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SERVICE MANUAL
MDR-RF940R is headphones
in MDR-RF940RK.
Notes on chip component replacement
• Never reuse a disconnected chip component.
• Notice that the minus side of a tantalum capacitor may be dam-
aged by heat.
Flexible Circuit Board Repairing
• Keep the temperature of the soldering iron around 270 ˚C during
repairing.
• Do not touch the soldering iron on the same conductor of the
circuit board (within 3 times).
• Be careful not to apply force on the conductor when soldering or
unsoldering
MICROFILM
MDR-RF940R
SPECIFICATIONS
AEP Model
HEADPHONES
Related Manuals for Sony MDR-RF940R
Summary of Contents for Sony MDR-RF940R
- Page 1 MDR-RF940R SERVICE MANUAL AEP Model MDR-RF940R is headphones in MDR-RF940RK. SPECIFICATIONS Notes on chip component replacement • Never reuse a disconnected chip component. • Notice that the minus side of a tantalum capacitor may be dam- aged by heat. Flexible Circuit Board Repairing •...
- Page 2 SECTION 1 This section is extracted from instruction manual. GENERAL – 2 –...
- Page 3 MDR-RF940R SECTION 2 DISASSEMBLY • This set can be disassembled in the order shown below. HANGER (R), RX BOARD HOUSING (R) HANGER (R), RX BOARD 3 hanger (R) (Page 3) (Page 4) 6 two head bands 4 RX board HOUSING (L), SW BOARD...
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Page 6: Section 4 Exploded Views
MDR-RF940R SECTION 4 EXPLODED VIEWS NOTE: • Items marked “*” are not stocked since they • -XX and -X mean standardized parts, so they may have some difference from the original one. are seldom required for routine service. Some • Color Indication of Appearance Parts delay should be anticipated when ordering these items. - Page 7 (2) HEADPHONE (L) SECTION Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark 4-966-801-11 COVER (SWITCH) 4-987-590-01 TERMINAL (+), BATTERY 4-966-811-01 PAD, EAR 4-987-592-01 TERMINAL (COMMONNESS), BATTERY 4-966-786-01 SCREEN (FRONT) 4-966-799-11 CAP (L) 4-966-785-01 REGISTER, FRONT 4-966-793-11 HOUSING (L) 4-966-808-01 LID, BATTERY CASE 4-966-796-11 PLATE (L), FRONT A-4540-414-A SUSPENDER ASSY...
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Page 8: Section 5 Electrical Parts List
SECTION 5 ELECTRICAL PARTS LIST NOTE: • Due to standardization, replacements in the • Items marked “*” are not stocked since they When indicating parts by reference number, please include the board. parts list may be different from the parts speci- are seldom required for routine service. - Page 9 Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark 1-107-725-11 CERAMIC CHIP 0.1uF 8-729-200-63 TRANSISTOR 2SC2712L-TE85R 1-126-246-11 ELECT CHIP 220uF 8-729-200-63 TRANSISTOR 2SC2712L-TE85R 1-126-246-11 ELECT CHIP 220uF 8-729-027-36 TRANSISTOR DTA143XKA-T146 1-107-826-11 CERAMIC CHIP 0.1uF 8-729-040-78 TRANSISTOR DTA124GKA-T146 1-104-847-11 TANTALUM CHIP 22uF 8-729-020-92 TRANSISTOR XN1504-TX <...
- Page 10 MDR-RF940R Ref. No. Part No. Description Remark 1-216-051-00 METAL CHIP 1.2K 1/10W 1-216-067-00 METAL CHIP 5.6K 1/10W 1-216-061-00 METAL CHIP 3.3K 1/10W 1-216-067-00 METAL CHIP 5.6K 1/10W 1-216-061-00 METAL CHIP 3.3K 1/10W 1-216-061-00 METAL CHIP 3.3K 1/10W 1-216-097-00 METAL CHIP...
- Page 11 MDR-RF940R AEP Model SERVICE MANUAL Ver. 1.0 1998. 05 SUPPLEMENT-1 File this supplement with the service manual. Subject: 1. Modification 2. Electrical Adjustments...
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Page 12: Schematic Diagram
1. MODIFICATION • Countermeasure for distortion and white noise. Improvement of MDR-RF940R Increase the value of C65 of RX board. Add a 22 pF capacitor in parallel with C65. Please use the following part. Chip ceramic capacitor 22 pF 1-163-235-11 or 1-163-235-91 SCHEMATIC DIAGRAM •... - Page 13 2. ELECTRICAL ADJUSTMENTS Note: • Perform countermeasure for distortion before adjustments. Adjust and confirm the unit by following procedure shown below after this countermeasure. • Please adjust the transmitter and the headphone together. Procedure for Measurements and Adjustments Lastly, we would like to explain the procedure for adjusting this model. As this model adopts a Stereo Modulation method called “FM- FM”, it is difficult to perform the adjustments with common measurement equipments.
- Page 14 AF signal or music Procedure: 1) Input any signal including music into TMR-RF940R and place the unit the point where is far from MDR-RF940R and place the unit in a location where is far from by 5 m. 2) Measure the DC voltage at the test point TP2 of RX board of MDR-RF940R.