CAZ 2500

From Repair Wiki
Jump to navigation Jump to search

The internals of the EAW CAZ-series are nearly identical to the Alto Mac 2.2, Mac 2.3 and Mac 2.4 amplifiers. Alto Macro 830, 1400 and 2400 are also very similar. I figured this out by Googling the part numbers on the PCBs. Repair manuals and schematics for the Alto amplifiers are easily found if you look for them.

The alignment procedure in the service manual for the macro series is missing, however in the manual for the mac series the alinment and test section is present. I believe the procedure used in the mac series repair manual can be used also for the macro series amplifiers. I used the procedures to verify proper operation after completing my repairs.

Problem Solution

Amplifier turns on, but both channels are dead. Blown filter capacitors on one channel

Check and replace any blown fuses. In my case the main culprit was a bad connection on top of the board between −55 V from the rectifier board and its corresponding filter capacitor on the amplifier board. This results in reverse voltage across capacitor C222 which will cause it to short and spill its electrolyte. In my case connection was broken between E215 and C222 negative terminal as the leg of the capacitor had failed to make proper contact with the pad. Replace the blown capacitor (and any that look in bad condition) and add a wire underneath the board to ensure a good connection and properly solve the problem.

noisy or broken fans

replace with new. Sanyo Denki 9A0812S4021 is a suitable replacement that matches air flow of the original part, with the benefit of a lower noise level.

fans running slow or not at all

This week I came across a unit where I noticed the front fan was barely spinning. It was very worn and I replaced it, but the new one was also barely spinning. Turns out the fan was not receiving proper voltage due to a bad electrolytic capacitor. This in turn has caused the unit to run hot and almost all electrolytic capacitors were out of spec and had to be replaced. Only reasonable thing to do was replace all electrolytes except the 8 large ones which were still within spec. This solved the issue and probably a few others that we were not yet aware of.

Credit[edit source]

Original article credit: AMelbye