JBL LSR28P Technical & Service Manual

Also see for LSR28P: Owner's manual

26TROUBLESHOOTING GUIDEThe purpose of the troubleshooting guide is twofold.First, this guide will enable the service technician to become familiar with the operatingcharacteristics of the unit and to accurately diagnose and repair the associated symptoms thatindicate malfunctioning circuitry. Secondarily, this guide will help the technician to decrease thetotal repair time needed to correct faulty circuitry by improving his/her troubleshooting skillsand ,thus, increasing the profitability of the service department.The actual electronic repair process can be separated into two components, which determinethe total repair time—diagnoses of the problem and repair of the problem.. The repair time of theequipment will vary minutely, but, statistically it will be consistent, therefore, it is alreadydefined as a specific amount of time. The only other factor that can impact the total repair time isthe diagnoses time. By becoming familiar with the operation of the equipment, its design faultsand attributes, one’s skill at diagnosing the symptoms of faulty circuitry will increase over time.And, thus, the diagnosis time will decrease.Since the old adage of “time is money” is very apropos in all societies, so it is withelectronic repair. The technician, therefore, must be time efficient with respect to diagnosing andrepairing equipment.• Visually inspect product. Many times a customer's problem with a unit can be located just byvisually inspecting the product for gross faults. This visual inspection can also determine ifthe equipment has been abused when a claim for warranty service is involved.• Verify the fault that the customer is experiencing. If unable to reproduce the customer'scomplaint, notify the customer of your findings and obtain more information about thecomplaint.• Verify complaint and repair product as necessary if in product is eligible for in warrantystatus.• If product is out of warranty, contact the customer with an estimate of the repair charges.Note: It is the policy of JBL Professional to always give the customer "the benefit of doubt"concerning decisions of eligibility of warranty coverage. This not only is a good businesspractice in the long run but also promotes customer good faith and satisfaction.Wait for approval or denial of estimate and note the time and date of customer's decision.• If customer approves, repair unit and verify proper operation• If customer denies, wrap up set and returns to same.If at all possible perform a Safety Checkout before returning set to customer regardless if unit isrepaired or not.