SG503: Difference between revisions

From TekWiki
Jump to navigation Jump to search
(Added service notes)
No edit summary
 
(18 intermediate revisions by 5 users not shown)
Line 1: Line 1:
{{TM500 | mfg=Tektronix | type=SG503 | function=250 MHz leveled sinewave generator | class=signal generator | image=sg503.jpg | introduced=1974 | discontinued=1993 |
{{TM500 | mfg=Tektronix | type=SG503 | function=250 MHz leveled sinewave generator | class=signal generator | image=SG503 Front Early.jpg | introduced=1974 | discontinued=1993 |
designers= |manuals=
designers= |manuals=
* [[Media:070-1622-01.pdf|Tektronix SG503 Manual]] (PDF, OCR)
* [[Media:070-1622-01-1974.pdf|SG503 Instruction Manual 070-1622-01 <br> Early type]]
* [[Media:070-1622-01.pdf|Tektronix SG503 Manual sn B010100 through B089999]]
* [[Media:070-1622-01.pdf|SG503 Manual 070-1622-01 <br> s/n: B010100 through B089999]]
* [[Media:070-6770-00.pdf|Tektronix SG503 Manual sn B090000 and up]]
* [[Media:070-6770-00.pdf|SG503 Manual 070-6770-00 <br> s/n: B090000 and up]]
* [[Media:Tek SG503 Wizard Workshop mods.pdf|SG503 Modifications from Wizards Workshop]]
}}
}}
It was primarily intended to be used as an oscilloscope calibration device for measuring bandwidths up to 250 MHz.  Unlike later instruments like the [[SG504]], it does not use a leveling head but was designed and calibrated with high quality coaxial cable (P/N 012-0482-00) to operate as a closely matched system when terminated into a 50 Ω load.
Nine overlapping ranges cover the frequency band from 250 kHz to 250 MHz, with an additional range reserved for a 50 kHz reference frequency.


Nine overlapping ranges cover the frequency band from 250 kHz to 250 MHz, with an additional range reserved for a 50 kHz reference frequency.
It was primarily intended to be used as an oscilloscope calibration device for measuring bandwidths up to 250 MHz.  Unlike later instruments like the [[SG504]], it does not use a leveling head but was designed and calibrated with high quality coaxial cable (P/N [[012-0482-00]]) to operate as a closely matched system when terminated into a 50 Ω load.


The SG503 shows the selected frequency on a 3-digit LED counter.
The SG503 shows the selected frequency on a 3-digit LED counter.
Line 13: Line 14:
{{BeginSpecs}}
{{BeginSpecs}}
{{Spec | Frequency | 50 kHz, 250 kHz to 250 MHz in nine ranges  }}
{{Spec | Frequency | 50 kHz, 250 kHz to 250 MHz in nine ranges  }}
{{Spec | Frequency accuracy |  Within ±0.7% of one count of the least significant displayed digit for the indicated frequency }}
{{Spec | Frequency accuracy |  Within ±0.7 of one count of the least significant displayed digit for the indicated frequency }}
{{Spec | Amplitude |  5 mV<sub>p-p</sub> to 5.5 V<sub>p-p</sub> in three decade ranges (terminated into a 50 Ω load)  }}
{{Spec | Amplitude |  5 mV<sub>p-p</sub> to 5.5 V<sub>p-p</sub> in three decade ranges (terminated into a 50 Ω load)  }}
{{Spec | Harmonics | 2<sup>nd</sup> harmonic ≥35 dB down from fundamental, 3<sup>rd</sup> and higher harmonics ≥40 dB down }}
{{Spec | Harmonics | 2<sup>nd</sup> harmonic ≥35 dB down from fundamental, 3<sup>rd</sup> and higher harmonics ≥40 dB down }}
Line 24: Line 25:
The SG503 uses two LC Hartley oscillators, one for 100 MHz and above with an air-core inductor, the other for the lower ranges using switched ferrite-core inductors.  Tuning is accomplished via a traditional three-section variable capacitor. After filtering, a regulated power amplifier stage (caution: [[beryllium oxide]] in transistor cases!) is followed by a peak-to-peak detector for the amplitude control loop, and switchable output attenuators.
The SG503 uses two LC Hartley oscillators, one for 100 MHz and above with an air-core inductor, the other for the lower ranges using switched ferrite-core inductors.  Tuning is accomplished via a traditional three-section variable capacitor. After filtering, a regulated power amplifier stage (caution: [[beryllium oxide]] in transistor cases!) is followed by a peak-to-peak detector for the amplitude control loop, and switchable output attenuators.


