MS 4TR Board Mount Axial Fuse - Equivalent & Substitute Parts

Part Overview

The MS 4TR is a 4A 125VAC/VDC board mount axial fuse manufactured by Bel Fuse Inc. This component is classified as obsolete, making equivalent substitute parts necessary for ongoing design support and procurement. The MS 4TR serves as a protective device in low-voltage AC/DC circuits requiring slow-blow response characteristics and through-hole mounting configuration.

Substiute Parts

MS 4TR

Bel Fuse Inc.In Stock: 1107MS 4TR Datasheet

Current PartRFQ

0473004.MRT1L

LittelfuseIn Stock: 17760473004.MRT1L Datasheet

DirectRFQ

0473004.YRT1L

Littelfuse Inc.In Stock: 84250473004.YRT1L Datasheet

DirectRFQ

0471004.NRT1L

Littelfuse Inc.In Stock: 642710471004.NRT1L Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the MS 4TR are classified into two categories based on electrical and mechanical compatibility:

Direct Substitutes (Littelfuse PICO® II 473 Series):

• 0473004.MRT1L
• 0473004.YRT1L

These parts maintain identical electrical specifications: 4A current rating, 125VAC/125VDC voltage ratings, slow-blow response, 50A breaking capacity at rated voltage, and equivalent operating temperature range. Physical dimensions are comparable (0.135" Dia x 0.280" L vs. 0.125" Dia x 0.280" L), permitting direct board-level substitution. Both are active products with current manufacturing status.

Similar Substitute (Littelfuse PICO® II 471 Series):

• 0471004.NRT1L

This part shares identical electrical ratings (4A, 125VAC/125VDC, slow-blow, 50A breaking capacity) and operating temperature range. Physical dimensions differ slightly (0.110" Dia x 0.280" L), requiring mechanical verification for board layout compatibility. This part is active and widely available.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Preferred): Select either 0473004.MRT1L or 0473004.YRT1L from the Littelfuse PICO® II 473 series. Both parts are active products with identical electrical specifications and comparable physical dimensions to the MS 4TR. The 0473004.YRT1L offers higher inventory availability (8376 pcs) compared to 0473004.MRT1L (1727 pcs). Both carry CSA and UR certifications, maintaining compliance with the original part's approval standards.

For Space-Constrained Applications: The 0471004.NRT1L (PICO® II 471 series) provides an alternative when board layout permits a smaller diameter component (0.110" vs. 0.125"). This part maintains all critical electrical parameters and is the most widely available option (64200 pcs). Mechanical board layout verification is required due to dimensional differences.

Compliance Considerations: All substitute parts are RoHS3 compliant and carry active product status, ensuring long-term availability and manufacturing support. The MS 4TR's obsolete status necessitates transition to one of these active alternatives for new designs or ongoing production support.

Frequently Asked Questions (FAQ)

Q: Can 0473004.MRT1L and 0473004.YRT1L be used interchangeably? A: Yes. Both parts are from the Littelfuse PICO® II 473 series with identical electrical specifications, voltage ratings, current ratings, and physical dimensions. Selection between them depends on packaging preference (Cut Tape) and inventory availability.

Q: What is the primary difference between the PICO® II 473 and PICO® II 471 series substitutes? A: The PICO® II 471 series (0471004.NRT1L) has a smaller diameter (0.110" vs. 0.135"), resulting in lower DC cold resistance (0.012 Ohms vs. 0.0194 Ohms) and different melting I²t characteristics (10.6 vs. 35). All electrical ratings remain identical. Physical board layout compatibility must be confirmed before selection.

Q: Are there any certification differences between substitute options? A: The PICO® II 473 series parts carry CSA, PSE, and UR certifications. The PICO® II 471 series carries PSE and UR certifications. The original MS 4TR carried CE, CSA, and cURus certifications. Application-specific regulatory requirements should determine final selection.

Q: Can the MS 4TR be directly replaced without board redesign? A: The PICO® II 473 series (0473004.MRT1L and 0473004.YRT1L) are direct replacements with minimal dimensional variation. The PICO® II 471 series requires mechanical verification due to diameter differences but maintains electrical compatibility.

Q: What is the impact of DC cold resistance differences on circuit performance? A: DC cold resistance affects voltage drop under normal operating conditions. The substitute parts exhibit lower cold resistance (0.0194 Ohms for 473 series, 0.012 Ohms for 471 series) compared to the MS 4TR (0.041 Ohms), resulting in reduced power dissipation and improved thermal performance in DC applications.