AltecLansing-1556A-int-sch维修电路原理图.pdf

SPECIFICATIONS Input: a. Aux: Pin jack for AM/FAA radio tuner, tape machine, etc. b. Phono: Pin jack for record player (ceramic pickup). c. Microphone: Phone jack for high impedance microphone. d. Speaker - Microphone for inter communication. Input Sensitivity: a. Aux: 600 mv b. Phono: 600 mv c. Mic: 8.2 mv d. Call-In: 1.1 mv (1 kc) Power Output: 14 watts per EIA Standard RS234 10 watts at less than 2% THD Load Impedance: 50 ohms (Balanced). Frequency Intercommunication: Shaped for Response: optimum articulation. DESCRIPTION The Altec 1556A ALTALK amplifier is a self con- tained unit incorporating a 14 watt power amplifier. The unit provides intercommunication facilities and program services for use in high power, high quality intercommunication installations. The am- plifier operates from 117 volts, 50-60 cycles power supply and the power consumption from the pri- mary source is 65 watts. The 1556A intercommunication unit is compact in design, requiring only 5 1/4” of rack space. It is designed for standard 19 rack mounting and is finished in Altec green. APPLICATIONS The 1556A ALTALK unit was designed with the intent to satisfy the requirement of transmitting and receiving conversations at a central point to and from other locations by use of remote speakers. The 1556A can be used to great advantage in warehouses, large automotive shops, manufacturing facilities, airports, and many other areas where intercommunication will increase the efficiency of operation. OPERATIONS AND USE OF CONTROLS In order to utilize the 1556A ALTALK to its greatest advantage, the function of each control should be completely understood. Therefore, it is essential that the instructions noted below are followed very carefully. The controls for the operation of the 1556A ALTALK amplifier are identified numerically in figure 1. Phono and Aux: +/- 1 db 20c. to 10 kc Microphone: 3 db at 50c. and 15 kc Controls: Intercom-Standby; Input Selector; Program-Talk-Listen; Normal- Return Speech; Listen Volume; Talk Volume; AC switch. Power Supply: 117 volts, 50-60 cps, 65 watts Tubes: 2 - 12AX7, 1 - 6DZ7, 1 - 6AX5 Dimensions: 51/4 H. 19 W. 61/2 D. Color: Dark Green Weight: 13 lbs. Accessories: Altec 1557A Speaker Selector Switch Panel; 1558A Program Selector Switch Panel; 13718 Call-in Switch Plate Assembly. FUNCTIONS The ON-OFF power switch,control 1,is located on the front panel of the 1556A ALTALK unit. Power for the ALTALK unit is obtained from any standard recep- tacle that supplies 105-125 volt, 50-60 cycles AC current. Separate volume controls for TALK and LISTEN, controls 2 and 3 are located on the front panel of the 1556A ALTALK unit (Figure 1). Each control is operated individually in order to achieve the desired level of listening and talking for all inter- communications (in and out). INTERCOMMUNICATIONS For Master to speaker area function set Intercom- Standby switch in Intercom position; select area to be called by setting proper selector switches on 1557A panel and press Program-Listen-Talk bar, control 4. Adjust outgoing sound level with Talk Volume, control 2. Release talk-listen bar to hear reply. Note: After completion of call return Intercom- Standby switch to Standby position. CALL-IN For the Master to receive call-in from any remote area the Intercom-Standby switch must be in the Standby position and the Program-Listen-Talk bar, control 4 in the Listen position. Simplicity of operation is achieved in answering the call-in by using the Normal-Return Speech bar, control 6. Simply press talk bar to answer and release to listen. RadioFans.CN 收音机爱 好者资料库 Note: When this control is used the switch on 13718 Call-in unit must be held in call position. PRIVACY CIRCUIT One of the outstanding features of the Altec 1556A ALTALK unit is the incorporation of a Privacy Cir- cuit. The use of the Privacy Circuit assures privacy (freedom from supervisory monitoring) in all remote areas. A more detailed description of this feature can be found on Instruction Sheet No. 13765, of 13718 Call-in Switch Plate Assembly. ALL CALL This facility is not furnished as part of the 1556A or 1557A units, however the I.C. - OFF - CHAN A and CHAN B switch positions on the 1557A are bussed and wired to the terminal panel for connection of relay or manual switching facilities. PROGRAM Set Intercom-Standby switch control 5, to Standby position; set Program-Listen-Talk bar, control 4 to Program. Any radio program material (AUX) or record player material (PHONO) will be heard thru the Speaker-Microphone on the Master. Establish the sound level by adjusting Listen Volume, con- trol 3. Auxiliary and Phono input sources are connected to pin jacks on the rear of the 1556A ALTALK unit, and selection of desired input source is accom- plished with Phono-Aux-Micro selector switch, con- trol 7. MICROPHONE A high impedance microphone may be connected to the phone jack at the rear of the 1556A Master. This microphone may be located remote from the Master for program pickup. When using micro- phone in this manner control 7 must be in the Micro position and the Program-Listen-Talk bar in the Program position. Note: When Phono-Aux-Micro inputs are in use the call-in feature is inoperative. After use, return control 4 to Listen position and control 5 to Standby position. PAGE 2 SINGLE AND DUAL CHANNEL PROGRAM DISTRIBUTION Program material may be distributed simultaneously with intercommunication facilities by adding sepa- rate program amplifiers (Altec amplifiers such as model 356A, 1568A, etc., are recommended). Block diagrams, figures 2 and 3 show typical single and dual channel systems. In these systems program material is amplified separately, permitting intercommunication service thru the 1556A ALTALK to continue without pro- gram interruption. WIRING Connect 2 conductor #22 AWG or larger twisted pair between terminals 3 and 4 on 1556A terminal strip to I.C. terminals on 1557A Speaker Selector Switch Panel. Connect loudspeakers and 13718 Call-In Switch Plate Assembly to 1557A Speaker Selector Switch Panel using 2 conductor #22 AWG or larger twisted pair to numbered terminals. (In many in- stallations shielded pair cable may not be required for this circuit.) Call-in and Privacy circuit must be 2 conductor shielded #22 AWG or larger twisted pair. Connect conductors to terminals 1 and 2 and shield to terminal 8 on 1556A terminal strip. Note: Installation may be simplified by loop- ing call-in circuit wiring from one speaker location to another. MAINTENANCE Since the Altec 1556A ALTALK Amplifier utilizes high quality parts, that operate within their speci- fied ratings, the need for routine maintenance is minimized. In the event that the 1556A ALTALK fails to operate properly, all external wiring should be checked immediately, as loose wiring or inadequate con- nections will result in noisy and intermittent opera- tion. Be extremely careful that no exposed wires come into contact with other wires, terminals, parts of the chassis or any other metal surfaces. RadioFans.CN 收音机爱 好者资料库 PARTS LIST 0.001 mfd 20% ,500 volt Disc. .01 mfd GMV, Goodall Epoxy Disc. 15-30-20 mfd, 400-300-250 Mallory PFP .047 mfd, 400 volt Micromold Tropicap 40 mfd, 450 volt, Mallory FP146 50 mfd, 25 volt TC 29 47,000 ohm 10%, 1/2 watt 3.3 megohm 10%, 1/2 watt 330,000 ohm 10%, 1/2 watt Potentiometer - Altec 12508 3,300 ohms 10%, 1/2 watt 1 meg ohms 10%, 1/2 watt 100,000 ohms 10%, 1/2 watt 270,000 ohms zb 10%, 1/2 watt 18,000 ohms 10%, 1/2 watt Potentiometer - Altec 13614 500 ohm, 5 watt Axial Lead 3,900 ohms 5%, 1 watt C1 C2,3,10,11,12 C4A, 4B, 4C C5, 6, 7 C8 C9 R1, 6, 8, 20 R2 R3, 4, 9 R5 R7 R10 R11, 12 R13, 14 R15 R16 R17 R18 R19 R21, 22 R23, 24, 25, 26 R27 S1 S2A, 2B, 2C S3 S4 S5 SR-1 T1 T2 T3 VI, 2 V3 V4 1,200 ohm 10%, 1/2 watt 47 ohm 10%, 1 watt 1,000 ohm 10%, 1/2 watt 62,000 ohm 5 %, 1/2 watt On-Off Switch - Altec 12536 Program - Listen - Talk Switch Altec 13612 Phono - Auxiliary - Micro Switch Altec 13610 Intercom - Standby Switch Altec 13609 Normal - Return Speech Switch Altec 13611 Rectifier - Selenium - Carl Holmes S-3W5PL-HD7 Input Transformer - Altec 4782 Output Transformer - Altec 16612 Power Transformer - Altec 6302 12AX7 Vacuum Tube 6DZ7 Vacuum Tube 6AX5 Vacuum Tube