Difference between revisions of "502"
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==Internals== | ==Internals== | ||
| − | + | The −150 V supply uses a [[5651]] voltage reference tube as its reference. | |
| + | |||
| + | The 6.2 V<sub>DC</sub> heater supply for the tubes in the first stage differential amplifier is transistor-regulated. | ||
This heater supply uses the −150 V supply as its reference. | This heater supply uses the −150 V supply as its reference. | ||
| − | |||
| − | |||
| − | |||
| − | + | There is no post-deflection acceleration. The CRT cathode voltage is −2.9 kV. | |
| − | |||
The early 502 uses a single supply for the upper beam and lower beam CRT cathodes (HV transformer [[120-114]]). | The early 502 uses a single supply for the upper beam and lower beam CRT cathodes (HV transformer [[120-114]]). | ||
| Line 73: | Line 71: | ||
This improvement allows slight differences in horizontal CRT sensitivity between | This improvement allows slight differences in horizontal CRT sensitivity between | ||
the two beams to be cancelled out in step 8 of the calibration procedure. | the two beams to be cancelled out in step 8 of the calibration procedure. | ||
| + | |||
| + | Later 502A models have a solid state (plus [[nuvistor]]) input stage, | ||
| + | a [[6DJ8]] as the deflection amplifier, and transistors as amplifiers and emitter followers (only in the newest version). | ||
The 502 has a 123 °F (50.5 °C) [[thermal cutoff]] switch. | The 502 has a 123 °F (50.5 °C) [[thermal cutoff]] switch. | ||
Revision as of 04:18, 22 December 2019
The Tektronix 502 is a dual-beam oscilloscope introduced in 1958, followed by the 502A in 1963. There is also a rack-mount model, the RM502A.
Both beams have differential inputs. The horizontal deflection plates are common to both beams.
Mod 104 on a 502 provides single sweep lockout. This feature is standard on the 502A, which also has beam finder switches for each channel.
A recessed switch in the left side panel allows the upper beam amplifier to be connected to the horizontal deflection plates for single-beam X-Y operation, providing a differential X input with the same sensitivity as the Y channel. The upper beam is positioned off screen in this mode.
If the combination of time base setting and magnification selector results in a sweep faster than 1 μs/div, the horizontal scale is not calibrated, and a lamp on the front panel lights up to remind the operator of that.
Specifications
| Deflection | 100 μV/cm to 20 V/cm, 1−2−5, ±3% |
|---|---|
| Bandwidth | 1 MHz @ 200 mV/cm and above; 400 kHz @ 50 mV/cm, 200 kHz @ 5 mV/cm, 100 kHz @ 200 μV/cm |
| CMRR | 502A: 40,000:1 @ 100 mV/cm and 1 kHz |
| Input impedance | 1 MΩ // 47 pF |
| Sweep | 1 μs/cm to 5 s/cm, 1−2−5, ±3%; magnifier ×2, ×5, ×10 or ×20 |
| CRT | Early 502: Type T60P2/T502P2/T5020P2; Late 502, 502A: Type T5021P2; (P1, P7 or P11 were available as options) 10 vertical and 10 horizontal 1 cm divisions 3 kV acceleration |
| Dimensions | 597 mm (23½") × 286 mm (11¼") × 381 mm (15") L×W×H |
| Weight | 23.6 kg (52lb) |
Prices
| Year | 1959 | 1961 | 1963 (A) | 1971 (A) |
|---|---|---|---|---|
| Catalog price | $825 | $825 | $1,050 | $1,265 |
| 2018 value | $7,070 | $6,890 | $8,560 | $7,790 |
Internals
The −150 V supply uses a 5651 voltage reference tube as its reference.
The 6.2 VDC heater supply for the tubes in the first stage differential amplifier is transistor-regulated. This heater supply uses the −150 V supply as its reference.
There is no post-deflection acceleration. The CRT cathode voltage is −2.9 kV.
The early 502 uses a single supply for the upper beam and lower beam CRT cathodes (HV transformer 120-114). Later models (1959+, see 070-090) and the 502A have separate supplies for the two CRT cathodes (HV transformer 120-150). This improvement allows slight differences in horizontal CRT sensitivity between the two beams to be cancelled out in step 8 of the calibration procedure.
Later 502A models have a solid state (plus nuvistor) input stage, a 6DJ8 as the deflection amplifier, and transistors as amplifiers and emitter followers (only in the newest version).
The 502 has a 123 °F (50.5 °C) thermal cutoff switch.
Links
- Tektronix 502A @ amplifier.cd (many internal pictures)
Pictures
502
502 with (single-beam) X-Y display
502 Mod.104 (single sweep), front
502 Mod.104 (single sweep), front from lower left
502 left interior
502 right interior
rubber shock mount of amplifier sub-chassis
502 bottom
502 trace
502 trace
502 front panel without knobs
502 power supply section in operation
502A
502A
502A right internal
502A right
502A left
502A rear
Solid-state input stage with two 6DJ*
502A vertical amp sn 25,997 to 30,999
RM502A
RM502A
RM502A rear
RM 502A
RM 502A display
RM 502A bottom
RM 502A transformer wiring
RM 502A top
RM 502A vibration-isolated vertical amp
Third version 502A, serial number ≥31,000
top side lower beam input amp and attenuator, bottom side of upper beam vert input board
late model RM502A
late model RM502A
late model RM502A
late model RM502A
late model RM502A
late model RM502A
late model RM502A
