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TheSoundSteward · 29th December 2005

I am troubleshooting an Marshall AR-300 Tape eliminator. This unit sports 2 encoder/decoder pc boards manufactured by dbx in 1982. The cards are 2.6" x 4.0" and use a 12 pin molex connector numbered 7 thru 18 on one long edge to make connections. There are 4 pots along the other long side of the board labeled "VCA sym", "Rec Level", "Play Level", "RMS Sym". There are 2 LM301A's, a 4558, a CA3046, a CA3083, a pair of transistors wrapped in tin-foil, and 3 fat tantalum capacitors, one of which on my 2 boards caught fire and looks like a toasted marshmallow. There is no obvious part number for the circuit board. The rear (solder) side has the dbx logo and the numbers 260174 06 near pin 18 (ground) of the connector and the letters CD-B1 near pin 7.

This same board was also used in the Eventide 910 Harmonizer, and probably several other OEM devices that needed compression and expansion of dynamic range prior to processing.

Can anyone out there

1. Help me identify a part number for this pcb?
2. Have a pinout of the board?
3. Have the schematic of the board?
4. Have the adjustment procedure for the board?

Thanks,

29th December 2005	#1
TheSoundSteward Gear Head Joined: Dec 2004 Location: Fullerton, California Posts: 32 Thread Starter	dbx encode/decode pcb schematic needed I am troubleshooting an Marshall AR-300 Tape eliminator. This unit sports 2 encoder/decoder pc boards manufactured by dbx in 1982. The cards are 2.6" x 4.0" and use a 12 pin molex connector numbered 7 thru 18 on one long edge to make connections. There are 4 pots along the other long side of the board labeled "VCA sym", "Rec Level", "Play Level", "RMS Sym". There are 2 LM301A's, a 4558, a CA3046, a CA3083, a pair of transistors wrapped in tin-foil, and 3 fat tantalum capacitors, one of which on my 2 boards caught fire and looks like a toasted marshmallow. There is no obvious part number for the circuit board. The rear (solder) side has the dbx logo and the numbers 260174 06 near pin 18 (ground) of the connector and the letters CD-B1 near pin 7. This same board was also used in the Eventide 910 Harmonizer, and probably several other OEM devices that needed compression and expansion of dynamic range prior to processing. Can anyone out there 1. Help me identify a part number for this pcb? 2. Have a pinout of the board? 3. Have the schematic of the board? 4. Have the adjustment procedure for the board? Thanks, __________________ Steve Hogan