Gold-Cap, CNC And Telecom Boards: Parts And Uses

Gold-Cap, CNC And Telecom Boards Come From Machine Tools, Industrial Controls, Computers, And Communications Equipment. Here Is What Their Components Do And How The Main Board Types Differ.

A Board That Ran A Milling Machine Has A Different Job From A Card That Carried Network Traffic. Yet Both Can Have Gold-Plated Contacts, Ceramic Chips, And Rows Of Pins. Those Shared Features Explain Why They Often Appear Together In Electronic Scrap Lists.

This Guide From Recycle Circuit Boards Covers The Hardware Behind The Names. A Wire-Wrap Backplane Uses Individual Wires Wrapped Around Long Posts To Make Connections.

Gold-Cap Circuit Boards

The Name Refers To Boards Carrying Chips With Gold-Colored Metal Lids, Often On Ceramic Packages. The Cap Is Part Of The Chip Package. Underneath It Is The Semiconductor Device That Performs The Electronic Work.

These Packages Can Turn Up In Older Computer Assemblies, Industrial Controls, And Communications Hardware. A Ceramic Package Alone Does Not Identify The Board’s Job. You Need To Consider The Rest Of The Assembly And The Equipment It Came From.

Why Put A Metal Lid On A Ceramic Chip?

The Package Protects The Device Inside. A Hermetic Seal Limits The Entry Of Moisture And Other Contaminants. Kyocera Describes Both Soldered And Welded Metal-Lid Designs In Its Explanation Of Hermetic Packaging.

A Gold-Colored Cap Is Not Necessarily Solid Gold. Intel’s Packaging Databook Describes One Construction Using A Gold-Plated Nickel-Iron Alloy Lid And A Gold-Tin Seal. That Is A Specific Package Design, Not A Formula For Every Gold-Cap Chip. See Intel’s Ceramic Packaging Details, Pages 3-20 And 3-21.

Gold-Edge Circuit Boards

Gold-Edge Boards Have Plated Contact Pads Along An Edge That Fits Into A Connector. The Pads Are Often Called Gold Fingers. They Carry Electrical Connections Between The Removable Card And The Rest Of The System.

• Computer Expansion Cards
• Industrial Plug-In Cards
• Memory Modules
• Some Communications And Test Equipment Cards

Unlike A Row Of Separate Metal Pins, Edge Contacts Are Part Of The Board Itself. TE Connectivity Lists Card-Edge, Board-To-Board, And Backplane Connections As Different PCB Connector Families.

Why Use Gold On Contacts?

The Finish Helps Maintain A Reliable Electrical Connection. Connector Designs May Use Gold At The Mating Surface And A Different Finish On The Solder Tail. Samtec Explains This Selective Plating In Its Contact And Terminal Design Guide. The Visible Gold Is A Surface Layer; The Size Of The Yellow Area Does Not Tell You Its Thickness.

CNC Control Boards

CNC Means Computer Numerical Control. These Systems Run Programmed Machine Movements, Such As Positioning A Cutting Tool On A Mill Or Moving The Tool And Workpiece On A Lathe.

A CNC Cabinet Can Contain Several Types Of Electronics. The Main Controller Processes The Machining Program. Motion-Control Electronics Coordinate The Axes. Input And Output Circuits Connect The Control To Machine Signals. Servo Drives Supply Controlled Power To The Motors; They Are A Different Part Of The System From The Main Logic Board.

• CNC Mills And Machining Centers
• CNC Lathes And Turning Centers
• Laser-Cutting Machines
• Other Programmed Motion Equipment

FANUC’s CNC System Overview Shows Controls, Motors, Drives, And Operator Interfaces As Related Parts Of A Machine-Control System. A Board From That Cabinet Is Not Automatically A Gold-Cap Board. Its Components Depend On The Control Design And Generation.

Industrial Automation Boards

Industrial Automation Electronics Connect A Program To A Physical Process. A PLC, Or Programmable Logic Controller, Reads Inputs, Runs Its Control Program, And Updates Outputs.

For Example, A Sensor Can Report That A Part Has Reached A Position. The Controller Uses That Input To Decide When To Operate An Output. An I/O Card Provides The Connection Between The Controller And Field Devices; It Does Not Have To Look Like A Computer Motherboard.

• PLC Processor Modules
• Digital Input And Output Cards
• Analog Measurement And Control Modules
• Communications Modules
• Specialized Motion Or Counting Modules

These Assemblies Appear In Machine And Process-Control Cabinets. Some Are Inside Individual Plastic Modules With Removable Wiring Terminals. Siemens’ SIMATIC S7-1500 Hardware Overview Shows How CPUs, Signal Modules, Communications, And Other Functions Fit Into A Modular System.

Wire-Wrap Pin Boards

Wire-Wrap Construction Uses Wire Wound Tightly Around Terminal Posts To Make Connections Without Solder At The Wrap. Look For Long Posts With Several Tight Turns Of Wire Near Their Bases. Individual Wires Run Between Those Posts.

This Is Different From A Modern PCB Where Most Connections Run Through Copper Traces On Or Inside The Board. A Wire-Wrapped Assembly Can Have A Dense Web Of Wires On Its Back. Long Pins Without Wrapped Wires, By Themselves, Do Not Prove That It Is A Wire-Wrap Board.

Jonard Describes The Result As A Gas-Tight, Solderless Connection In Its Wire-Wrapping Tool Documentation. For A Historical Example Of Wired Computer Interconnections, The Computer History Museum Shows The PDP-1 Backplane, Which Connects The Machine’s Circuit Modules.

