Beosound 3000 Type 2671-2680 .pdf - abo - center
Beosound 3000 Type 2671-2680 .pdf - abo - center
Beosound 3000 Type 2671-2680 .pdf - abo - center
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5.14 Repair tips, English<br />
Test of Master Link DATA receiver/transmitter<br />
Test of the circuits 12TR30, 12TR31, 12TR52, 12TR53, 12TR55, 12TR56 and 12IC6.<br />
- Lift P107.<br />
- Mount on P4.<br />
- Connect a square-wave generator 10kHz 0-5 V to P107-4 (transmit).<br />
- Measure P107-2 (receive) with an oscilloscope; it should produce the same signal<br />
as the one transmitted by P107-4, only here it is delayed by 10-15 µS.<br />
ABO-CENTER v/HENRIKSENS ELEKTRONIK<br />
To prevent that products connected via the Master Link socket destroy the data<br />
communication in the case of an error in the data interface, the data interface<br />
circuit has been designed so that components can be defective without causing a<br />
malfunction.<br />
For example, the diodes mounted in connection with Data- and Data+ are protection<br />
diodes which will protect against static electricity.<br />
Consequently, when making a repair, it may be necessary to replace/check several<br />
components.<br />
If 12TR55 is defective, both 12TR55 and 12TR56 should be replaced and the<br />
diodes 12D4, 12D5, 12D19, 12D20, 12D21 and 12D22 should be checked.<br />
If 12TR56 is defective, both 12TR55 and 12TR56 should be replaced and the<br />
diodes 12D4, 12D5, 12D19, 12D20, 12D21 and 12D22 should be checked.<br />
If one of the diodes 12D4, 12D5, 12D19, 12D20, 12D21 and 12D22 is defective,<br />
all of the diodes should be replaced, and 12TR55 and 12TR56 should be checked.<br />
CD laser current<br />
Across 80R3121 (4.7 ohm) the measurement in mV will show the current in the<br />
laser beam. Typical measure; ap. 300 mV. If over 450 mV the laser-head is defect.<br />
Eyepattern<br />
The eyepattern can be measured between 80P1001 pin 5 and 80C2116 (1.3Vpp).<br />
Exchange of microprocessor module PCB3<br />
When exchanging PCB3 remember to insert the EEPROM from the defective<br />
module, because it contains valuable data (serial no., type no., PIN-code etc.).<br />
The data is not transferred to the new module untill you have been in contact with<br />
the theft protection or after 12 hours connected with mains. This means that you<br />
can try out a new PCB3 without transferring the products serial no. Etc..<br />
Note !<br />
When the serial no. has been transferred to the micro-processor it can only be<br />
used for this specific product; it must go back to Bang & Olufsen’s module repair<br />
department as an exchange module to be erased again.<br />
If the product functions are OK the theft protection is also OK; there is no need for<br />
testing the functionality of the theft protection.<br />
When the product is connected to mains, wait 20-30 sec. before operating.<br />
All addresses in ML has to be updated after disconnecting mains voltage.