500 Series plug-in interface
The plug-in interface of the 500-series scopes is a single 16-pin Amphenol connector.
|1||+Signal||100 mV/cm, bias +67.5 V ±2%|
|3||−Signal||100 mV/cm, bias +67.5 V ±2%|
|4||Int Trig GND|| 544, 546, 547, 549,|
556, late 555 only
|5||Int Trig +|| 544, 546, 547, 549,|
556, late 555 only
|6||Sawtooth||556 only, others n/c|
|7||Slave Pulse out||547 only|
|8||Multi-trace sync|| Cathode; grounded by CA,|
M etc. in Alt Trace mode
|9||−150 V||min. 3.8 mA, max. 60 mA|
|10||+100 V||min. 4.5 mA, max. 50 mA|
|11||+225 V||min. 16 mA, max. 75 mA|
|12||+350 V||min. 0 mA, max. 20 mA|
|13||6.3 VAC|| plug-in AC heater supply,|
max. 2.8 A
|14||6.3 VAC||return for pin 13|
|15||+75 V|| min./max. 150 mA for DC|
series heaters and LV supply
Pin group function legend
DC power and ground AC and heater power Deflection and Trigger Signals Control Signals
Internal Trigger signal
In these scopes, changing the vertical position control on the plug-in interacts with the trigger level setting if the scope is set to a DC trigger mode.
In somewhat later 500-series systems (e.g. Type 547), the plug-in (e.g. Type 1A1) provides the mainframe with a separate trigger signal on pin 5 whose DC level is not affected by the vertical position knob. In multi-trace setups, this allows consistent triggering from a specific input channel independent of which channel is currently being drawn on CRT.
For backward compatibility, the 547-era scopes have two types of INT triggering, taking the trigger signal either from the main vertical plug-in output (1/3), or the trigger output (5).
Although the Type 1A1 has two input channels, they are not identical - the pin 5 internal trigger signal is always taken from channel 1. Even later 500-series plug-ins (e.g., the Type 1A4), have a knob for the selection of which input channel's signal supplies the trigger signal. |}