Beyond 2000 Plus – The Teardown – Part 2 – PCB and Components

Take a look here for the motivation behind this project, and here for the first part of the teardown.

Possible H-Bridge?I could see clearly, even before I opened it up, what looked like 4 transistors on the outer two sides of the control section of the Beyond 2000+ and instantly suspected a dual H-bridge design.  I figured with the complexity of the ‘modes’ the whole thing would be powered by some kind of microcontroller.  Exploring how the microcontroller in the Beyond 2000 Plus controlled the h-bridge to drive the motors and also how it drove the LED display seemed a worthwhile endevour.  A group of people, smarter than I am, most likely spent a great deal of time designing how this thing was going to work and if I’m going to try to replicate it, I will probably gain some useful info from their finished product.

Beyond 2000+ TransistorsTrue enough, the circuit design powering the motors was a dual H-Bridge with the 2 sets of 4 transistors lining the edge of the board.   Transistors are PNP and NPN silicon power transistors: B772 and D882 respectively.  Datasheets: NEC B772 , NEC B882

little diodesLooks like they have 4 catch-diodes to deal with voltage spikes from the motors.  These are very common small signal diodes, possibly 1N4148.  These can handle current up to 200mA, which seems kinda small for the motors we’re using and the spikes that could be expected.   This may be why it would shut off periodically.Beyond 2000+ Board Layout

Notice the 16V 470μF electrolytic capacitor?  Assuming this is to help smooth out voltage drops when the motors run.

microcontrolloerThe microcontroller is labeled “Pilot Boat” and “PB35 0301”.  I couldn’t find any information on it online, I’m assuming it’s not custom, but I haven’t sniffed out what it is exactly.  It’s a 28pin SMD design.

The motors run at different speeds, so there is obviously some kind of PWM at play here.

LED ArrayThe LED array seems to be arranged in a matrix display requiring what I think is only 8 pins to control the 16 LEDs.  Some kind of ‘plexing going on here.

Motors are the simple brushed DC type and have been measured to run peak at 1A for the vibration motor and a little less for the shaft motor.  Neither motor has a filter capacitor attached.

Batteries are 4 AA cells in series producing 5-6v of power depending on type and charge.

There seems to be no voltage regulation whatsoever, so everything runs straight off the batteries.Buttons and LED Matrix

Buttons are that rubber type material found on many remote controls and have conductive circle backings that bridge exposed PCB traces.

The next installment will take what I’ve learned here to help design an home-brew solution.  Stay tuned…

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