Transpo Tech Tips From Transpo’s Rebuilders Forum Thermally conductive heat transfer grease is vital to enhance the life ofa rectifier. Essentially, this grease accel- erates heat transfer thereby maintain- ing a moderate operating temperature for the heatsink. Hence, the diode op- erating temperature is maintained lower. A “thin” layer of grease will quickly transfer the heat from the nega- tive diode plate to the SRE housing. (Thick applications can cause undue stress on the negative heatsink during installation.) Proper grounding is essential in all electrical circuits and especially impor- tant in alternator installation. Improper grounds can negate proper clamping of avalanche voltage which destroys the diodes and vehicle electronics, as well as failing to complete the rotor field circuit causing regulator failure and re- stricting the ability to produce proper output. Poor grounds can also cause EMI and RFI interference causing electronic noise that creates false read- ings from sensors, regulators and other electronic circuits. Use caution when testing the P-D plug connection on a 1998 or 1999 Mazda Protégé. These models with Mitsubishi alternator A2TB0091, Lester 13718, feature a P-D vehicle plug. The unique P-D regulator uses “P”’ phase (stator signal) and “D” drive (a low input voltage) to enable the PCM to control the alternator. Be careful when installing and testing cores to avoid damaging the regulator circuit with too high a voltage across either the P or D terminal. Use digital volt ohmmeter set on DC voltage and at- tach the negative lead to the positive terminal on the alternator. Measuring the P terminal with the positive lead will read between .9 to 1.1 volts. Mea- suring the D terminal with the positive lead, 0.5 to 0.7 volts. An S-L type unit will measure considerably higher volt- age. Rotor conditions can affect an alternator’s output and performance. Small diameter wire with too few turns creates the same electrical amperage draw and ohm value as the OE wind- ings; however, the smaller wire will have fewer turns and decrease the amperage turn performance. Too large of a diameter wire and too few turns creates high amp draw or a hot rotor. This may increase high-end output but will stress the regulator and destroy low-end performance and lead to pre- mature failure. Customer complaint: You have just replaced the alternator, and the charge and brake warning lights stay on all the time, yet the charging voltage is cor- rect at 14.6 volts. Sound familiar? If the application is a Toyota 4-Runner or pickup that uses a Nippondenso alternator like the 14182 (021000- 6000) or similar the most likely prob- lem is the “charge light relay.” If the original regulator fails ina high voltage condition this relay can be damaged and cause the symptoms listed above. Customer uses VRC101-27 to determine the required turn on lamp voltage in order to separate regulators. “Your diagram shows wiring the VRC101-27 and the regulator directly to the tester; but I used it with the test fixture. Using jumpers, I connected the VRC101-27 between the tester and the regulator fixture. B+ and B- con- nected to both the VRC101-27 and the regulator fixture. Instead of con- JANUARY, 2001 necting the lamp test lead to the tester (12-volt lamp) I connected the regu- lator lamp test lead to the VRC101- 27 1-volt connector. This works on all of the samples that I have.” be TRIE] Page 1 of 1