Specifications

Australian Monitor

Service Bulletin

AMIS Mixer Amplifiers

AMIS Booster Amplifier

Start-Up Issues in Extreme Cold Conditions

12 March 2012

age 1 of 1

Applicable Models

This bulletin applies to the AMIS250 and AMIS250P mo

els, and older versions of the AMIS60, AMIS120, AMIS120P,

AMIS120XL, AMIS1202P and AMIS480P models.

For Information Only

is bulletin is intended for service technicians only and is to be applied when presented with models exhibiting the

issue identified below.

Known Issue

In extreme cold conditions the models listed may not operate when turned on. A small number of reported instances

have been recorded in regions of extreme cold, typically when the unit temperature is less than 10ºC.

In some instances, the failure to start can lead to failure of the main bridge rectifier also.

This issue is limited to AMIS products using the Maxim MAX765CPA inverter IC.

The range of AMIS60 and AMIS120 models stopped using this part several years ago so this issue is limited to the

older models.

Identification

If you have one of the models listed above that has p

resented with the described issue then inspect the part fitted

(IC4) on the main amplifier board. If this part is a MAX765CPA then the cold start issue may be resolved by replacing

this part with a MAX765EPA part.

Later models are fitted with an LM2594 part that does not exhibit cold start issues.

Solution

An alternate part is available with wider operating t

emperature specifications.

The alternate part MAX765EPA is fully compatible with the original part MAX765CPA and may be exchanged if

required.

Replacement Wide Temperature Range Component

Temp. Range Package Maxim Part Mouser D

igikey

-40º to +85 º C DIP8 MAX765EPA 700-MAX765EPA MAX765EPA+-ND

otes

The MAX765 and LM2594 parts are not directly interchangeable.