7A18

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The Tektronix 7A18 is a general-purpose 75 MHz dual-trace vertical plug-in for 7000-series scopes. Model 7A18N is identical except it omits the readout circuits.

Option 06 (first offered in 1975 catalog) adds offset voltage controls giving ±200 Div offset range. This option replaces the IDENTIFY buttons with DC offset controls and adds a fourth "DC offset" position to the input coupling switch.

The 200 MHz 7A26 and 400 MHz 7A24 share the same front panel layout and operation.

The 7A18 uses a discrete front-end followed by M36 channel switch ICs for the vertical and trigger signals.

Specifications

Input impedance 1 MΩ // 20 pF
Deflection 5 mV/div to 5 V/div in 1–2–5 sequence, 2%
Bandwidth 0 – 75 MHz (DC), 10 Hz – 75 MHz (AC)
Noise < 300 μV in 5 mV/Div
Option 06 offset range ±200 Div equiv. from ±1 V in 5 mV/Div range up to ±200 V in 1 V/Div range (above that limited by maximum input voltage)
Features
  • Mode: CH1 only, CH2 only, Add CH1+CH2, Alternating, Chopped. CH2 can be inverted.
  • Input sockets with contact ring for probe ×10 / identify information
  • No bandwidth limiter switch
Weight 1.4 kg

Prices

Year 1971 1976 1980 1984 1990
Catalog price $535 $615 $915 $1,250 $1,790
2018 value $3,300 $2,700 $2,770 $3,000 $3,420

Repair issues

The pins of the attenuator modules are connected to conductive traces on the ceramic substrate inside by low-temperature soldering, which can go bad. Re-seating the module can temporarily restore the internal contact but will usually not fix the problem permanently. Repair is possible by opening the click-locked lid and carefully resoldering.

Pictures

Option 06

Custom ICs used in the 7A18

Page Class Manufacturer Model Part nos Description Designers Used in
155-0022-00 Monolithic integrated circuit Tektronix M036 155-0022-00 155-0022-01 analog multiplexer Gene Andrews 335 468 2220 2221 2230 7403 7503 7603 7613 7623 7623A 7633 7704 7704A 7834 7844 7854 7912AD 7912HB 7904 R7903 7904A 7934 7A12 7A18 7D12 NT-7000 P7001