SRK Electronics FMA501 Manual

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(ACN 089 050 564 ABN 44 089 050 564)

8 Victoria Grove

Hawthorn East

VIC 3123

Australia

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Summary of Contents for SRK Electronics FMA501

Page 1 (ACN 089 050 564 ABN 44 089 050 564) 8 Victoria Grove Hawthorn East VIC 3123 Australia...
Page 2 Setting power supply voltage Setting the date and time Protection Remote operation Maintenance Recommended maintenance schedule Circuit description Equipment overview Power supply Control board Amplifier palette Output directional coupler Trouble shooting Diagnostics Disassembly Drawings © 2007 SRK Electronics Pty Ltd...
Page 3 AN EARTH WIRE. IT IS IMPERATIVE THAT THIS EQUIPMENT IS CONNECTED TO A MAINS OUTLET THAT HAS AN EARTH. IN COUNTRIES WHERE EARTHED OUTLETS ARE NOT MANDATORY, IT IS THE CUSTOMER’S RESPONSIBILITY TO ENSURE THAT THIS EQUIPMENT IS APPROPRIATELY EARTHED. © 2007 SRK Electronics Pty Ltd...
Page 4: General Description
SRK Electronics FMA501 manual GENERAL DESCRIPTION The FMA501 is a high quality 500W amplifier intended for audio broadcast service in the FM band. Its features include: • Wideband • Energy efficient and high power factor • Extensive metering • Rugged design.
Page 5 This section details the way in which the FMA501 should be unpacked upon receipt by the customer. Note that if the FMA501 is installed in an SRK Electronics transmitter then this section is not applicable. The FMA501 should be removed from its packing, and the packing stored and used should it be necessary to return the FMA501 to the manufacturer.
Page 6: Installation
Departure from the instructions contained herein may void any warranty provided by SRK. The FMA501 has been designed to be mounted in a standard 19” rack frame, where it will occupy 3 rack units. Due to the weight of this unit, rear supports are also recommended.
Page 10: Operation
50Ω. Switching on and off The FMA501 is switched on by applying mains power. The LCD will light and show “Fwd Pwr”, meaning forward power, in watts. The FMA501 is now in operating mode. Assuming © 2007 SRK Electronics Pty Ltd...
Page 11 When done, press the knob again and the flashing will stop. The date and time have now been set. For security, the ability to select/deselect this function using the front panel can be disabled using the FD command via remote control. © 2007 SRK Electronics Pty Ltd...
Page 12 If the reflected power from the antenna exceeds 50W then the output RF power will be automatically reduced to bring the reflected power back to 50W. Under this condition the FMA501 will continue to function, albeit at a reduced output power, indefinitely until the reflected power reduces. The LCD will show “SWR HIGH”.
Page 13 Note that for temperatures of 99C and below, the leading zero is replaced with a space. ABI?<CR> Returns amplifier B DC current in the form XX.XA<LF><CR>>. For example: ABI?<CR> (command) (response from amplifier) _7.5A<LF><CR> > © 2007 SRK Electronics Pty Ltd...
Page 14 > Unlocked<LF><CR> (response from amplifier indicating that the front panel is unlocked) > ST?<CR> Returns the current standby/running status. For example: (command) ST?<CR> (response from amplifier indicating that it is in standby) Standby<LF><CR> > © 2007 SRK Electronics Pty Ltd...
Page 15 (response from amplifier indicating that command has been > executed) SD=XX/XX/XX<CR> Sets the date according to XX/XX/XX. For example: (command) SD=23/07/06<CR> (response from amplifier indicating that command has been Ok<LF><CR> executed) > ST=XX:XX:XX<CR> Sets the time according to XX:XX:XX. For example: © 2007 SRK Electronics Pty Ltd...
Page 16 Any data received by the amplifier, other than the commands listed above will generate the following error string: Invalid_command.__Send_HP?(CR)_for_command_syntax.<LF><CR> > Any data outside the valid range for the parameter concerned will generate the following error string: Incorrect_value_or_syntax.__Send HP?(CR)_for_help.<LF><CR> > © 2007 SRK Electronics Pty Ltd...
Page 17 SRK Electronics FMA501 manual Should it be necessary to make connection to the remote port using cables running external to the building housing the FMA501, it is recommended that external filtering and transient protection be installed on these lines. © 2007 SRK Electronics Pty Ltd...
Page 18: Maintenance
The air filter on the front panel should be regularly inspected and cleaned gently with warm water if necessary. If the operation of the date and time becomes erratic then replace the button cell on the control board. © 2007 SRK Electronics Pty Ltd...