Pin Boards

In Scrap Descriptions, A Pin Board Usually Means An Assembly With Many Connector Pins. The Name Describes What You Can See, Rather Than A Single Electronic Function.

Those Pins May Connect Removable Cards, Cables, Or Other Assemblies. A Pin Board Can Also Be A Backplane. If Wires Are Wrapped Around Its Posts, It May Fit The Wire-Wrap Description Too. The Categories Can Overlap.

Look At The Whole Connector, Including Its Plastic Housing And The Opposite Side Of The Board. A Gold-Colored Contact Surface Does Not Mean The Entire Pin Is Gold. For Example, This TE Pin Contact Uses A Brass Contact Body With Gold Contact Plating. Other Contacts Use Different Base Metals And Finishes.

Backplane Boards

A Backplane Provides Connections For Several Modules In A Chassis. Instead Of Wiring Every Card Directly To Every Other Card, The Modules Plug Into A Shared Interconnection Assembly.

• Modular Computer And Expansion Chassis
• Server And Storage Equipment
• Telecom Shelves
• Industrial Control Racks

Repeated Connector Positions Are A Useful Clue. A Backplane May Have Far Fewer Visible Chips Than The Cards Plugged Into It Because Its Main Job Is Interconnection. That Does Not Make It An Unfinished Board.

Backplanes Are Not Always Conventional PCBs. Cisco Documents A Passive Cable Backplane In Its C9610 Chassis Architecture. This Is Why The Equipment’s Construction Matters More Than Assuming Every Chassis Contains The Same Kind Of Backplane.

High-Grade Telecom Boards

Telecom Boards Handle Communications Tasks Such As Connecting Interfaces, Processing Traffic, Or Controlling A Chassis. In A Modular Router, Different Cards Can Have Very Different Jobs.

For Example, Cisco’s CRS Documentation Describes Line Cards That Process And Queue Packets, Alongside Route-Processor And System-Control Functions. The Details Are In The CRS Line-Card Chassis Description.

High Grade Is A Scrap-Buying Description, Not A Network Performance Rating. In A Buyer’s Material List, It Often Points To Boards With A Concentrated Mix Of Integrated Circuits And Plated Connectors. It Does Not Mean That The Board Still Works Or That It Supports A Particular Network Speed.

Lower-Grade Telecom Boards

Boards From The Same Communications System Can Have Very Different Component Mixes. A Board With Fewer Chips, More Bare Area, Or A Larger Share Of Heavy Hardware May Be Treated Differently From A Densely Populated Processing Card.

The Word Lower Refers To The Scrap Category. It Does Not Mean The Manufacturer Built An Inferior Product. A Circuit Designed For A Different Job Can Need Fewer Integrated Circuits And More Space For Other Components.

Boardsort’s Category Discussion Describes Chip Density, Connectors, And Other Board Weight As Factors In Telecom Sorting. That Discussion Helps Explain The Trading Language. It Is Not A Universal Engineering Standard Or A Gold-Yield Table.

Questions That Come Up When Identifying These Boards

Can One Board Fit More Than One Description?

Yes. A CNC Board Can Have Gold Edge Contacts And Ceramic Chips. A Telecom Backplane Can Have Rows Of Pins. Start With What The Board Did, Then Describe Its Components And Connections.

Are All Ceramic Chips Gold-Capped?

No. Ceramic Describes The Package Material. Lids And Sealing Methods Vary. Some Packages Use Ceramic Lids, While Others Use Metal. The Body And Lid Are Separate Features.

Can You Tell The Gold Content From A Photo?

A Photo Can Show Plated Contacts And Package Types. It Cannot Measure Plating Thickness Or Reveal Every Internal Material. Two Similar-Looking Parts Can Use Different Constructions, So Appearance Alone Cannot Provide A Reliable Gold Weight.

Is A Populated Board The Same As A Bare PCB?

No. A Populated Board Has Components Installed. A Bare PCB Has The Board’s Conductive Connections And Mounting Features Before Those Components Are Added. A Backplane With Few Chips May Still Be A Complete Assembly With Its Connectors Installed.

Have Boards From Retired Equipment?

Recycle Circuit Boards Buys Circuit Boards And Electronic Components, Pays Cash, And Arranges Pickup At Your Location. We Handle The Boxing And Loading. Send Photos Of The Lot, Your City, And An Approximate Amount To Email, Or Call.

For The Material Categories We Discuss With Sellers, See Our Gold-Cap And Industrial Board Purchasing Page. For Other Computer Parts And Electronics, Use The Complete Board-Type Directory.

Recycling Industrial And Telecom Board Lots

A Control Cabinet Can Contain Several Different Materials: Logic Boards, Power Boards, Backplanes, Wiring And Steel Hardware. A Box Of CNC Cards Is Easier To Evaluate When The Source Equipment Is Known. Separate Loose Boards From Heavy Cabinet Parts If They Are Already Removed, And Describe Complete Assemblies As Complete Assemblies.

Some Older Control Cards Still Have Repair Or Spare-Part Value. Check That Possibility Before Treating Every Retired Board As Scrap. For Material That Is Ready For Recycling, Clear Photos Of Both Sides Help Show Ceramic Chips, Connector Rows And Attached Metal. A Gold-Colored Lid Or A Dense Row Of Pins Does Not Establish A Recoverable Gold Weight.

During Recycling, Electronics Are Sorted And Sent Through Processes That Separate And Recover Materials. The Mix Of Copper, Other Metals, Components And Board Substrate Matters More Than The Color Of The PCB. Tell Recycle Circuit Boards Whether Your Lot Comes From Machine Maintenance, A Telecom Upgrade Or A Parts-Room Clearout So We Can Discuss The Material And Pickup Access.