125

Manuals – Specifications – Links – Pictures

The Tektronix 125 is a power supply introduced in 1961 for the Type 122 preamplifier. The 125 runs on wall power (mains) and provides three regulated outputs:

• +135 V_DC at 0-20 mA, 1 mV ripple, tube-based regulation
• -90 V_DC at 0-20 mA, 1 mV ripple, tube-based regulation
• -6 V_DC at 0.7-4 A, 4 mV ripple, transistor-based regulation

The +135 V section contains an OG3 voltage reference tube. The -90 V and -6 V sections use the +135 V supply as their reference. All power rectification is done with semiconductor diodes.

A calibration fixture, the 067-0528-00, exists for testing the 125.

The 125, like the 122, appears in three form factors:

• 125 (standard, vertical orientation, no mounting ears)
• RM125 (rack mount, horizontal orientation, with wide front panel for mounting mounting in a standard 19" rack, later called "R125")
• FM125 (frame mount, vertical orientation, for use in the 014-002 mounting frame, later called "F125")

Pictures

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  Schematic

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  RM125 Front

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  RM125 Internal Top View

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  RM125 Internal Underside

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  RM125 Rear

Some Parts Used in the 125

Part	Part Number(s)	Class	Description	Used in
6G11	154-0660-00	Vacuum Tube (Pentode)	double sharp cut-off beam power pentode	125 • 132 • 519 • 067-0502-01 • 050-0551-00
6GE8	154-0260-00	Vacuum Tube (Triode/Pentode)	triode-pentode combo	125 • 132 • 560
7734	154-260 • 154-0260-00	Vacuum Tube (Triode/Pentode)	triode-pentode combo	125 • 132