Engineering Change Order Log for A225 VR14/GT40 Deflection Amplifier

This document is an Engineering Change Order (ECO) log detailing numerous revisions and corrections for the A225 VR14/GT40 Deflection Amplifier between January 1971 and September 1973.

The documented changes primarily focus on:

1. Performance and Stability Improvements: Addressing issues such as incorrect resistor values (R1, R2, R23), inadequate heat sinks, overly sensitive gain potentiometers, module latch-up, cross-over distortion, character distortion (especially on GT40 systems), and ringing in settling time. Corrections involved adjusting resistor and capacitor values (C12, C17), resizing components, and re-routing grounds.
2. Manufacturing and Design Corrections: Implementing layout changes to meet production standards, removing unneeded jumpers, providing for small signal inputs, and replacing metal screws with nylon to prevent shorting.
3. Product Variations and Compatibility: Introducing the A225-YB variation for GT40 systems and ensuring compatibility with new ferrite yokes.
4. Documentation Updates: Redrawing circuit schematics to improve clarity and organization.

Each entry specifies the problem, the correction, and details regarding in-plant and field effectivity, often including estimated installation time and kit contents. These changes collectively aimed to enhance the A225 Deflection Amplifier's reliability, performance, and ease of manufacturing.