My collection of NCR 315 parts.

I was a Computer Operator on this machine in 1971 and removed these parts when it was replaced 

by a UNIVAC 9380. (9400 series)

NCR 315 Computer Room

I took this picture a few months before the 315 was shut down and sold for scrap. In 1965 this computer cost 300,000. About 700 NCR 315 systems were delivered between 1960 -1967.

NCR 315 Handbook (PDF)


Scrapping the 315


Rotron Muffin 4 cooling fan

(on the tape handler)


Dismantling the NCR 315.

(Between the tape drives and CRAM unit is a DEC PDP 11/45 printer.)



Ferrite Core Memory Array 







Memory board with protective cover.

Ferrite Core Memory Array


Memory boards slotted into the main board


Complete memory board 625 bytes


PCB #395   Auxiliary memory sense wire amplifier

PCB #146   Memory Timing No. 3

   PCB #39    Memory Logic.

Memory Wiring Loom


Console Display


NCR 315 Master Console


The numbered buttons on the right are the equivalent of function keys on modern PCs. New Main and New Aux allow direct access to the memory. Compute will start the program currently loaded and Halt will bring program to an orderly stop. I believe our NCR 315 had 5,000 slabs of memory. Communication with the Operator was via a teletype console.



NCR 315-100 Operator Console

Picture taken in 1976 a few months before the 315 was scrapped.



NCR 315 Data Processor, Instruction Format, Instruction Groups, Mnemonics, Codes & N-Register Settings


NCR 315 Advertisements 1962



C.R.A.M.  (353-3)

Card Random Access Memory

Control panel from the NCR 315 CRAM unit.

Introduced by NCR in 1962 the CRAM was the first mass storage device.

It offered reliable random access storage at a time when magnetic tapes were the primary storage medium. Up to 16 CRAM units could be online.

Each CRAM unit held one 5.5MB cartridge that contained 256 mylar, 3x14" cards with a magnetic recording surface. The cards were suspended from eight rods, which were selectively moved to release a specific card. The card was pulled out, wrapped around a rotating drum and read or written. The drum (in the 353-3) had 56 fixed read / write heads.

Close up of control panel



CRAM Switches

Local = Offline

Operate = Online

CRAM Operating Instructions 


                                                                                                                                                     Cutting a new CRAM card.

                                                                              We did not have one of these devices, so with the old Cram card as a template, used scissors to remove the tabs .


           Cram Deck Structure (353-3).                                                    Recreating a CRAM card using CRMX.             





Teletype Print Head

Teletype print head and NCR teletype paper rolls from the Operator Console.


All communication with the 315 was via the console teletype.



Various Parts

The capacitor is rated at 4,000 MFD μF microFarads.



Gold plated switch contacts


Various PCBs

All PCB contacts are gold plated.








  PCB #26      Enable Driver                   PCB #26      Enable Driver                    PCB #36           Relays 

Pre Amps and Gates

Skew Test Card


    Dialco neon bulbs from the console displays.                                             

Magnetic Tape Handler

334  131/132

Data Transfer Rate - 16,500 slabs-per-sec.


7 track read / write head from NCR 315 tape handler.

Unused and in original box.  (we had 9 track handlers installed)

Tape Handler Switches & Indicators

556 ODD = Density and Parity


                                                                                                                                                   Tape Head Connector

Tape loop roller & pinch roller.                    Hardware Operating Magnetic Tape

Paper Tape

Paper tape was used as a fast method (2,000 cps) of inputting data from the very first computers. The Colossus at Bletchley Park used paper tape for input.

Paper Tape Reel

Paper Tape Reader Guide Block


Control Panel PPTR and PPTP

Paper tape reader and paper tape punch control panel.

Reel from the Paper Tape Punch


                 NCR 315 Documentation                           Language H 1962 (PDF)



Micro Switches

Typical illuminated micro switch used on the NCR control panels.

Each switch has sockets for up to 4 bulbs.


NCR Line Printer (340)

Engineers Diagnostic Panel 

1976 Calendar printed on the NCR line printer. →→


Paper stretch control knob.


VFU tape contact drum & idler spools.

The VFU tape controlled slew length (length of form).


Paper feed tractor plate.                   Printer unit number switch.


PCBs from the Central Processor




Shift & Clear Driver

 PCB #219      Flip-Flop No. 1                                          Flip Flop                             PCB #137

Solenoid Driver Control

                       Adder No. 5                      PCB #249   Read Write Switch No. 4      PCB #260     Holdover No. 6 

                                    Filter   PCB #381           Clock                             PCB #115  Low Power Clock No. 3                        Output Driver No. 2

Resistor Colour Codes



Resistor Colour Code Chart

                      Shift Register

NCR Promotional 315 Pictures

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