Power Modules: Gen 1 or 2?
Identifying Your Subwoofer’s Power Module
Q: “How can I tell what generation board I have in my subwoofer?”
A: One cannot tell by the serial number or just by looking at the assembled subwoofer alone. The power module must be removed to identify whether a Generation 1 or Generation 2 circuit board is installed. This will determine if only the power module can be sent to Entec Subwoofer Service (E.S.S.) or if the entire subwoofer needs to be shipped.
Below are pictures of each board to help identify what’s installed in your Entec:
Unplug power cord. Remove the 8 screws holding the power module to the cabinet and carefully slide out to reveal the circuit board. Be careful not to disconnect the wiring or pinch it when re-installing the power module. Board color may vary.
Entire subwoofer must be sent.
Note four blue (or red) adjustment pots in upper corner (arrow).
Module alone can be sent.
Note lo-pass select switch (arrow).
A common issue with Generation 2 circuit boards:
Heat:
There isn’t a heat problem on Generation 1 circuit boards. However, on Generation 2 boards the board mounted power transistors and resistors can run at oven temperatures to the point of melting solder, causing components to fail, and slowly (and permanently) burning the circuit board. The photo to the right of the burned Gen 2 board is the result of over twenty years of regular use on one pair of Entec L2-F20 subs.
Thus far, every Generation 2 board that’s come through the door has had heat damage to the circuit board. Many folks leave these units powered 24 / 7 / 365 and this can take a toll as the power modules tend to run from very warm all the way to board burning, solder-melting hot. While the engineers did a great job designing these audiophile subwoofers loved by many throughout the world, some updating, like the JRS heat modification, greatly diminishes the possibility of further damage to the circuit board.
When the heat mod is performed, every single board mounted power supply component is replaced with new selected components and the heat generating issues are eliminated. Heat damaged paths are repaired and a conformal coating is applied to the board. When all is said and done, over 500 non-solder, de-solder and re-solder connections may be performed.
Q: What does the JRS overhaul process consist of?