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1.Overview
Thank you for purchasing BM54 repair kit.
Along with this guide it should help you retain sound on all channels on BM54 radios suffering poweramp failure which is
common to this type of module. Upon completion you'll have a fully functional BM54 with no recurring problem and
same or better sound than stock power amplifier. The poweramp IC used in this kit has better electrical characteristics,
and is better protected against short circuit, over temperature and overvoltage. It has better supply filtering and as the
stock model has an output pin for clipping detection (distortion).
2. Package contents
Your kit should contain the following:
-Amp PCB 4x40w audio amp with standby/clip detector control complete with components soldered
-connecting wires (output wires, input coax cables, supply
-Two screws with nuts/washers
-this guide
BM54 AMP Repair kit
Mura Car Accessories (MCA)
Str Doctor Iacob Felix, et 1, apt 1 011031,
Bucuresti, sector 1
T: (+4) 0756 76 79 64 | (+4) 0747 47 37 52
W: https://mca.electricmura.ro/ro
E: contact@mca.electricmura.ro
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Summary of Contents for MURA BM54
- Page 1 Thank you for purchasing BM54 repair kit. Along with this guide it should help you retain sound on all channels on BM54 radios suffering poweramp failure which is common to this type of module. Upon completion you’ll have a fully functional BM54 with no recurring problem and same or better sound than stock power amplifier.
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Page 2: Mounting /Installation Instructions
Mura Car Accessories (MCA) Str Doctor Iacob Felix, et 1, apt 1 011031, Bucuresti, sector 1 T: (+4) 0756 76 79 64 | (+4) 0747 47 37 52 W: https://mca.electricmura.ro/ro E: contact@mca.electricmura.ro 3. Mounting /installation instructions 3.1 Disassembly Open top cover... - Page 3 Mura Car Accessories (MCA) Str Doctor Iacob Felix, et 1, apt 1 011031, Bucuresti, sector 1 T: (+4) 0756 76 79 64 | (+4) 0747 47 37 52 W: https://mca.electricmura.ro/ro E: contact@mca.electricmura.ro Remove main BM54 PCB from housing.
- Page 4 Mura Car Accessories (MCA) Str Doctor Iacob Felix, et 1, apt 1 011031, Bucuresti, sector 1 T: (+4) 0756 76 79 64 | (+4) 0747 47 37 52 W: https://mca.electricmura.ro/ro E: contact@mca.electricmura.ro 3.2 Preliminary work with the board Cut traces as indicated below. This way you isolate old poweramps from the circuit.
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Page 5: Connection Points
Mura Car Accessories (MCA) Str Doctor Iacob Felix, et 1, apt 1 011031, Bucuresti, sector 1 T: (+4) 0756 76 79 64 | (+4) 0747 47 37 52 W: https://mca.electricmura.ro/ro E: contact@mca.electricmura.ro 3.3 Connection points BM54 Poweramp kit connection points. (indicated in red) - Page 6 Mura Car Accessories (MCA) Str Doctor Iacob Felix, et 1, apt 1 011031, Bucuresti, sector 1 T: (+4) 0756 76 79 64 | (+4) 0747 47 37 52 W: https://mca.electricmura.ro/ro E: contact@mca.electricmura.ro BM54 main PCB connection/soldering points Input connections, standby/mute signal:...
- Page 7 Bucuresti, sector 1 T: (+4) 0756 76 79 64 | (+4) 0747 47 37 52 W: https://mca.electricmura.ro/ro E: contact@mca.electricmura.ro Output (Speaker) connections: You can use two locations for connecting speaker outputs to BM54 board. 2. Also showing power supply soldering points.
- Page 8 Mura Car Accessories (MCA) Str Doctor Iacob Felix, et 1, apt 1 011031, Bucuresti, sector 1 T: (+4) 0756 76 79 64 | (+4) 0747 47 37 52 W: https://mca.electricmura.ro/ro E: contact@mca.electricmura.ro Clip detector soldering point.
- Page 9 Now connect each wire to corresponding Poweramp board socket. Don’t forget to check for correct polarity/signals wiring between the two PCBs. Next you have to drill 2 holes in BM54 chasis so you can mount poweramp board using the screws/nuts supplied. After that, mount main BM54 PCB into chasis and mount retaining clip (3) to slightly fix the board into place.
- Page 10 -Don’t let the washers touch ic terminals -use a non-conducting spacer between amp PCB and bm54 tuner metallic shield. -Be sure to use a spacer between poweramp board and BM54 metallic RF shield beneath. Neglecting that you might get shorts between terminals and metallic RF...
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Page 11: Signal Description
Mura Car Accessories (MCA) Str Doctor Iacob Felix, et 1, apt 1 011031, Bucuresti, sector 1 T: (+4) 0756 76 79 64 | (+4) 0747 47 37 52 W: https://mca.electricmura.ro/ro E: contact@mca.electricmura.ro 4. Signal description Supply: VCC=supply voltage for poweramp circuit... - Page 12 You’ll further damage your module if you’re doing that. Other mistake is to remove the old epoxied poweramps with back-plate which additionally to heat transfer it acts like a spacer between main PCB and BM54 chasis. If you remove the chips and don’t retain the spacers you’ll risk to shortcircuit your whole module rendering it unusable and possible unserviceable.
- Page 13 Mura Car Accessories (MCA) Str Doctor Iacob Felix, et 1, apt 1 011031, Bucuresti, sector 1 T: (+4) 0756 76 79 64 | (+4) 0747 47 37 52 W: https://mca.electricmura.ro/ro E: contact@mca.electricmura.ro...
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