New Delphi CS130D Design Change Released From Transpo’s Rebuilder’s Forum Delphi Automotive has instituted a design change to their regulators utiliz- ing a new internal circuit layout. This regulator series is used on late model CS130D style alternators and can be identified by the regulator’s model number stamped on the regulator’s side as a 77XX number. Internally, this series uses a mono- lithic chip that incorporates all power, voltage reference, and logic circuitry connected to a satellite printed circuit board that contains discrete surface mounted film capacitors. All four units can be activated by applying 12V and ground to the marked terminals and connecting the L terminal through a 12V, 100mA bulb back to the 12V source. At this time the bulb will ignite. Caution, do not connect the L termi- nal directly to the 12V source, as this will destroy the regulator circuit and components. The D719 and D734 incorporate an internal resistor from the L to the F/ I terminal, making these I terminal type. This resistor effectively replaces the bulb and will be activated by applying 12V directly to the I terminal. The bulb also serves as the warning lamp and should be used in lieu of the I terminal when testing. The D729 and D734 use the F/I terminal as an output and the wave- form is identical to the alternator F+ terminal, but the resistor is external and isolated in the vehicle connector for PCM regulation. The D719 and D748 have a short delay for LRC while the D729 and D734 have a longer delay time. Compared to the older Delco DIF circuit package equivalents there are several differences in performance. The older Delco circuits require a small standby current where the new design is deactivated. The 2 mA difference in these designs would discharge a typi- cal 80 amp hour battery in several years; the internal leakage of the bat- tery far exceeds this value. Another difference is that the set- point voltage no longer cuts off the soft start voltage in the new Delphi series. The switchover from remote to local sense has been increased from 5 to 8 volts. Regardless of this trip voltage, any remote sense less than sense point will force fail-safe mode which may be a result of the internal reference volt- ages of the new monolithic chip. The crossover frequency for enabling the under-voltage lamp has been increased in the new chip, meaning the engine will have to be in a higher idle condition before the under-voltage lamp is ig- nited. This may prevent the warning lamp from igniting at extended idle al- though the battery is still being pulled down to 11.0 volts. MAY, 2000 Page 1 of 1