Ampro 1500/2000

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High Voltage (HV) Power Supply:

Here is weak point # 2 on the Ampro 2000. The HV supply has caused more grief and despair in Ampro owners when it fails unexpectedly. While they don’t fail very often, they are somewhat hard to find and are very expensive from Spellman, the manufacturer. There are a number of styles of Spellman HV supplies, some of which are interchangeable with each other, most are not. The HV output changed from model to model, as did the power input connections. The model number of each supply is found on the silver sticker pictured above. Common model numbers are X 1685, X 2102 and X 2394. Each HV supply has one or two internal fuses that can be accessed by removing the covers to the power supply. If the internal fuse blows again after replacement, then there’s a problem within the supply. I have had limited success repairing HV supply faults not located in the sealed silicone section of the HV supplies.

Earlier HV blocks had three independent HV output connections that went to the tubes, and contained the focus controls right in the HV block. Later HV power supplies used a separate focus and HV distribution block, undoubtedly to take some of the heat generated within the supply away from the HV components.