Premature Operation Of The Thermal Protection Circuit; Fault Symptoms - Cyrus 6 Service Manual

TECHNICAL BULLETIN
Number 29
PRODUCT:
SUBJECT:

Premature operation of the thermal protection circuit

INTRODUCTION
The thermal protection circuit of the Cyrus 6 and Cyrus 8 may activate early at too low a temperature, causing the
amplifier to cut out.

FAULT SYMPTOMS

When playing music at higher levels, the amplifier may cut out. This is most likely to happen after a period of 10
to 20 minutes, when the heatsinks have warmed up.
WHEN TO APPLY THIS CHANGE
Cyrus 6: only units returned for reports of premature operation of the thermal protection circuit should have this
modification carried out.
Cyrus 8: the change should be carried on all units returned for service.
MODIFICATION required
The following changes should be made to the main PCB:
Location
R314
R315
please note
This change has been implemented during production since August 2003, from the following serial numbers:
Product
Cyrus 6 (black)
Cyrus 6 (silver)
Cyrus 8 (black)
Cyrus 8 (silver)
CYRUS 6 & 8 – PCB parts list
Cyrus 6, Cyrus 8
original part
100k ohm
100k ohm
Serial number
CEN00278
CENS0438
CEP00438
CEPS0799
change to
22k ohm
22k ohm
26 Jan 2006