Hi, In case there are BEE2 users who don't follow the BEE2 mailing lists...
Matt Dexter ---------- Forwarded message ---------- Date: Mon, 5 Mar 2012 16:56:46 -0800 (PST) From: Matt Dexter <[email protected]> To: BEE2 Users <[email protected]> Cc: [email protected] Subject: Re: [bee2-users] BEE2 with a misbehaving internal PSU Hi, It turns out we've had two BEE2s with the same sort of power supply related problem. The tin plating on the Molex connectors for the 5VDC, GND inlet power had failed. I'm not sure what the most accurate technical term is for the damage but the contacts had turned from bright glossy silver mirror like surfaces to very dull grey colored. Curiously, on both BEE2s the plating of the ground lead contacts was significantly more damaged than the plating of the 5V contacts. As a short term temporary fix, while we ordered replacement parts, we used a fine emory cloth to gently buff the contacts, then cleaned them with alcohol and then re-mated the contacts. The connections will be redone entirely the next chance we can schedule downtime in our system. So far this kludge repair was worked for over a week without problems; even so we'll do the full repair asap. For the other board we had the time to buy and install new Molex 42819-2232 2 pin vertical headers for the PCB side and Molex 42816-0212 housing and Molex 42815-0031-C terminals for the copper wires. We cut off the old terminals and thus the wires from the PSU are shorter but there was enough spare cable so this wasn't a problem. This repair requires removing the BEE2 PCB from the chassis but in the end wasn't all that difficult. If anyone else has experienced similar or other BEE2 PSU issues I'd appreciate hearing the details. Matt Dexter On Wed, 15 Feb 2012, Matt Dexter wrote:
Hi all, I hope someone will be able to help me with repair one of my BEE2 internal power supply units. Debugging will continue tomorrow when I can get my hands on the PSU. In preparation for tomorrow if you have experience debugging similar sorts of issues with the BEE2s internal PSUs your suggestions would be welcome. The BEE2 and PSU had been working in the field for just over 3 years and then started to shutdown randomly. A fellow engineer has taken lead on testing and reports... 1) on initial power up, with operational gateware, the DC voltage is a little low at ~ 4.7VDC 2) the PSU was removed from the chassis and no glaring faults were found. 3) Using high wattage resistors connected to the PSU, not PCB, the PSU shutdown at 25 Amps and even 12.5 Amps. At 8 Amps the PSU output held stable at 4.93 V Other notes: The PSU has been powered by 120 VAC 60 Hz supply only. The PSU and BEE2 have been running in pretty benign environments with plenty of airflow and ambient temperatures typically near 70 degF and maximum for short periods of time of 80 degF. Thanks, Matt Dexter