The frequency counter is built from a 10131 ECL prescaler followed by 7490 TTL BCD counters and 7-segment decoders (display not multiplexed).
The frequency counter circuit starts with a ÷8 prescaler (SP1670 and 10131 ECL flip-flops) followed by 7490 TTL BCD counters and 7-segment decoders (display not multiplexed).


==Notes==
==Notes==
The Tek 012-0482-00 cable is made from RG-223 50 Ω double-braid shielded coaxial cable (or equivalent), and is exactly 36" from end-to-end.
The Tek [[012-0482-00]] cable is made from RG-223 50 Ω double-braid shielded coaxial cable (or equivalent), and is exactly 36" from end-to-end.


==Service Notes==
==Links==
* Out of Range At About 1 MHz - Suspect U390 - Plessey brand biggest problems.
* [https://www.amplifier.cd/Test_Equipment/Tektronix/Tektronix_500/SG503.htm SG503 @ amplifier.cd] (German) including measurements of cable influence (1 m Belden H-155 as replacement for original cable)
* No Output and Flashing Display - Suspect Oscillator circuits.
* [[Media:SG503_P2P_Substitute_REVISED.pdf|SG503 Peak-to-Peak detector substitute]] by John K. Bennett AE0AM
* Display Does Not Vary With Output - Suspect Auto Ranging Circuits Q410 , CR410 , and 2420.
* [https://www.youtube.com/watch?v=oRUtsDIOA40 SG503 Lab Check In and Calibration] by Zenwizard Studios @ YouTube
* No Display Verify that 1432C - 10 is lo , a Hi will disable display.
* [https://www.youtube.com/watch?v=O0E6QeX82LY Tektronix SG503 Refresh and Alignments] by Zenwizard Studios @ YouTube
* No Display - Except In 50 kHz Position:
{{Documents|Link=SG503}}
**1 . Check for Reference Clock signal at U460D- 11.
**2 . If signal is okay suspect Auto Clock Enable circuits.
* 50 kHz Oscillator Has No Output - Suspect C134 has leakage.
* Certain Bands Are Defective - Suspect Band Selection switch , selected coil , or selected capacitor.
* One Band Flashes at Lo or High End of Band - Adjust core in selected coil , especially 25-50 MHz and 10-25 MHz ranges.
* Oscillator OK But No Output From Buffer Amplifier:
**1 . Suspect LR190 is open , if open you'll have -20 Volts on 0190 Collector.
**2 . If Q190 Collector is okay check for signal on cathode of CR225A. If signal is present suspect the Pk - Pk Detector is open or the attenuators are bad.
* To Determine If Your Oscillator Circuits Or Leveling Circuits are bad - Remove Q300 and connect one end of a 2K12 potentiometer to Q300's Emitter circuit and the wiper arm of the potentiometer to Q300's collector circuit. If the oscillator breaks into oscillations where varying the potentiometer, your leveling circuits are bad.
* Levelling Circuit Defective:
**1 . Check for +.7 Volts at 1280-2 and for @ 6 Volts at U280-6.
**2 . If +.7 Volts is not present check divider string R255 through R265.
*+5 Volt Supply Bad:
**1. Lift F620 and see if +5 Volts now reads @ +11.2 Volts
***A. If +11.2 Volts is present your problem is external to supply.
***B. If +11.2 Volts is absent your supply is bad.
**2. If 0600 or 2620 is defective change both.
*Readout Miscounts At Higher Frequencies - Suspect U390 , 0350 , or 1400 devices or sockets.
* Levelling Problems - Suspect U225 and 2190.
* Sinewave Flattens At Higher Frequencies - Suspect Q190 , CR200 , CR202 , VR200 , and VR202.
* Levelling Or Loading Problem On One Range Only - Suspect selected coil on coil circuit board.
* No Output On A Number Of Ranges - Suspect plates of C100 are shorting together.
* Sinewave Distorted, has Spikes or Ringing - Suspect Q160 is open.
*Distorted Waveform At 50 MHz And Above - Suspect C204 , C208 , and C212.
* Clipped Waveforms (Positive, Negative , or Both ) - Suspect CR200 , CR202 , VR200 , and VR202.
* Peak to Peak Detector (U255 ) Checkout - Using a DM501 on the 200 ohm range you should have 50 Ω in both directions across the signal path pins. When checking across the control pins you should have 50 Ω in one direction and in the reverse position.
* Levelling Problems Across More Than One Range - Suspect U225
* Amplitude potentiometer Has No Effect:
**1. Suspect U225 is cracked , when using ohm meter it may check good.
**2. Suspect CR216 and / or CR218 is open.
**3. Suspect open cable between P230 and P265.
**4. Suspect U280 or 0300 is open.
*No Output:
**1. Suspect L200 is shorting to shield.
**2. Suspect 4.5 Volt supply is shorted to ground which will cause 1630 to overheat.
* 50 kHz to 100 MHz Lo Band Oscillator , All Bands Not Operating properly - Suspect LR135 is broken , not the coil by the resistor.
* Display Is Blank Except Left Hand Decimal Point - Suspect Clock Oscillator and associated Dividers plus Enabling Gates.
* Display Miscounts When Unit Is Hot:
**1 . Suspect Pre- scaler I.C.'s , U390 or 0400 , if over 1 MHz.
**2. Suspect 7490 I.C.'s if below 1 MHz.
*The Display Has One or More Digits Reading Zero With No Change In Frequency While Remaining Digits May Be Free-Running - Suspect 1430, 4432, 0435, 1436, or U437.
*No Display - Suspect Q290 , Q296 , or R475 is open.
*Display Is All Zeros With No Variations - Suspect L660 is open.
*Display Has One Or More Digits Blanked, But Not All, and Remaining Digits Normal - Suspect 1510, 1520, and 1530.
*Binding Range Switch - Coil circuit board or wafer switch on coil circuit board needs replacement.
*Display at @130 - 160 MHz, Goes To A11 Zeros And Stays There - Suspect 1390 or 1400, maybe heat sensitive.
*Unit Normal Except In Reference Positions Where Display Free Runs - Suspect defective cable between P280 and P290.
*Replacing L110 - If L110 requires replacement the old tuning slug should be used in the new coil. Otherwise, you may not be able to adjust the new coil to meet distortion and/ or levelling in the 25 to 50 MHz Band.
*Normal Tuning Slug Positions In Coils:
**L116 Slug set to bottom resonance
**L114 Slug set to top resonance
**L112 Slug set to bottom
**L110 Slug set to top
**L100 Slug set to top


