Hi
I've been struggling with the Alpine 3544 amplifier for some time.
It started with damaged power transistors. I was replacing them, being aware that the problem could be in the controlling degree (originals from disassembly). The upc1298V (IC 502) has failed (short circuit). I checked its surroundings and swapped upc layouts to make sure one was a problem. The diagnosis was correct and I replaced upc1298V.
Idle current set:
In the place where the old and functional upc1298V system was located, the millivoltmeter showed 0mV in TP5 and TP6 measuring points. In points TP3 and TP4 the voltage was within 3.5mV - quite correct. Soon after, the old upc1298 chip, installed in place of the previously damaged chip (IC502), also fell short.
I measured the voltages on the upc1298v systems and the measurements were consistent with the table in the service manual. The greatest deviations up to 1V.
I am puzzled by the high operating temperature of the upc control chips. Without any load and input signal, they had 55 degrees Celsius with the housing open after 2 minutes of operation. According to the table with voltage measurements (supply voltage 14.4V) on pins 9 and 10 of the PWM driver upc494 should be 267mV, and in my case it was about 5.3V on both pins (D801 and D802 removed).
Any of you repaired such an amplifier and had similar problems?
I've been struggling with the Alpine 3544 amplifier for some time.
It started with damaged power transistors. I was replacing them, being aware that the problem could be in the controlling degree (originals from disassembly). The upc1298V (IC 502) has failed (short circuit). I checked its surroundings and swapped upc layouts to make sure one was a problem. The diagnosis was correct and I replaced upc1298V.
Idle current set:
In the place where the old and functional upc1298V system was located, the millivoltmeter showed 0mV in TP5 and TP6 measuring points. In points TP3 and TP4 the voltage was within 3.5mV - quite correct. Soon after, the old upc1298 chip, installed in place of the previously damaged chip (IC502), also fell short.
I measured the voltages on the upc1298v systems and the measurements were consistent with the table in the service manual. The greatest deviations up to 1V.
I am puzzled by the high operating temperature of the upc control chips. Without any load and input signal, they had 55 degrees Celsius with the housing open after 2 minutes of operation. According to the table with voltage measurements (supply voltage 14.4V) on pins 9 and 10 of the PWM driver upc494 should be 267mV, and in my case it was about 5.3V on both pins (D801 and D802 removed).
Any of you repaired such an amplifier and had similar problems?
Last edited:
