Galvin-Mfg-Co（Motorola）-AT-58-Tuner 电路原理图.pdf

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1、MANUAL OF 1951 MOST-OFTEN-NEEDED RADIO DIAGRAMS AUTOMATIC TUNER AT-S8 GENERAL INFORMATION DESCRIPTION top deck, unhook springs (53) and links (25). Grasp top deck and lift up and tip back. This leaves both decks open for servicing. See Tlgures 1 and 2. Automatic Tuner AT-58 Is used In Motorola spe c

2、lflc auto receivers. This Is a 3-gang permeability type tuner, mech anically operated by movement .of Its push buttons. Five pre-set and one manual tuning positions are provided. The frequency range Is 535 to 1600 Kc. The pre-set positions can be set In any sequence to any frequency within this rang

3、e. SERVICING LOWER DECK Looking at the top of the lower deck (with front to you), on the right we have the manual drive lead screw assembly (42). The other 5 assemblies (43) are the station set-up screw assemblies. Note that all assemblies can be easily lifted out after springs (50) are unhooked. SE

4、RVICE TOOLS The simplicity of the tuner allows easy servicing with: Note also that unless a push button arm (1) Is pushed In, all assemblies lay flat. When a push button arm (1) is pushed In, the assembly is tilted about 30. 1. 1/4* open end and 1/4* box end wrench. 2. A stiff steel hook 1/16* diame

5、ter made of 1/8* rod, ground down and shaped like a #5 to #10 size crochet hook, to hook and unhook the springs. Visual Inspection will show correct location of all springs In the assemblies and those which hold down the assemblies. 8. Slab head wrench for coll adjustment: #2/56 head. TO REMOVE TOP

6、DECK Unscrew two #8 sheet metal screws (45) on the back of the tuner and two #8 sheet metal screws (45) on the top front of the tuner. (Do not unscrew screws (45) at trimmer bracket). Before removing (Service material on Tuner AT-58 is continued on the next three pages.) 收音机爱 好者资料库 RadioFans.CN MANU

7、AL OF 1951 MOST-OFTEN-NEEDED RADIO DIAGRAMS Motorola Automatic Tuner AT-58, continued from previous page. Note action of gear train as manual knob is turned and push button arm Is pushed In so gears mesh. Automatic tuning buttons can be checked for any binding by trying each button. DRIVE ARM ADJUST

8、MENT It Is very Important that the carriage drive assembly (12) be correctly adjusted In Its bearings so as not to bind or be too loose and allow it to twist and force the tuner out of alignment. On the left side of the lower deck, you will find a set screw (47) and lock, nut (30) for assembly adjus

9、tment. Note that the assembly is floated In the base bracket (7) between two ball bearings (4), one on each end. Adjust by loosening locknut (30) and then turn set screw (47) so that all bearing play Is eliminated but yet carriage drive assembly (12) moves freely. Tighten locknut (30) after ad justm

10、ent. Before hooking spring (54), tip the tuner several times to make sure carriage drive assembly (12) Is free enough to swing up or down by Its own weight. POINTER REPLACEMENT The pointer Is easily removed by downward and outward pressure to unhook It from the pointer arm (2). Pointer Is replaced b

11、y reversing procedure. ANT., RF OR OSC. CORE REPLACEMENT The tuner cores (18) are easily unscrewed from clip (14) and pulled out when carriage assembly (13) Is extended. Note that the cores are coded with a paint dot on the screw portion; always use replace ment cores bearing the same color coding.

12、When or dering replacement cores, always specify color coding together with part number. TO SET THE PUSH BUTTONS 1. Turn receiver on and allow it to warm up for a few minutes. 2. Push the first automatic tuning button In as far as It will go and HOLD IT that WAY. 3. With the tuning knob, tune In the

13、 station you desire to set up. Tune carefully until you are ex actly on the station; tuning to either side of it will result in poor tone quality. The pointer will Indicate station being set up. Release button and knob after tuning in station. A. Follow above steps 2 and 3 for the remaining four but

14、tons. SERVICE INFORMATION The entire top deck of this tuner may be re moved, while tuner is mounted In receiver chassis, allowing complete accessibility to all mechanical parts. TO REPLACE PARTS ON LOWER DECK Remove top deck of tuner (follow previous In structions). This exposes the 5-statlon set up

15、 screw assemblies (43) and manual lead screw assem bly (42). These may be removed by unhooking spring (50) and lifting them out. If push button arme or slider arms are to be replaced. It will be necessary to remove spring (54); then take out screws (48) from bottom of tuner to allow bracket (7) to m

16、ove back and permit push button arm assemblies (1) or slider arms (3) to be removed after springe (53) have been removed. SERVICE 1. STATION DRIFT (Push Buttons). Check the flat friction spring (58) for breaks or permanent set. 2. TUNER STICKING. Check collars on manual drive assembly (42). If they

17、are cocked or stuck, re place with new assembly. 3. HARD TUNING FOR PRE-SETTING. Check lubricant on the gear train. It should be Stayput #512 or equal. 4. TWISTING CARRIAGE PLATE. Due to poor setting of carriage drive assembly (12). See Drive Arm Adjustment. 70 Patience Is required, to assemble push

18、 button, arm assemblies (1) and slider arms (3) back into bracket (7). Reassemble tuner by working In re verse order. Test all parts of lower deck for free opera tion before assembling to upper deck. TO REPLACE TOP DECK Make sure that carriage drive assembly (12) is tipped back (spring (54) unhooked

19、) am carriage assembly (13) carrying the tuning cores Is out. Slip in the top deck, making sure the spring washer (70) on the manual drive assembly (42) is between the drive assembly gear am the back of the base before putting in screws and locking the two decks together. HINTS 6. ROUCH DRTVE - Check die cast gears (13,20 Figure 2, showing location of additional parts is on the next page, over) li 52 52 li. u _ L J - * 收音机爱 好者资料库 RadioFans.CN