==Links==
==Prices==
* [http://www.amplifier.cd/Test_Equipment/Tektronix/Tektronix_500/SG503.htm SG503 @ amplifier.cd] (German) including measurements of cable influence (1 m Belden H-155 as replacement for original cable)
{| class="wikitable sortable"
* [https://www.youtube.com/watch?v=oRUtsDIOA40 Zenwizard Studios - SG503 Lab Check In and Calibration]
|-
! Year
! 1979
! 1980
|-
! Catalog Price
| align="right" | $1,325
| align="right" | $1,375
|-
! In 2023 Dollars
| align="right" | $5,600
| align="right" | $5,100
|}
 
According to an [[Media:Tek Schottky Diodes Memo rot.pdf|internal memo]], annual sales were estimated at 1200 units in 1979.


==Pictures==
==Pictures==
'''Early model'''
<gallery>
Tek SG503 early front.jpg              |
SG503_Front_Early.jpg                  |
Tek SG503 early left.jpg                | Left Internal
Tek SG503 early right.jpg              | Right Internal
Tek SG503 Attenuator Board.jpg          | Attenuator Board Part
Tek SG503 Attenuator Board Top.jpg      | Attenuator Board Top
Early SG503 Attenuator Board Bottom.jpg | Attenuator Board Bottom
</gallery>
'''Late model'''
<gallery>
<gallery>
Sg503.jpg | Early SG503
SG503_Front_Late.jpg
Tek sg503 late.jpg | Late SG503
Tek sg503 late.jpg
SG503_Left_Late.jpg                    | Left Internal
SG503_Right_Late.jpg                    | Right Internal
Tek sg503 left internal.jpg
Tek sg503 left internal.jpg
Tek sg503 rear internal.jpg
Tek sg503 rear internal.jpg
Line 103: Line 79:
</gallery>
</gallery>


{{Custom ICs|SG503}}
==Components==
{{Parts|SG503}}

Latest revision as of 15:56, 4 December 2023

Tektronix SG503
250 MHz leveled sinewave generator
Tektronix SG503

Produced from 1974 to 1993

Manuals
Manuals – Specifications – Links – Pictures

The Tektronix SG503 is a 250 MHz leveled sinewave generator plug-in for the TM500 system.