Page 20: Circuit Description
Amplifier palette Output directional coupler • These assemblies are interconnected as per “FMA501 wiring diagram”. Please refer to fig 6.1 for the physical location of each sub-assembly. The power supply provides a nominal 50V DC for the RF transistors. The control board contains all metering and protection functions.
Page 21 RF enters the palette on J1 and passes through directional coupler U1. This provides a small sample of the input power across R17 and R18. This is rectified by D1 which thus provides a © 2007 SRK Electronics Pty Ltd...
Page 22 These voltages are passed to the control board to allow forward and reflected power to be measured and to ensure the correct operation of the protection functions. The directional coupler is manufactured using stripline techniques and should not be disassembled. © 2007 SRK Electronics Pty Ltd...
Page 23: Troubleshooting
20% of each other. If not, suspect the transistor with the lower current. Disassembly Commence by removing the IEC plug and all other external connections to the FMA501. This is to ensure the safety of those undertaking the disassembly. Remove the screws holding the upper lid and remove lid.
Page 24 Remove the PSU from the side panel by removing the four screws holding it in place. The PSU should now be free. All the sub-assemblies should now be free of the chassis. Further disassembly should be self evident. © 2007 SRK Electronics Pty Ltd...
Page 25 N TYPE N TYPE GN GREEN BL BLUE V VIOLET GY GREY N TYPE W WHITE RF IN P PINK AMPLIFIER PALETTE BK/R BLACK/RED GN/Y GREEN/YELLOW Title FMA501 WIRING DIAGRAM Size Number Revision Date: 1-Feb-2011 Sheet of File: C:\Client98\Files\FMA501overall.sch Drawn By:...
Page 26 TEST DSS9 LMC6462 CAP+ 220R 2N5401 10uF R4A 10K CAP- VOUT DSS9 10uF VR12 33nF 4N23 33nF AMP B CURR 33nF 220R ENCODER Title FMA501 CONTROL BOARD BIAS CUT Size Number Revision Date: 1-Feb-2011 Sheet of File: C:\Client98\Files\fma501cont4.sch Drawn By:...
Page 27 141 HARDLINE RF IN 86 HARDLINE RG316 100R 45nH 470pF ATC100B 10R/1W 470pF 470pF 5082-2800 MRF151G RG316 4.7nF 100K RFP-10-100 RFP-10-100 I/P POWER Title FMA501 AMPLIFIER PALETTE Size Number Revision Date: 1-Feb-2011 Sheet of File: C:\Client98\..\FMA501 amp palette.sch Drawn By:...
Page 29: Material Safety Data Sheet
MATERIAL SAFETY DATA SHEET PRODUCT IDENTIFICATION Trade Name: Beryllia Ceramic Chemical Family: Beryllium Compound Synonym: Beryllium Oxide, Beryllia, Thermalox, Super Beryllia HAZARDOUS INGREDIENTS Constituents OSHA(1995)* ACGIH(1994-95)* CAS # NIOSH/ RTECS # Beryllium PEL: 0.002 TLV: 0.002 7440-41-7 (Be) DS1750000 Ceiling: 0.005 TLV-STEL: NA 1304-56-8 (BeO) DS4025000...
Page 30 HEALTH HAZARD INFORMATION Emergency Overview: If this material is involved in a fire, pressure-demand self-contained breathing apparatus and protective clothing must be worn by persons potentially exposed to the metal fumes or airborne particulate. Primary Routes of Exposure: Inhalation: An exposure to airborne beryllium in excess of the occupational standard can occur when sintering, machining, grinding, sanding, abrasive cutting, polishing, laser scribing and trimming, chemical etching, crushing, or otherwise abrading the surface of this material in a manner which generates finely divided particles.
Page 31: Reactivity Data
INGESTION: Swallowing beryllium oxide dust can be treated by having the affected person drink large quantities of water and attempting to induce vomiting, if conscious. Obtain medical help. SKIN: Skin cuts and abrasions should be treated by standard first aid. Skin contamination can be removed by washing with soap and water.
Page 32 Respiratory Protection: When potential exposures are above the occupational limits shown in this MSDS, approved respirators must be used as specified by an Industrial Hygienist of other qualified professional. Respirator users must be medically evaluated to determine if they are physically capable of wearing a respirator. Quantitative an/or qualitative fit testing and respirator training must be satisfactorily completed by all personnel prior to respirator use.
Page 33: Special Precautions
VIII SPECIAL PROTECTION INFORMATION Transport Information: There are nor U.S. Department of Transportation hazardous material regulations which apply to the packaging and labeling of this product as shipped by ESPI. Hazard Communication regulations of the U.S. Occupational Safety and Health Administration require that this material be labeled. Regulatory Information: OSHA Hazard Communications Standard, 29 CFR 1910.1200: Beryllium is considered a hazardous ingredient.