Last week I received a question via email from reader Marshall Wilgard. It seems that he is having trouble with a Grandstream BT-200 desk phone.
For five years, I used a Grandstream BT-200 IP phone without any problems. Six weeks ago, a loud hum appeared on the phone as soon as I picked up the handset. About 10 days later, the hum vanished, for no apparent reason. However, about 10 days after that, the hum came back, for no apparent reason. Despite my rebooting the phone three times, the hum remained. Then approximately 10 days after the hum returned, it vanished again, for no apparent reason. My phone has had the latest firmware for more than a year, and my VoIP provider says the problem is not with it.
Hum like Marshal describes is usually an analog phenomenon, not something that I’d associate with firmware. It sounds to me like a problem with the hardware. Issues of hum tend to revolve around a problem with the power supply. Given the age of this phone I’d guess that most likely some kind of capacitor is failing.
In older style power supplies electrolytic capacitors were used to smooth the rectified AC current into steady DC power. Such capacitors are essentially metal foil plates separated by a layer of fluid. As they age the seals can degrade causing them to dry out, which makes them less effective at their task. Occasionally they can die dramatically, with a loud bang as their metal casing literally shoots off the circuit board.
The faulty part might be in the power supply itself. That would be nice, since you can try a new power supply quite easily and for very little cost.
It’s quite possible that the hum arises from a capacitor failing inside the phone itself. If that’s the case then I’d probably write off the phone. It’s simply too old to merit spending any money to repair.
Even if you’re handy with a soldering iron and can locate the bad component, there’s a significant chance that other capacitors will die as the phone continues to age. If the device in question was a classic, perhaps collectible audio power amplifier (I do admire older Carver and Phase Linear gear) then I’d make a project of swapping out all the electrolytic capacitors. In the case of the BT-200 there just isn’t much reason to make that kind of repair.
Whereas years ago SIP phones were costly, there are now quite a few models available for under $100. Grandstream have released many newer models, including the single line GXP-1100 that can be found for well under $50 . Aastra and Yealink also have some attractive, entry-level models.
Alternatively, if you’re not wed to the traditional desk phone form factor, you might consider one of the Gigaset SIP/DECT cordless phones. The entry-level Gigaset A510IP starts under $100 for a base and one handset.
No matter which make or model you choose, all of these newer phones outperform the BT-200 in every way imaginable.