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DATAMATH CALCULATOR MUSEUM

Radio Shack EC-430 (65-570A)

Date of introduction:	October 1987	Display technology:	LCD
New price:	$14.95 (SRP October 1987)	Display size:	8
Size:	2.7" x 6.0" x 0.25" 68 x 153 x 8 mm³
Weight:	2.4 ounces, 68 grams	Serial No:
Batteries:	LR54	Date of manufacture:	mth 08 year 1992
AC-Adapter:		Origin of manufacture:	Thailand
Precision:	8	Integrated circuits:	Toshiba T7752S
Memories:	3
Program steps:		Courtesy of:	Joerg Woerner
		Download manual:	(US: 2.1 MByte)

Radio Shack, acquired by Tandy Corporation in 1963, entered the market of Checkbook Calculators in November with this EC-306. It features Account Manager functionality with three permanent (till you remove the batteries) Memories and started a very successful product line. We discovered as of now seven (w/o counting Tandy versions) different family members:

• 1982: Radio Shack EC-306 / 65-696, 3 Memories
• 1982: Tandy EC-306 / 65-696, 3 Memories
• 1987: Radio Shack EC-308 / 65-996, 3 Memories
• 1987: Radio Shack EC-430 / 65-570, 3 Memories, Taiwan
• 1988: Radio Shack EC-430 / 65-570A, 3 Memories, Thailand
• 1996: Radio Shack EC-455 / 65-569, 1 Memory, TAX
• 2000: Radio Shack 65-504, 3 Memories, TAX, violet CC keys
• 2002: Radio Shack 65-504A, 3 Memories, TAX, blue CC keys

Dismantling the featured Radio Shack statesman EC-430 calculator manufactured in August 1992 in Thailand reveals a clean design centered around a Toshiba T7752S single-chip calculator circuit soldered on a double-sided printed circuit board (PCB) and powered by by four solar cells and a small LR54 (LR1130) backup battery. Learn how to decipher the 8A2 date code on the pictured calculator.

Inspecting the PCB of this EC-430 manufactured in 1992 brought our attention to a small mark reading 308-18, most likely a reference to Type 308, and Revision 18 of the design (schematics and layout). We noticed the PCB-Mark 308 during our research on the PCBs of a lot of more or less identical Account Managers, find an overview of the OEM brands/models here.

Please find an overview of the PCB-Marks we discovered so far on Account Manager calculators.

Learn more about single-chip calculator circuits used in Account Manager Calculators.

Don't miss the Corvus CheckMaster introduced by Mostek already in 1975. This rare product retains the balance of your memory even when shut off but uses power-hungry electronics.

If you have additions to the above article please email: joerg@datamath.org.