Mackie-Acoustics8BUS-mix-sb1 维修电路原理图.pdf

SR408 rework instructions SSE Oct 2000SR40-8rework.pdf, page 1 of 4SR408 and SR568 rework instructionsModels affected:SR408 and SR568Symptom:Various failuresPossible Cause:Susceptability of the mixers to static discharge and power spikes.Solution:Rework the circuit boards by adding bypass capacitors and associated components in various locations.Safety Warning:Caution! These instructions are for use by qualified personnel only. To avoid electric shock, do not per-form any servicing unless you are qualified to do so. Refer all service to qualified personnel.Boards to be reworked:1Brain board assembly055-169-002Output digital board055-101-003Mono channel boards055-067-004Stereo channel board055-071-005Master output board055-074-00Tools Required:Phillips head screwdriver, 1/16” Allen wrench, needle nose pliers, electrical cutters, soldering iron, solder,safety glasses, RTV silicone adhesive (electronic grade to secure cables), 3 loaves of bread and a Frenchmaids outfit.ESD Warning:Caution! Each board should be treated and repaired using ESD precautions.Preliminary:The rework involves removing most of the circuit boards, so the top and bottom of the console must beaccessable.Procedure:1.Remove all cords (including the power cable and input cable) from the console.2Remove the bottom from the console to expose the boards to be removed.The pages which follow show the rework required on each board.RadioFans.CN 收音机爱 好者资料库? ? ? ? ? ? ? ?SR408 rework instructions SSE Oct 2000SR40-8rework.pdf, page 2 of 4Rework procedure for the Brain board 055-169-00:The Brain board and the output digital boardare both mounted to the stiffener inside theconsole.1.Make a note of the placement and direc-tion of all cables to these boards, thenremove the Brain board by undoing thefour screws.2.Add a 0.1uF capacitor acrossPin 1 (+5VDC) and Pin 2 (GND )of the voltage regulator (U10).3.Add a 0.01uF capacitor between Pin 2(GND ) and chassis ground (stand-off). Usea solder lug (not shown).4.Add a 0.1uF capacitor across connectorJ2-pin 3 (+5VDC) and J2-pin 2 (digitalground).5.Add a 0.01uF capacitor between J2-pin 2(digital ground) and chassis ground (stand-off). Use a solder lug (not shown).5.Add two 10k, 1/8th Watt pull-up resistorsacross the Eprom devices:U11-pin 8 to U11-pin 5,and across U9-pin 8 to U9-pin 5. (Vcc andSDA).RadioFans.CN 收音机爱 好者资料库? ? ? ? ? ? ? ?SR408 rework instructions SSE Oct 2000SR40-8rework.pdf, page 3 of 4Rework procedure for the Output Digital board 055-101-00:1.Make a note of the placement and direc-tion of all cables to the Output Digitalboard, then remove it by undoing thescrews.2.Add a 0.1uF capacitor across connectorJ1-pin 3 (+5VDC) and J1-pin 2 (digitalground).Rework procedure for each Mono Channel board 055-067-00:1.Remove the cables from the back of themono channel 1-8 board.2.Using a 1/16” Allen wrench, remove the 15button head screws from the top surfaceof the console, for channels 1-8.3.Move the board back slightly and gentlyremove the cables running from thechannel board to the mono pod, andremove the board.4.Add a 0.1uF capacitor across connectorJ7-pin 14 (+5VDC) and J7-pin 13 (digitalground).5.Add a 0.01uF capacitor betweenJ7-pin 13 (digital ground) and chassisground (stand-off). Note the use of a solderlug is recommended, as shown.6.Repeat for all remaining mono channelboards.? ? ? ? ? ? ? ?Rework procedure for the Stereo Channel board 055-071-00:1.Remove the cables from the back of thestereo channel board.2.Using a 1/16” Allen wrench, remove the 10button head screws from the top surfaceof the console.3.Move the board back slightly, and gentlyremove the cable running to the masterpod and the cable running to the mastermeter, and then remove the board.4.Add a 0.1uF capacitor across connectorJ7-pin 14 (+5VDC) and J7-pin 13 (digitalground).5.Add a 0.01uF capacitor between J7-pin 13(digital ground) and chassis ground (stand-off). Note the use of a solder lug is recom-mended.Rework procedure for the Master Output board 055-074-00:1.Remove the cables from the back of theMaster output board, paying particularattention to where they connect to andtheir direction.2.Using a 1/16” Allen wrench, remove the 23button head screws from the top surfaceof the console.3.Move the board back slightly, and gentlyremove the two cables running to themaster pod, and then remove the board.4.Add a 0.1uF capacitor across connectorJ18-pin 2 (+5VDC) and J18-pin 1 (digitalground). This is located along the bottomedge of the board, and the cap can beadded on the component side.Finishing up:1.Before reinstalling the boards into theconsole, clean the metal chassis surfacewhere the standoffs (chassis ground) willmake contact. Clean off any paint, oxida-tion, or any other contamination.2.Re-install all cables and secure the connec-tions with silicone RTV to ensure the cablesdont come loose.3.Perform a complete specification andsafety test before returning the console toyour customer.SR408 rework instructions SSE Oct 2000SR40-8rework.pdf, page 4 of 4