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RP-SM304A Go back

The Parastream RP-SM304A is a replacement part for the Siemens SM304A integrated circuit used in the Korg BX-3 and CX-3 combo organs, circa 1980. The Siemens SM304A is a keyboard encoder that converts 32 parallel keyboard inputs into a serial stream. These original Siemens parts were very difficult to find.

The RP-SM304A is a small printed circuit board that plugs directly into the 40-pin socket of the BX-3/CX-3 KLM-244 board. It utilizes surface-mount CMOS technology to realize its small size and low power consumption.

The Korg CX-3 uses two SM304A parts on one KLM-244 board. The BX-3 uses four SM304A parts on two KLM-244 boards. An adapter socket (23-00040615) is included with each RP-SM304A to facilitate mounting of the RP-SM304A in some circuit boards.

You may view or download the RP-SM304A datasheet and the RP-SM304A installation instructions. There is also a FAQ page for Frequently Asked Questions.

Key Benefits

  1. Functional replacement for the original Siemens SM304A part in most applications.
  2. Plugs directly into the IC socket on the PC board.
  3. SM304As may be replaced one at a time — Some other solutions require both to be replaced at the same time.

RoHS Compliance

The Parastream RP-SM304A is categorized as “Spare parts for equipment in service,” and is exempt from the RoHS (Lead-free) directive. The Parastream RP-SM304A is manufactured using non-RoHS compliant components and solder.

Pricing and Ordering

These parts are out of stock and we do not have plans to replace our inventory in the near future. Please order the original Siemens SM304A IC as an alternative.

DescriptionPart NumberAvailabilityUnit Price (USD)QuantityOrdering
IC, Siemens SM304A Keyboard Encoder, PDIP-40 (New Old Stock)39-000030417 in stock, more in 30 days$90.00
IC, Siemens SM304A Keyboard Encoder, PDIP-40 (Pulled)39-001030413 in stock$65.00

Important information for Customers outside the US: If you choose to ship via International Economy, Parastream can only guarantee that your shipment arrives at the point of entry into your country. The tracking number may not provide status once it reaches your country. Parastream will not be able to offer any assistance in tracking your shipment once it reaches your country. If you require complete end-to-end tracking and delivery guarantees, you should choose Standard International. More information...


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