Service Bulletin - YORKVILLE AP 6020 Service Manual

Yorkville Sound Yorkville Sound Yorkville Sound Yorkville Sound
550 Granite Court
Pickering, Ontario
Canada L1W 3Y8
Date Date : : : : February 29, 2000 Date Date
Re Re Re Re : : : : AP6020 / AP6040 Internal Fuse Problem
Dear Staff & Dealers,
We are sorry to advise that a service issue has developed with the AP6020 and AP6040 power
amplifiers that will eventually affect every unit shipped before February 26th, 2000. All units in
stock in Canada and the USA have been reworked to correct this problem.
The problem is serious enough that it is necessary to modify all units in the field, so we are here
by issuing a service bulletin that will be followed up with letters and phone calls to all affected
dealers and distributors.
All units should be modified as soon as possible. The units can either be returned to Yorkville for
modification, or can easily be modified in the field by a qualified service technician. We will, of
course, accept warranty claims for this modification.
Required Modification:
--------------------------------
- Remove the lid from the unit and both power amp boards.
- Locate the small 0.1A fuse on lower power supply board (#M1151 - AP6040 or M1177 -
AP6020). This is the only fuse in the unit.
- Replace this fuse with a 5W 390R resistor (YSL Part#4736).
- Dress all wires away from the two 5W 390R resistors.
- In order to be sure that no damage was done to the upper power amp boards when they were
removed it is strongly advised that the technician carefully retouch the solder on the three legs
of each of the following transistors: #Q32A,Q32B,Q33A and Q33B on each of the two power
amp boards (AP6040 - M1176/M1176A, AP6020 - M1150/M1150A)
- Replace the upper boards and lid.
Sorry for any inconvenience caused as a result of this problem. For further technical information
or assistance please contact Peter Mourtos at Yorkville Sound via phone at (905)837-8550
Ext.218 or via email at pmourtos@yorkville.com .
Enclosed - Layouts for AP6020/AP6040 Power Supply and Power Amplifier boards. Enclosed
Enclosed Enclosed

SERVICE BULLETIN

Phone: (905)837-8550 Ext.218
Fax: (905)839-5776
Email: pmourtos@yorkville.com
www.yorkville.com