Nicolet 526

The Nicolet 526 is a signal averager that is used in a modified OEMed Tektronix 5110 (5103N/D10) mainframe. The modifications to the mainframe performed by Nicolet include

• adding a perforated panel for fan cooling via the bottom panel of the scope,
• adding a 12-pin connector on the rear panel of the scope
• connected the 12-pin connector to the interface board, connector J604.

The 526 has its own +5V regulated rail. An external source of +7V unregulated DC is routed from thee 12-pin rear connector to the mainframe interface board, and into the plug-in. An LM323 +5V three-terminal regulator is the source of the +5V rail within the Nicolet 526. (Even though the input is marked "+7 UNREG" on the board, it should probably be +7.5V minimum, per the LM323 datasheet.) Since the LM323 is rated for 3 amperes, it is unlikely that the plug-in sinks more than that from the "+7 UNREG" input.

Mechanically, the Nicolet 526 is a three-bay 5000-series plug-in. It mates with the center-bay plug-in connector. The Nicolet 526 is made of four boards and a backplane. Connection to the Tektronix mainframe is done via thee backplane. The four boards are:

• ADC and Register
• Address
• Control
• Memory

The design makes heavy use of 7400-series digital logic in DIP packages. The printed circuit boards are two-layer. The memory is an array of Fairchild 2102DC MOS 1k x 1 static RAM ICs, DIP, soldered in place.

The wires connecting the backplane board on the 526 to the mainframe interface connector on the 526 are labeled:

• H LOCK TRIG (white w/ black stripe), pin 27B of the plug-in connector
• TRIGGER (light violet) 26A
• RO TRIG (violet) 26B
• Y LOCK IN (blue) 25B
• FID SIG (green) maybe "FID" stands for "Free Induction Decay" in NMR? 24B
• SIGNAL (brown) 23A
• RO STUS (yellow) 23B
• +7 UNREG (black), pin 22A and 22B of the plug-in connector
• +7 UNREG (black), pin 22A and 22B of the plug-in connector
• GND (white) 14A and 14B
• GND (white) 14A and 14B
• -VERT SIG (white w/ red stripe) 13B
• +VERT SIG (white w/ brown stripe) 13A
• -HORIZ SIG (white w/ orange stripe) 11B
• +30 (red) 5A
• -30 (orange) 5B
• 11A is jumpered to 14B at the male plug-in connector of the 526.

The 12-pin rear-panel connector has its pins numbered on the inside of the connector.

Pin	Function	Comment
1
2
3
4
5
6
7
8
9
10	Ground
11
12

• 

  Front

• 

  Top

• 

  Left

• 

  Right

• 

  Bottom

• 

  ADC and Register

• 

  ADC and Register

• 

  Address Board

• 

  Address Board

• 

  Control Board

• 

  Control Board

• 

  Memory

• 

  Memory

• 

  Rear

• 

  Top front

• 

  Right front

• 

  Bottom front

• 

  Mainframe rear connector internal

• 

  Mainframe rear connector external

• 

  Mainframe rear connector to J604