In many PCB projects, test points are treated as a minor detail.
If they are added at all, they are often squeezed in at the very end of layout, after routing, placement, and mechanical constraints are already fixed.
In production, this decision has far-reaching consequences.
At Comtec Labs, test-related issues are one of the most common causes of:
Slow production ramp-up
Increased test cost
Difficult troubleshooting
Field failures that could have been caught earlier
This article explains why test points are a critical part of Design for Manufacturability (DFM) and Design for Testability (DFT), and why small decisions here have an outsized impact on yield and quality.
Why Prototypes Hide Testability Problems
In early builds, boards are often tested manually.
Engineers probe signals directly, connect flying wires,
and tolerate awkward test setups.
This flexibility disappears in production.
Once volumes increase:
Manual probing is no longer viable
Test time must be predictable
Coverage must be consistent
Designs that “worked fine” in prototypes often fail to scale because test access was never designed in.
What Test Points Actually Enable
Well-designed test points enable:
Faster in-circuit testing (ICT)
Reliable functional testing
Automated test coverage
Faster fault isolation
Lower rework cost
Without proper test access, manufacturers are forced to choose between reduced coverage or increased cost.
Common Test Point Mistakes
Typical issues include:
Too few test points
Test points placed under components
No power or ground access
Inconsistent spacing for probes
No consideration for test fixtures
Each of these increases test complexity and reduces production efficiency.
Designing Testability From the Start
Good DFT begins at schematic and placement stages.
Key questions include:
What needs to be tested in production?
Which nets require access?
What test method will be used?
How will faults be diagnosed?
Answering these early makes layout easier—not harder.
DFM, DFT, and Long-Term Quality
Testability is not about catching mistakes. It is about controlling variation.
Designs with good test access:
Ramp faster
Produce more consistent quality
Are easier to support over their lifetime
Test points may be small, but their impact is enormous.
Ready to Reduce PCB Surprises?
If you’re navigating complex requirements, tight schedules, or production risk, Comtec Labs offers a full suite of services to streamline your workflow:
PCB design service
PCB prototyping service
PCB component sourcing
PCB component assembly
PCB testing service
PCB repair and modifications
Printed circuit board production
PCB mass production