A Warning for Owners of Furman IT Refernence 20i


A Warning to anyone who owns a Furman IT Reference 20i for power filtering-
Do Not Leave the unit unattended while powered on. A few weeks ago, I smelled the very acrid smell of melting plastic and circuit board coming from my stereo. Long story short, my Furman IT Reference was the source and one of the circuit boards that was designed to prevent ‘current inrush’ self destructed. 
Thankfully, I was close by and was able to quickly unplug the unit or there was a very serious chance of fire! Since then I have tried, without any success, to have the unit repaired, but have gotten nowhere with Furman (now part of Nortek). I have tried sending in multiple requests for service. I’ve tried calling, only to end up in ‘press 1 for, press 2, purgatory..‘. When I have managed to get someone on the line, they referred me to their ‘dealer network’ for repairs. I contacted one of the dealers and they told me that only Furman is allowed to perform their own repairs. Call back Nortek and they won’t sell parts and they only use their dealers for repairs. Lather, Rinse, repeat. For $5k I’d expected better. The only good news is that I’m a very experienced service person for research instrumentation and I was able to identify the electrical component that failed (Ametek Thermistor SL22). Furman undersized the thermistor in their inrush circuit and thereby started the board to self destruct. The part is very cheap and I’m hoping I can still salvage the circuit board. But BEWARE! Had I not been nearby, it could have been much much worse!!!

mbachemist

I do want to say a few things:

1 - I’ve had my Elite 15i for like 20 years. Never ever had a problem with it.

2 - The part in question seems correct for the load, maybe the built-in transformer however makes it undersized?

3 - The metal housing makes a fire very unlikely.

4 - The person who answered the phone at Furman was very helpful and straightforward about how things work now, if you got into a voice-mail merry go round with them I sure did not. I mean, I didn’t get the answers I wanted but it was all pretty straightforward.

 

Thanks so much for the information. I really do appreciate it! 
For whatever it’s worth (and after 40 some years of working with research instrumentation , I know this part is boring), their toroidal transformer is one of the largest I’ve yet seen in high end audio, bigger than what I’ve seen inside of big Krells or even the big Boulder amps. While toroidal transformers are well recognized for their low stray fields, it comes with a cost- serious ‘inrush current’ till the AC field is stabile. A very common approach to handling inrush is to place a thermistor in front of the transformer. Upon startup, the thermistor (dependent on type) appears as a high resistive load. That load is then dissipated as heat. Unfortunately, in this case, the heavy gauge wires carrying the AC load were run over the top of the thermistor. As the thermistor was overheating the circuit board traces, it was also melting through the load wires and would have eventually fused the wires together likely creating a ‘dead short’ to the metal chassis. The unit has a circuit breaker, as does the main panel to my house. But, after decades of working inside of instrumentation, I believe it’s always best not to ‘tempt the gods’. Never turning off the unit would definitely reduce the amount of ‘thermal cycling’ that the thermistor sees and extends its MTBF (Mean Time Before Failure- old term). I strongly recommend Not leaving electrical equipment powered on. 

If you are not getting a satisfactory response from the manufacture, I would threaten to take the issue up with electronic safety board in your country of residence?  If the unit has a known issue that could cause a fire, you would think that the manufacture would not want to risk the liability.  

Just wow. I appreciate the accurate description of what has occurred, an NO, few of us here would find your explanation boring. In fact, I am always interested in the guts of a unit. Interesting to note the size of the transformer in particular. It's one thing to get the correct sized thermistor to do the job but running a line over the top of it speaks for itself. Please do keep us informed as things hopefully progress. 

Owned a 15i Elite for years and it functioned flawlessly.  Replaced with Decware ZLC which smoked (figuratively) it completely.  The ZLC made everything much quieter and more dynamic.  So, in a weird way, perhaps the smoked unit did you a favor and you can move on to a better unit.  Cheers