Arcam A85 User 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