Let's Make Robots!

Broken regulator on Dagu Red Back Spider

I was driving around with my Rover 5 (remote controlled) when it suddenly "stopped working". L1 (red led) kept on flashing. I pressed the reset button but nothing happened. I started taking it apart and I've come to the conclusion that the voltage regulator (LM2676) is broken. I've powered it straight from a lab power supply giving it 14V but the regulator only gives 3V. (measured on the regulator and the pins on the board) When I power it from USB it still works, then I measure 5V on the header pins and I can upload sketches. So I think the regulator is broken... Pretty strange as the regulator was not under a big load. It was only powering 1 9G servo.

Can I supply 5V straight to the VCC pins and bypass the regulator without further damaging it? I have a spare UBEC that I could use.

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DHL just came by my house. So now I have a new Red back spider and  a 2 DOF gripper. Shipping was indeed expensive but the parts were really cheap. I love DHL shipping from China to Belgium, most packages arrive in only a couple of days. Sometimes it's worth the money. I have a couple of days of, so now I can play some more with my Rover :)

I'm glad to hear everthing worked out well.

We do not normally sell direct to the customer but occasionally it is neccessary if there is no convenient distributor with the product in stock.

I've sent Claudia an email :)

I've checked all the pins of the regulator and both sides of the inductor. They all look good. I pushed on both components but they feel and look well seated on the pcb. I put 3 470µF caps between gnd and vcc and now I get 4V out of it when I supply 8V. If I supply more then 12V I get 5V out of it. I know switchmode regulators need decent circuitry to regulate, maybe I have blown up some component?

I think I better buy a new one. I'm interested in a couple of other Dagu products but the European suppliers seem to be out of stock. (a friend of mine wants a 4 channel motor controller and I would like to buy a 2 DOF gripper/arm with servos, the 21cm version) Could I buy these direct from Dagu and receive them in a timely fashion (DHL/UPS)?

You could order directly from Claudia if you want, the parts might be a bit cheaper but the cost of the courier service and (depending on your country) customs fees might be a killer.

Check the soldering on the regulator components carefully. Most likely you simply have a cracked solder joint. Sometimes the big components do not solder as well because they require more heat to get a good solder joint.

Chances are you just need to re-melt the inductor or regulator IC's solder joints.