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ABB, Inc. in partnership with D&D Enterprises, LLC. introduces the latest design as the Sole Source of the TD Amplifier for the Series II/III Rolls-Royce T56 Engine. Providing improvements that yield increased reliability & safety, ease of maintenance, future sustainability, and reduced life-cycle costs.

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TD AMP Drop-In Replacement

50% less Depot Level MX 

Already in Use by 14 operators, including USAF

• Replaces all Series II/III TD AMPs
(Round or Square)

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Old Square TD AMP

• Potentiometers with no reference dial or stops

• Increased MX costs & reduced aircraft readiness due to field adjustment errors  

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New TD AMP Updates 

• DROP-IN REPLACEMENT for all Series II/III TD AMPs (Round or Square)

• Compliant with US Air Force Recommendations for Improved Safety

• BIAS knob has been plugged

• Slope knob has become a Temp selector between 971C & 1077C

• Norm knob has become the Slope Adjustment ± 20˚

• Start knob has been plugged


Improved Safety & Reliability

Eliminates un-commanded engine power rollback

withstands intermittent aircraft low voltage as low as 35vac

50% reduction in repair costs and downtime

Flexible, Customizable Integration

Drop-in Replacement, no aircraft modification required

Use any combination of old and new PNs on each aircraft for easy, phased fleet upgrades

- No need to replace all 4 TD amps at once






839966-1 6887091 6859769 5502636-1 5502636-2

6876338 23009257 23052609 23059687 J23059687

PN: 23089510   /   
NSN 5996-01-628-4657

with the following Part Numbers:

Future Sustainability 

Mitigate Obsolescence for continued support of parts & repairs

Increased cost savings with aircraft readiness and reduced life-cycle costs

Improved Safety & Reliability
Eliminate uncommanded engine power rollback

• Low voltage immunity circuit eliminates the risk of four-engine power rollback due to intermittent aircraft power supply to TD AMP

• Reliable operation down to 35VAC


50% Reduction in Repairs

Simplified Field Adjustments

• Fool-proof Slope adjustment ± 20˚ on 971C/1077C setting

• Normal adjustment has been replaced with selector switch between Series II/III engine settings

• BIAS & Start manual adjustments have been eliminated

• Increased cost savings & aircraft readiness


Drop-In Replacement

• No aircraft modification required

• Replaces all Series II/III TD AMPs (Round or Square)


Future Sustainability

• Mitigate Obsolescence for continued support of parts & repairs

• Old PN Upgrade Modification – Uneconomical


Flexible Upgrade Integration

• Operators can use with any combination of old and new PNs on each aircraft allowing for easy, phased fleet integration  

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