Western Auto
Model: Citation (66-4986-7)
Battery: 9 volt
Adapter:
Year: 1978
Chip: TMC0921
Info: If you remove the key-plate known from e.g. the "electronic Wizard" from this Citation you'll get a TI-1050. Everything else is identical, even the back of the calculators tells you the manufacturer Texas Instruments.
Model: Citation (66-4987-5) TI-1025
Battery: 9 volt
Adapter: AC9180
Year: 1977
Chip: TMC0923
Info: With the discontinuation of the TI-1200 family in 1977, Western Auto consequently replaced the M4987 "Citation" calculators and its siblings M4986 and M4988 with products based on the TI-1000 family. While the backside of the revised "Citation" calculator is missing any reference to the previous M4987 designation, sports the sales box a part number 66-4987-5, obviously a reference to the original naming scheme.
Model: Citation (66-4987-5)
Battery: 9 volt
Adapter: AC9180
Year: 1977
Chip: TMS0972
Info:The TMS0952 introduced with the original design of the M4986 was soon replaced with the TMS0972, a pin-compatible design dropping the additional resistors and capacitor and further reducing the manufacturing costs of the M4986 series. This contribution of cost cutting had a side effect for the customer, Texas Instruments decided to use with the TMS0972 an 8-digit LED display instead of the previous 9-digit display. While the 9th (leftmost) digit was originally used only for the negative sign and didn't impact most calculations, should you try this example:
| • 11111111 [-] 23456789 [=] - TMS0952: -12345678 • 11111111 [-] 23456789 [=] - TMS0972: -.1234567 (flashing) |
Model: Citation (66-4988-3)
Battery: 9 volt
Adapter:
Year: 1978
Chip: TMC0921
Info: If you remove the key-plate known from e.g. the "electronic Wizard" from this Citation you'll get a TI-1050. Everything else is identical, even the back of the calculators tells you the manufacturer Texas Instruments.
Model: Citation ( M4986-7 )
Battery: 9 volt
Adapter: AC9180
Year: 1976
Chip: TMS0952
Info: This calculator is identical to the TI-1200 sold under different names from the Western Auto company. The most common names are "Citation" or "M4986". The only difference from the TI-1200 is the wooden template and the missing TI logo.
