Fujitsu General Australia

As problem of title, I have received the problem report from quality assurance department.

I would like to inform about problem report detail.

• Problem detail
  Product ; V series Cassette model
  Problem contents ;
  Transmission error was occurred. on the main PCB, there was the trace of damage by heat.

 Analysis result

1) Analysis of sample unit.

the Q2 transistor on the switching power circuit had been burnout.

And more, there were some failure at the parts on the switching power circuit like below.

As the result, transmission error was occurred, because, DC power did not supply for main microcomputer.

• Speculation of this result’s cause
  FGL found that there is the case that temperature of R5 resistor become increase more than design criteria’s value.(*1)
  So, R5’s resistance value became to drop more than expected. Then current flowed more than expected.
  As the result, some failure at the parts on the switching power circuit was occurred.
  
  (*1)
  As to Cassette model, PCB is installed for downward direction. Therefore, heat is apt to be confined.
  So, if product is stopping , and VRF system is operating by heating mode, temperature of R5 increased more than design criteria’s value.

• 
  
  FGL checked the case of small cassette model. but, the increasing temperature value was less 20K than Cassette model .
  Therefore, FGL think same problem was not occurred case of compact cassette.

• Measure
  By circumstances of procurement, production company of R5 resistor was changed from August 2011.
  (from Rome to YAMAKA electric)
  As to R5 resistor specification of YAMAKA’s one, derating specification is higher+15K than Rome’s one.
  FGL checked by using actual unit YAMAKA’s R5 resistor installed. As the result, problem did not occur.
  Therefore, FGL think that this problem don’t occur if YAMAKA’s R5 resistor is used to main PCB.

 Measure to product

Already installed product;

Measures by each location if problem is occur.

As to changing PCB, please use the spare parts that manufactured date is after August 2011.

As to cost, parts cost itself will payed by FGL. But, Range of warranty shall meet the following conditions.

1. The case that problem occurred within 10 years from installed date.

2. The case that burnout point was identified at Q2.

3. The sales area are only FG AUST, FG EURO and FGEF.

*confirmation method of manufactured date
you can confirm it by label on the PCB.(This case 061130 means manufactured date is 30^th November 2006)