The NCR 605 Minicomputer

NCR 605 Diagnostic Tools

The 605 Diagnostic control panel

The diagnostic control panel was connected to an interface card by a ribbon cable.  The 725 had a built in panel but the 726 did not. 

The Tektronix 465 Scope

Data Scope Protocol Analyzer

The early NCR POS systems used a NCR asynchronous poll and select protocol. It was similar to IBM bysync but unique to NCR products.  Later on it became sycn poll and select.      

The ASCII Code Chart 

Without the ASCII code chart the data scope wasn't much help.  In the 70s the data scopes only displayed the ASCII characters and did not provide a detailed display of the protocol information.   This chart has been color coded in yellow to highlight the control characters and coded for the poll and select bits. 

NCR 2151 Repair

In October of 1977 the Bon Marche', one of the first NCR 2151 installations, also became the first NCR customer to maintain their own POS system.  The repair concept was based on the NCR model of test, diagnose, card swap, and adjust at the field level and a centralized rework center to repair the printed circuit cards to the component level.  It was an amazing team of people that serviced the equipment and ran the rework center.  They are some of the most dedicated and smartest technical people that I've ever had the pleasure to work with.

        The the rework center, the heart of the operation 

Three 2151s were dedicated to be used a test fixtures. The boards were repaired using excellent technical diagnostic work and a Fairchild board tester that was programmed for the 2151 boards.  There was a serial number assigned to each board that was repaired and a log kept that described the fault and repair on each board.  The accuracy of repair was very high with very few returns.  Repairing the boards was a huge accomplishment that required countless hours of research and extraordinary talent.                 

Terminals awaiting repair in depot maintenance

Depot maintenance was provided for stores that were in Eastern Washington, Idaho, Oregon, Montana and Utah. 






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