max. Either was more than sufficient to cover the 20 watt load produced by my two 10 watt bulbs. Cost of the replacement was about $15.
7) Connected the replacement transformer to the hood power switch. Here, I had to be a little careful to maintain the original polarity of the wires from the switch. This is because the original transformer, though it had one white and one black wire on its 120v side, was attached to the switch via two identical-looking yellow wires, using a non-standard plastic connector. The new transformer did not have one of these connectors on its 120v input wires (black and white), and I wanted to make sure that the I wired the replacement exactly as the original had been wired. Fortunately, the original plastic connector ensured a consistent polarity. When I looked at the end of the connector, one lead was square and one lead was round and noted that the square lead had been attached to the White wire on the original transformer. The replacement transformer also had a white and black wire for its 120v side. So, I marked the yellow wire from switch that attached to the white wire through the square lead. Then, I cut off the plastic connector from the yellow wires, stripped the sheathing from them about 1/4 inch, and attached the white wire from the new transformer to the previously marked yellow wire, using a small wire nut. I then connected the black wire from the transformer to the remaining yellow wire in the same way.
8) On the 12v side of the transformer, the wires are the same color and I did not pay close attention to polarity, simply connecting each to the spliced wires leading to the halogen bulbs (that I exposed when I removed the wire nuts from them in step 4, above) using fresh wire nuts.
9) The double-stick tape that attached the original transformer to the hood remained firmly attached to the metal surface of the hood and it was still very tacky on the surface that had been attached to the original transformer. So, after I tidied up the wires in the space, I positioned the new transformer over the tape and pressed it down firmly, which seemed to adhere the new transformer to the hood pretty well.
10) With the connections completed, and power restored to the circuit at the breaker, the lights worked fine, and the fan continued to work fine. I reversed the steps I used to expose the switch and transformer.
So that's all there was to it. The cost of parts was about $20 for the transformer and a bag of wire nuts. Investigating the problem probably took more time than the actual repair, which took about 20 minutes from start to finish.