Video Products
Technical Bulletin 30-2012-066
SUBJECT: DEGRADED AUDIO DISTORTION RATIO OR CROSSTALK WITH REAR XLR LINE AUDIO INPUT
DESCRIPTION
When rear XLR line input (1ch/2ch) is supplied, the audio distortion ratio may degrade or crosstalk may occur.
Distortion Ratio
Defective channel and symptom:
When 1ch is defective, the symptom occurs on 1ch.
When 2ch is defective, the symptom occurs on 2ch.
Crosstalk may be approximately 5–15 dB worse when measured with specific equipment (Rohde & Schwartz UPL) at low (20 Hz) and high (20 kHz) frequencies.
To correct the symptom, check and replace shorted diodes on the AXM board as described in the following modification procedure.
PARTS REQUIRED
| Part No. |
Description |
Qty. |
| 8-719-069-61 |
Diode, UDZSUSTE-1710B |
* |
* Quantity required depends on test result for each diode.
ORDERING INFORMATION
To order parts online, go to: www.sony.com/servicesplus. For service or parts ordering assistance, refer to the following document, which lists all contact telephone numbers:
Technical Bulletin 00-1999-000
MODIFICATION PROCEDURE
Equipment Required
Circuit tester
Headphones
Equipment to measure audio (Audio Precision SYS-2722 or equivalent)
Oscilloscope
AXM-41 or AXM-41A Board
(Side B, Zone A-2)
1. Using a circuit tester, check the conduction of diodes D1 through D8.
2. If any diode is shorted, replace the diode with a new one.
CONFIRMATION
1. Confirm that the new diodes do not short.
2. Confirm output of the channel on which the diode was replaced as follows:
a. Select the following settings:
Rear XLR line for audio input • AUDIO SELECT: MANUAL
Audio Level Volume: 0 dB (Input Level 5: set knob to mechanical center position)
b. Supply an audio signal of 1 kHz 22 dBu.
c. On headphones output, confirm that no audible symptoms occur.
d.On rear XLR 5-pin analog output, confirm that:
There is no noticeable distortion of the waveform on the oscilloscope.
The distortion ratio is less than 0.05%.
