ARP Quadra

• On the rear of the unit all but the mains switch have been replaced. This includes all new Switchcraft 1/4 inch and 1/8 inch Jack sockets, Switchcraft XLR male socket , new IEC Mains Inlet socket and new program protect toggle switch.


• The keyboard has had all its bushes replace and the buss bars and j wire contacts have been straightened and cleaned. The key caps have been cleaned and levelled.


• The Aftertouch sensor has been replaced with a new ‘Force Sensing Resistor’.


• All of the sliders on the Quadra have been removed, disassembled, cleaned, deoxit-ed, lubricated, reassembled, tested and reinstalled.


• Three broken sliders have been replaced.


• The power supply unit has been completely over hauled. The includes all new main smoothing caps, decoupling caps, replacing tantalum capacitors for wet electrolytic capacitors and replacing ceramic capacitors too.


• The power transistors are new as are the plus 5 volt regulators. The linear power supply regulator is new. I've replaced all the rectifier diodes and power resistors. I've replaced the PSU trimmer for a new CTS trimmer.


• I've also added two new 20mm fuse holders, to facilitate use of replacement, the original fuses were 32mm wire ended and soldered in.


• All tantalum decoupling capacitors have been removed from the Quadra. Where tantalum capacitors we're used to decouple the power supply lines, I've replaced them with wet electrolytic capacitors. Where the a tantalum capacitor functioned as a timing element I replace them with new tantalum capacitors.


• All Molex headers,sockets and plugs have been replaced with new Molex products. This includes connectors on the keyboard. Also all wire-to-Molex crimps have been removed and re-crimped with new Molex crimps.


• Where necessary any ribbon cable that has been damaged has been replaced with original NOS ARP ribbon cables.


• All the sustain capacitors on the upper and lower poly boards have been replaced.


• The two ARP filter modules ( 4075) have been recapped and had the extended range mod installed to extend the cut off frequency to 20KHz.


• Most of the logic ICs on the keyboard interface board have been replaced.


• The CPU board needed various new logic chips , along with new memory and a new Microcontroller. The DAC is new.


• Various LEDS have been replaced with original NOS ARP stock.


• Finally the end panels have been replaced with new leather end cheeks.


• Unit is calibrated and fully working.

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