661 Series plug-in interface

The Tektronix 661 oscilloscope mainframe takes two plug-ins: the sampling plug-in (e.g., 4S1) and the timing plug-in (e.g., 5T1).

Overview

The sampling plug-in interfaces with the Type 661 mainframe via two multi-pin connectors:

P1 Power Connector
P2 Readout Connector

The timing plug-in interfaces with the Type 661 mainframe via two multi-pin connectors:

P3 Digital Readout Connector
P4 Interconnecting Plug

There is also a pair of coaxial cables terminating in Gremar connectors connecting the sampling plug-in to the timing plug-in. The coaxial cables are part of the mainframe, but are not electrically connected to the mainframe. They just pass through.

Sampling Plug-in Interface

P1 Power Connector

Pin	Function	Comment
1	unused
2	unused
3	−19 V
4	−25 V
5	−100 V
6	Staircase In
7	Ground
8	B Out To Horiz
9	Ground
10	B Vert Out
11	A Vert Out
12	Ground
13	unused
14	unused
15	+300 V
16	unused
17	+100 V
18	+19 V
19	Staircase Out
20	ground
21	blanking
22	ground
23	ground
24	Vert Sig Out

Pin group function legend

DC power

AC and heater power

Deflection and Trigger Signals

Control Signals

Timing Plug-in Interface