Nine overlapping ranges cover the frequency band from 250 kHz to 250 MHz, with an additional range reserved for a 50 kHz reference frequency.

It was primarily intended to be used as an oscilloscope calibration device for measuring bandwidths up to 250 MHz. Unlike later instruments like the SG504, it does not use a leveling head but was designed and calibrated with high quality coaxial cable (P/N 012-0482-00) to operate as a closely matched system when terminated into a 50 Ω load.

The SG503 shows the selected frequency on a 3-digit LED counter.

Key Specifications

Frequency 50 kHz, 250 kHz to 250 MHz in nine ranges
Frequency accuracy Within ±0.7 of one count of the least significant displayed digit for the indicated frequency
Amplitude 5 mVp-p to 5.5 Vp-p in three decade ranges (terminated into a 50 Ω load)
Harmonics 2nd harmonic ≥35 dB down from fundamental, 3rd and higher harmonics ≥40 dB down

Rear interface

The sine output, remote amplitude control input, and a 12-bit non-multiplexed BCD version of the counter value are available via the rear connector.

Internals

The SG503 uses two LC Hartley oscillators, one for 100 MHz and above with an air-core inductor, the other for the lower ranges using switched ferrite-core inductors. Tuning is accomplished via a traditional three-section variable capacitor. After filtering, a regulated power amplifier stage (caution: beryllium oxide in transistor cases!) is followed by a peak-to-peak detector for the amplitude control loop, and switchable output attenuators.

The frequency counter circuit starts with a ÷8 prescaler (SP1670 and 10131 ECL flip-flops) followed by 7490 TTL BCD counters and 7-segment decoders (display not multiplexed).

Notes

The Tek 012-0482-00 cable is made from RG-223 50 Ω double-braid shielded coaxial cable (or equivalent), and is exactly 36" from end-to-end.

Links

Documents Referencing SG503

Document Class Title Authors Year Links
070-2088-00.pdf Book TM500 Series Rear Interface Data Book 1975 AF501 • AM501 • AM502 • DC501 • DC502 • DC503 • DC504 • DC505 • DC505A • DM501 • DM502 • FG501 • FG502 • FG503 • MR501 • PG501 • PG502 • PG505 • PG506 • PG508 • PS501 • PS502 • PS503 • PS503A • PS505 • RG501 • SC501 • SC502 • SG502 • SG503 • TG501
070-2088-01.pdf Book TM500 Series Rear Interface Data Book 1976 AF501 • AM501 • AM502 • AM511 • DC501 • DC502 • DC503 • DC504 • DC505 • DC505A • DD501 • DM501 • DM502 • FG501 • FG502 • FG503 • FG504 • LA501 • MR501 • PG501 • PG502 • PG505 • PG506 • PG508 • PS501 • PS502 • PS503 • PS503A • PS505 • RG501 • SC501 • SC502 • SG502 • SG503 • SG504 • SW503 • TG501 • TR501 • TR502

Prices

Year 1979 1980
Catalog Price $1,325 $1,375
In 2023 Dollars $5,600 $5,100

According to an internal memo, annual sales were estimated at 1200 units in 1979.

Pictures

Early model

  • Left Internal

    Left Internal

  • Right Internal

    Right Internal

  • Attenuator Board Part

    Attenuator Board Part

  • Attenuator Board Top

    Attenuator Board Top

  • Attenuator Board Bottom

    Attenuator Board Bottom

Late model

  • Left Internal

    Left Internal

  • Right Internal

    Right Internal

Components

Some Parts Used in the SG503

Part Part Number(s) Class Description Used in
151-0614-00 151-0614-00 Discrete component Tek-made RF power transistor SG503
155-0107-00 155-0107-00 Hybrid integrated circuit leveller SG503
Retrieved from "https://w140.com/tekwiki/index.php?title=SG503&oldid=89075"