The Tektronix 7603 is a general-purpose 100 MHz non-storage, large screen scope that takes two 7000-series vertical plug-ins and one 7000-series horizontal plug-in. There is also a rack-mount version, the R7603.
The AN/USM 281C is a ruggedized 7603 without readout (was also known as 7603N Option 11S) that includes two AM-6565 (7A15AN11) single-trace amplifiers, a TD-1085 (7B53AN11) dual time base, and a clip-on front panel cover with probes and accessories.
|Bandwidth||100 MHz with 7A11, 7A16, 7A17, 7A24, 7A26; 110 MHz with 7A19, 70 MHz with 7A18|
|Fastest calibrated sweep||5 ns/Div|
|CRT std.||P31 phosphor, 8 × 10 divisions of 1.22 cm (Tek T7400/154-0640-00 tube); 15 kV acceleration (-3/+12); Option 8: P11 phosphor|
|CRT Opt. 4||P31 phosphor, 8 × 10 divisions of 1.0 cm (Tek 154-0672-00 tube); 18 kV acceleration|
|CRT Opt. 6||P31 phosphor, 8 × 10 divisions of 1.22 cm (Tek 154-0673-00 tube, spectrum analyzer graticule)|
|Vertical modes||Left / Alt / Add / Chop / Right|
|Trigger Source||Left / Vert Mode / Right|
|Outputs||Camera power, Vert signal, +Gate, +Sawtooth|
|Line Voltage||100 / 110 / 120 / 200 / 220 / 240 V, +/- 10%, 50—440 Hz|
|Power||Max. 170 W|
|Weight||13.6 kg / 30 lb (instrument only)|
|Operating Environment||0°C – +50°C, < 15,000 ft|
Due to the long production time of the 7603 many options were available. As some options became standard (e.g. built-in fan) some numbers where assigned twice. Later models were equipped with an IEC socket, making all Ax options obsolete.
- Opt.1: Without readout (= 7603N)
- Opt.3: Extra EMI shielding
- Opt.4/Opt.13: Maximum-brightness CRT with reduced area (8x10 cm graticule)
- Opt.5: Fan
- Opt.5 (later models): 400 Hz line frequency
- Opt.6: Spectrum analyzer graticule
- Opt.7: Without Signals Out
- Opt.8: P11 phosphor
- Opt.8 (later models): protective front panel cover, 7603 only
- Opt.11S: Ruggedized variant AN/USM 281C, specified at 50 MHz
- Opt.20: Rear GPIB socket for 7D20, removes +Sawtooth, +Gate, vertical signal outputs, R7603 only
- Opt.76: P7 phosphor
- Opt.77: P7 phosphor with spectrum analyzer graticule
- Opt.78: P11 phosphor
The 7603 was made in various versions for many years, with revisions to some subassemblies like the vertical output amplifier and HV circuits. It uses a linear power supply, a fan is optional. CRT deflection plates are not distributed. The vertical output amplifier is built around a 155-0080-00 hybrid (U450). Other custom Tek ICs used include 155-0011-00 clock & chop blanking (U55), 155-0022-00 vertical channel switch (U214), 155-0022-00 trigger channel switch (U324),and the 7000 series readout system chips.
Official Modification 36005 added a ground strap to the vertical amplifier to prevent >1 GHz oscillations.
There was an official Tek modification to add pushbutton illumination for plugins, which involves adding a regulator, but there is also a quick'n'dirty method from Rolynn Prechtl:
I've done multiple units the cheap and dirty way. No additional regulator, no pulling the LVPS to find a place to add extra components and the best part, no cost.
Look for P90 and P10 on the rear edge of the Main Interface ECB (left side as I remember).
Connect P10-1 (gnd) P90-7 or 8 (gnd).
Connect P10-2 (+5V) to P90-4 (+5V).
Two wires and you're done.
Have experienced no problems with the extra current demand from the +5V regulated supply.
|Mainframe only||Catalog price||$1,600||$1,800||$2,260||$2,865||$4,235|
|Mainframe with 2 × 7A18 + 7B53||Catalog price||$3,520||$3,955||$5,225||$6,880||$10,315|
- Detailed repair report @ amplifier.cd (German) / (translated)
- Tek 7603 @ barrytech.com
- Catalog page with specs
- Repair Report #2
- Repair Report #3
- Repair Report #4 - 7603 with 7D20
- EB5AGV's Tektronix R7603 / 7D20 page
- Picture of a completely disassembled 7603