User manual SOUNDCRAFT CPS650

[. . . ] Soundcraft shall not be liable for any loss or damage whatsoever arising from the use of information or any error contained in this manual, or through any mis-operation or fault in hardware contained in the product. No part of this manual may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, electrical, mechanical, optical, chemical, including photocopying and recording, for any purpose without the express written permission of Soundcraft. It is recommended that all maintenance and service on the product should be carried out by Soundcraft or its authorised agents. Soundcraft cannot accept any liability whatsoever for any loss or damage caused by service, maintenance or repair by unauthorised personnel. Harman International Industries Ltd. [. . . ] Forced convection, by means of a fan-tray, may be desirable in this situation. The CPS250/CPS275 will operate as a free-standing unit without requiring any special cooling arrangement, but should not be allowed to be accidentally or deliberately covered over in any way. Do not operate the unit with the top cover removed. The air intake and outflow holes must be inspected regularly and cleaned if necessary to maintain good airflow through the unit. This will be particularly important if the unit is used in a dusty environment. Finally, some consideration should be given to the earthing arrangement of the system at the centre of which are the console and the CPS250/CPS275 (and any other Soundcraft power supply units). The console chassis is earthed, through the mains earth, via the power supply. When rack-mounting the CPS250/CPS275(and any other Soundcraft power supply units) care should be taken to avoid any possible `ground loops' in the system which would introduce audible hum to otherwise clean audio signals. Ground loops may occur where signal processing equipment, patched to the console, has its signal earth commoned to the equipment chassis. The ground loop is 6 Installation formed if this chassis and the power supply chassis are in electrical contact through the fixing rails they share in the rack. To avoid this situation, standard isolating washers may be employed when fixing the power supply (or supplies) or any other unit into the rack. W A R N I N G : THIS APPARATUS MUST BE EARTHED. Under no circumstances should the mains earth be disconnected from the CPS250/CPS275 power supply unit. GENERAL As with all electrical/electronic equipment care should be taken when handling this unit. Avoid storage and operation in dusty locations and do not expose to corrosive atmospheres. To avoid risk of fire do not expose this unit to rain or moisture. Retain all packaging for transportation in the event of the unit requiring servicing. For touring/mobile transportation it is advisable to install the CPS250/CPS275 in a flight case to provide mechanical protection. Where the CPS250/CPS275 is enclosed in a touring case, provision must be made for adequate ventilation to the rear of the unit to ensure unrestricted supply of air for the cooling fan. Use only the high-current mains lead supplied, not the more common 5A type supplied with other equipment. Installation 7 PSU Linking (CPS275 Only) The output voltages from the CPS275 are fed via diodes as shown in the adjacent diagram. The TL783C maintains a fixed 1. 27 V between its ADJ and OUT pins, so the adjustable voltage-divider R22-PR3-R23 gives an output of approx 48V. Rail indicator LED2 is powered through DZ3, 4, which total 30V, so even a partial fall in rail voltage will extinguish it. D13 protects the regulator from reverse voltage if there is a charged capacitor across the output but the voltage on C31 has collapsed. D20 prevents the ADJ pin from rising above the OUT pin (due to the charge on C33) if the output is shorted. Diode D22 on the output (CPS275 only) allows supplies to be paralleled for redundancy. Technical Description 15 The +5V Supply. Max current rating 1. 0 Amps. This supply is primarily intended for powering console internal computers; it also powers the cooling fan. The AC input is fused by F4 and fullwave rectified by D9-12, with C36 as the reservoir capacitor. A protection diode is included; D14 protects the regulator from reverse voltage if there is a charged capacitor across the output but the voltage on C36 has collapsed. Diode D23 on the output (CPS275 only) allows supplies to be paralleled for redundancy. 16 Technical Description Servicing SAFETY. These safety notes are directed to those testing and repairing this power supply. Legal requirements mean that we must not encourage untrained personnel to take the lid off. Servicing should only be carried out by a competent service engineer. This supply contains mains voltages on the voltage select PCB, the mains switch, etc, and the usual precautions must be taken. The main reservoir capacitors have a capacity of 20, 000 uF, and are charged to +26V. [. . . ] The mutual shutdown can be disabled by linking pins 4 and 5 on BOTH opto-isolators IT IS ESSENTIAL THAT THIS IS REMOVED AFTER SERVICING IS COMPLETED!FAILURE TO DO THIS MAY CAUSE SEVERE CONSOLE DAMAGE IF ONLY ONE 17V RAIL SHUTS DOWN. If there is no power to the 723 IC (eg if R1 or R2 is open- circuit) the output will remain low, but no damage occurs. The regulator REG3 is the only part that is likely to fail. REPLACING COMPONENTS Replacement of any components should be undertaken only after switching the power supply unit OFF and disconnecting the mains supply lead from the power supply unit. Replacement of any of the fuses in the power supply units is possible without the removal of the circuit board. [. . . ]