Dave's Rave: New Circuit Boards for OEC C-arms


Hey, gang, Dave here at RSTI with some news on updated circuit boards that you are likely to see in the OEC 9800 and 9900 C-arms. The three boards we will be covering today are the Generator Driver PCB, the IGBT Snubber PCB and the Battery Charger PCB. 

The new boards were made necessary due to some components becoming obsolete. It’s difficult to make new boards when they stop making the parts you used before! Therefore any replacements ordered from the manufacturer will be the updated PCBs.

The new Generator Driver PCB and IGBT Snubber PCB are easy to distinguish from the old version primarily because the board itself is now blue in color as opposed to the traditional green. They are both direct replacements so you will still use the same connectors (no changes to the wiring harness). The test points used for dead-time adjustment still have the same designations ,and are in the same order, TP70, TP66, TP67 and TP68; however the minimum allowable dead-time has dropped to an impressive 1uS from the previous 1.5uS. The test points are also now in a single row near the center of the board, just above the large heat sink. 

The battery charger is a bit different in several ways. It looks similar to the old version, though the inductor (largest component on the board) is now closer to the top edge. There are now three green LEDs along the bottom edge of the board that indicate the mode of the battery charger: 

// One LED = Low Charge Mode 
// Two LEDs = Normal Charge Mode 
// Three LEDs = Charge Boost Mode 

The amber current display is near its old location, but the current values have changed by a factor of 10X. Whereas a reading of 25 would be equal to 25 mA on the old charger board, it is equal to 250 mA on the new one.

The red voltage display is still with us as well, ranging from 160V to 250V, with the big difference from the old board being that now all of the voltage LEDs up to and including the charge voltage will be lit. Calibration of the display remains the same in methodology, though the adjustment pots have changed. Pot R144 is now the voltage adjustment and pot 147 is the display adjustment.

Be aware that the new charger board has a different wiring harness. This means that an old version board will require the old wiring harness in order to replace the new version board. 

For more information, our next OEC 9800/9900 class is scheduled FOR November 9 – 20. 

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