Description
IBM 3178 Coax Logic Board 6052121 F-6052121 GC4-94V1 Monochrome Terminal Card
The IBM 6052121 is the coax logic board for the IBM 3178 Monochrome Display Terminal, a member of IBM's 3270 Information Display System family. This card handles the coaxial communication interface and display logic that connects the 3178 terminal to an IBM host controller, translating coax-delivered data streams into the character output shown on the terminal's screen. The board carries assembly number 865232B and is date-coded 8-1-84, placing it in the early-to-mid 1980s production era of IBM's SNA/3270 terminal ecosystem.
Specifications & What's Included
- Manufacturer: IBM
- Part Number (P/N): 6052121
- Secondary Part Number: F-6052121
- Board Assembly: 865232B
- Board Revision / Date Code: GC4-94V1, dated 8-1-84
- Compatible Terminal: IBM 3178 Monochrome Display Terminal
- Terminal Family: IBM 3270 Information Display System
- Form Factor: Single-slot card/module with integrated bracket
- Bracket Ports: Port 2 — D-sub connector; Port 4 — BNC coaxial connector; Port 5 — D-sub connector
- PCB: Green multi-layer board populated with logic ICs, memory chips, and support components
- Included: Logic board with bracket only; no terminal enclosure or cables included
Applications
The IBM 3178 was a low-cost, compact monochrome display terminal introduced in the early 1980s as part of IBM's 3270 family, which was IBM's dominant terminal platform for connecting users to mainframe and midrange hosts running CICS, TSO, VM/CMS, and similar environments. The 3270 coaxial terminal architecture used a dedicated coax cable running from each terminal to a cluster controller (such as the IBM 3174 or 3274), which in turn connected upstream to an IBM System/370, System/3xx, or AS/400 host. The coax logic board is the heart of that connection — it implements the 3270 data stream protocol, manages screen buffer logic, and drives the monochrome CRT display. This type of board is sought today primarily for repair and restoration of surviving 3178 terminals in legacy IBM computing collections, museum exhibits, and installations that still operate original 3270 infrastructure. Given the age and scarcity of 3178 hardware, replacement logic boards are difficult to source, making this a useful spare or donor component for maintainers of vintage IBM terminal equipment.
This IBM 3178 Coax Logic Board (P/N 6052121) has been inspected and is in good used condition. It was pulled from a working environment where it was previously in use. The PCB shows normal age-related patina consistent with a board dated 8-1-84; no cracked traces, burnt components, or physical damage are visible in the photos. The bracket and its three ports (two D-sub and one BNC) appear intact and undamaged. Please view our photo set and contact us if you have any questions. Please note: We have multiple units in stock — yours may not be the one shown in the photos, however, it will be similar in condition and function.
Warranty Information
Additional Information
Brand: |
IBM |
Model: |
3178 |
MPN: |
6052121 |
Secondary Model: |
F-6052121 |
Board Assembly Number: |
865232B |
Board Revision / Date Code: |
GC4-94V1, dated 8-1-84 |
SKU: |
18349 |
Type: |
Coax Logic Board / Terminal Controller Card |
Compatible With: |
IBM 3178 Monochrome Display Terminal |
Compatible With 2: |
IBM 3270 Terminal Family |
Interface Type: |
Coaxial (BNC), D-Sub connectors |
Connector Types: |
BNC coax port, two D-sub connectors (ports 2 and 5) |
Form Factor: |
Card / Module with bracket |
Condition: |
Used – Pulled from Working Environment |
Country/Region of Manufacture: |
United States |
Seller Notes: |
Board only; no terminal enclosure included. Three bracket ports visible. |
Condition Notes: |
IBM 3178 Coax Logic Board 6052121 pulled from a working environment, inspected and in good used condition. PCB shows normal age wear; no visible damage. Bracket and all three ports appear intact. |
California Prop 65 Warning: |
WARNING: This product can expose you to chemicals including lead and lead compounds, and DEHP (a phthalate), which are known to the State of California to cause cancer and birth defects or other reproductive harm. Go to P65Warnings.ca.gov |