Specifications

Section 4 — Circuit Description and Repair
4.1 Circuit Description
The first two sections of U1 are balanced audio input stages of the "A" and "B" audio inputs. Overall, these have a
gain of 0.33 (loss). The next stage combines the two channels and has a gain of 10. Capacitors C1 through C12
provide high frequency roll-off and RFI immunity. A rectifier, short term integrator (about 1 second), and comparator
follow. When audio is present, the "Audio" LED is turned on by this comparator. U2 is a small microcontroller that
receives a logic-level signal from the audio comparitor. The microcontroller performs the timing functions and
controls the output peripheral components (LED’s, relay, audible alert).
4.2 Factory Service Policy
These policies are effective August 1999 and are subject to change without prior notice.
4.2.1 Factory Warranty
Sine Systems, Inc. guarantees our products to be free from manufacturing defect for a period of one year from the
original date of purchase from Sine Systems, Inc. This warranty covers the parts and labor necessary to repair the
product to factory specifications. This warranty does not cover damage by lightning, normal wear, misuse, neglect,
improper installation, failure to follow instructions, accidents, alterations, unauthorized repair, damage during transit,
fire, flood, tornado, hurricane or acts of God and/or nature.
4.2.2 Factory Return Policy
The factory return policy only applies to equipment purchased directly from Sine Systems, Inc. Equipment
purchased through a third party (dealer) is subject to the return policy of the dealer and arrangements for return or
exchange must be handled through the dealer.
Sine Systems policy on returns and exchanges with the factory is broken down according to the following schedule:
30 days “no questions asked”
During the first thirty days from the date that equipment ships from our factory we will accept it
back for a full refund less shipping charges provided that the equipment is still in new, resellable
condition with no cosmetic damage. This does not constitute an evaluation program. It is for
legitimate purchases only.
less than 60 days, may be returned less 15% restocking fee
Between 31 and 60 days from the time we ship the equipment, we will accept unmodified equipment
back for a refund less shipping charges and 15% of the invoice cost. This is to cover the cost of
restocking the items which must then be sold at a discount as reconditioned instead of new.
no return after 60 days
We will recondition the equipment for you according to our repair rates but we will not accept it for
refund or exchange after 60 days from the initial purchase.
AFS-3 Circuit Description and Repair page 4.1