Arcam A85 - Manual (Page 8)

A85, P85, P85/3 Service Guide
Build History
ECO
Number Date Description of Change
00_1089 02/10/00 A85 – Fascia position changed to prevent display buttons sticking
00_1129 01/11/00 A85, P85, P85/3 – Improved stability under heavy clipping of amplifier R345,
R346, R445, R446 changed from 100R to 0R link
C307, C308, C407, C408 changed from 47P to 100P capacitors
00_1138 27/11/00 A85, P85, P85/3 – C303, C304, C403 changed from 10uF to 100uf capacitors –
this prevents protection circuit from operating when driving a 4 ohm load at
low frequency
01_1030 23/02/01 A85, P85, P85/3 – RV300, RV400 changed to 220R presets to make it easier to
adjust the bias settings
01_1068 11/04/01 A85, P85, P85/3 – New output device clamp fitted to heatsink
01_1101 04/06/01 A85, P85, P85/3 – Sensitivity of DC offset detection circuit reduced – Power
amp cct R308, R408 changed to 22K - R314, R414 changed to 10K
PSU surface mount fuse F202 up rated from 500mA to 750mA
01_1142 22/08/01 A85 – Preamp board upgraded from L866 to L937
01_1178 12/10/01 A85, P85, P85/3 – Speaker terminals changed from Camcon to 4mm binding
post
01_E014 28/11/01 A85 – Preamp board fuses F300, F301 up rated to 2A surface mount
02_E033 31/01/02 A85 – Extra pad F038 fitted under TX to stop TX coming loose in transit
02_E035 04/02/02 A85, P85, P85/3 – Main 20mm fuse rating changed to 4AT
Software History
ECO
Number Date Version Description of Change
01_1072 18/04/01 1.1 Remote standby action changed from turning unit completely off
to putting unit into standby
01_1095 21/05/01 1.2 Delay added to start H8 start up routine (volume control chip)
01_1167 12/09/01 1.3 Volume chip read/write protocol changed
01_1179 26/10/01 2.0 Added the processor mode option
01_E011 23/11/01 2.1 Corrected the welcome message saving fault. This fault was
introduced with version 2.0 software
02_E048 15/02/02 2.2 Corrected the processor loop volume jump when v/c adjusted
Current Fuse Ratings (20/02/02)
Fuse Position Fuse Rating
Main Supply fuses - A85, P85, P85/3 2 x 4AT 20mm (Arcam part number C12406)
PSU fuse F202 - A85, P85, P85/3 750mA surface mount (Arcam part number C3751)
Preamp fuses F300, F301 – A85 2A surface mount (Arcam part number C3202)
Quiescent Current Setting
Left channel Measure points indicated on PCB -
Adjust RV300 for 8.5mV cold or 12 mV when warm
Right channel Measure points indicated on PCB -
Adjust RV400 for 8.5mV cold or 12 mV when warm