LG / GOLDSTAR 512I
Service Manual

GOLDSTAR 512 I
Matrix
Item See Model Book
6 6 6 6 6 Safety Notes ................................................................................ Goldstar P934 I Mechanism Adjustments ........................................................... Goldstar P934 I Mechanism Disassembly ........................................................... Goldstar P934 I Mech Troubleshooting ............................................................... Goldstar P934 I Deck Exploded View .................................................................. Goldstar P934 I Electronic Test Equipment Oscilloscope Video Signal Generator Level Meter Frequency Counter + Driver Test Tape (SP) Recording Tape Digital Multimeter Monitor Scope Power Supply ABBREVIATIONS The Fixture uses in Deck Assy Checking. 1) Fixture Cable (I) (Fix. 1) Parts No: 6871R-0288B (Optional Parts) (1) Refer to �Disassembling�. (2) Assemble like figure 2-3 and connect with service extension fixtures 5EA. (3) Short two Tin wires W539 and W579 on Main C.B.A so that the end sensor (Supply sensor, Take up sensor) and supply Reel Sensor, Take up Reel Sensor are not operating. (4) Insert Video Cassette Tape (Then push CST switch for a moment during inserting the Tape). (5) Check and replace Mechanical parts. (6) After eject the Video Cassette Tape (Then push the CST switch like above No(4)). (6) In reassembling, you must open Tin Wires W539 and W579. Note: (1)In disassembling and reassembling, be careful not to be damaged CST switch. > The Green line of each FIX. must be connected with No.(1) Pin of each connector. SPEC: SPECIFICATION M.P: MEASUREMENT POINT A.P: Adjustment Point 1. Servo Circuit 1) PG Adjustment WAVEFORM Composite Video Signal

1
Electrical Adjustments
MODE: Playback SPEC: 6.5H ±0.5H (41 6usec, 1H=64usec) M.P : W393/W394(H.SW) JK401 (Video Out) A.P :VR201 Purpose: For the phase dividing of the Video A,B heads with 1800 and the exact trackign of each track to meet head switching point with VHS Spec. Procedure: a. Playback a PAL SP test tape. b. At this time, the �ART� is lighting, after pressing the A.TR(+) or A.TR(-) and adjust the X-Value. c. Connect CH-1 terminal of oscilloscope to W393/W394(H.SW) and CH-2 terminal to Video Out terminal (JK401) of VCR. d. Trigger the complex Video signal of CH2 to CH-1 (H.SW) and adjust VR201 so that the distance from A(B) head selection point of H.SW signal to the starting point of Vertical synchronized signal is 6.5H (416u sec, 1H=65usec). e. The conversion of A/B Head SW signal uses the Polarity Invert Knob of oscilloscope. Reference: 1. ± PG adjustment is practiced in the state of maximum RF level and locked servo system (Manual tracking Mode). 2. The deviation between A/B Head Adjustment location should be within ±0.5H (34t sec). 3. The deviation between the specification of adjustment and the practical measurement value should be within ±0.5H (32u sec). 4. Oscilloscope and VCR set should be connected with GND. 2. Audio Circuit 1) Record Bias Adjustment MODE: Record SPEC: 2.8mv ±0.1mv RMS M.P: W454 (±) (REC Bias +) W446 (-) (REC Rias -) A.P :VR401 Purpose: This is adjusting the bias current to specification in recording. Procedure: a. Connect (+) terminal of the Level Meter to W454 (+). b. Connect (-) terminal of the Level Meter to W446 (-). c. Confirm that the Oscillation Voltage is 2.8mV -F 0.1mV RMS. d. At this time, adjust VR401 and make the oscillation voltage fit to specification. 3. Tuner/IF circuit 1) VCO (Voltage Controlled Oscillation) Adjustment MODE: PAL BIG (38.9MHz) SPEC :DC 2.5 ± 0.1V M.P : PM701 pin (6) A.P :T750 (Automatic Frequency Control) (VCO COIL) Procedure: a. Connect as shown in Fig. 3-2 (next page). b. Input the PAL B/G 38.9MHz (Strength of input electric field: 75±5dBu) signal OUT Terminal of TV RF Pattern GEN instrument. c. Confirm that the video signal is Output by

U-View Limited
connect oscillsocope to PM701 PIN(9). d. Adjust VCO coil T750 so that the voltage of PM701 pin(4) became DC 2.5±0.1V. 2) RF AGC (Automatic Gain Control) Adjustment MODE E11 CH (217.25MHz) SPEC: 5370.1Vp-p M.P: W705/W719 (AGC TP) A.P: VR701 Procedure: a. Be tuning PAL B/G E11CH (strength of input electric field: 70±dBu). b. Connect the Digital Voltmeter to Tuner W705/ W719 (AGC TP). c. Adjust VR701 so that the digital voltmeter is 5.3± 0.1V p-p. Reference: Maintain the input gain in adjusting AGC faithfully.

Service Cables
1. Electrical Service Fixture List

2) To Check and replace Mechanical parts Disassembly Flow (1)Top Case > (2)Bottom Cover > (3)Front Panel > (4) Housing & DeckAssy (6)Main C.B.A

2) Fixture Cable (2) (Fix. 2) Parts No: 6871 R-0288A (Optional Parts)

Fig. 3-1

3) Fixture Cable (3) (Fix. 3) Parts No: 6871 R-0288M (Optional Parts)

Cabinet Exploded Parts View
Fig. 2-3

4) Fixture Cable (4) (Fix.4) Parts No: 6871 R-0288E (Optional Parts)

Cabinet Parts List
Location A43 A46 250 252 255 256 257 260 265 268 275 280 283 284 300 320 323 330 452 462 469 Description 258-800S PANEL 3501R-0554G 217-665D CASE 257-100A PLATE 4930R-0008A 3300R-0030A 3301R-0004A 3210R-0004A 324-995A 3300R-0011A 4930R-0003A 258-801P 3580R-0009U 442-681A SPRING 681-142G 3721R-D002B 3111R-0005A 3550R-0013A 353-051A 353-136A 353-046K Specification ASSY FRONT BOARD ASSY MAIN

5) Fixture Gable (5) (Fix.5) Parts No: 322-065B (Optional Parts)

TOP GND(M/F FIX) HOLDER TUNER PLATE DRUM SHIELD PLATE ASSY BACK SHIELD FRAME MAIN HOLDER PWB PLATE SIDE GND(FTZ) HOLDER DIGITRON PANEL FRONT DOOR CST DOOR CORD H03VVH2-F 2-0.75MM(2X0.5MH)CN PANEL ASSY DISTRIBUTOR (SCART) CASE ASSY PRE-AMP COVER BOTTOM SCREW SPECIAL (3X10 FZMY) SCREW SPECIAL (4.6X12.5 FBK) SCREW SPECIAL (3X10 B.K)