Home |
Search |
Today's Posts |
|
Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
Posted to sci.electronics.repair
|
|||
|
|||
HP/Agilent E3632A programmable power supply has power up failure (solution)
The schematic located in the service manual for this power supply has a
logic error: on page 128 (BIAS SUPPLY) it shows that U11 pin 1 (DELAY) is connected to the micro's reset pin. This is incorrect. U11 pin 5 (RESET) should be connected to the micro's reset pin. I have verified that this error also exists in my power supply - it is mis-wired/routed. I've re-worked my power supply to correct the issue when it had stopped working, but the LM2925T's RESET output does not drive to a proper logic 1. It only gets to about 2 volts. The problem is that the LM2925T's internal pull-up is only 30K. Since it is driving a 80196 as well as an ASIC, this was not quite good enough. Solution: I added an external 4.7K resistor to the micro's reset line. The power supply is now operational. |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Sump Pump , whats my best solution for power failure | Home Repair | |||
PC Power Supply Failure | Electronics | |||
pc power supply failure? | Electronics Repair | |||
Switching Power Supply Failure | Electronics Repair | |||
Switching Power Supply Failure | Home Repair |