DM502: Difference between revisions

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{{TM500 | mfg=Tektronix | type=DM502 | function=basic 3½ digit digital multimeter | class=multimeter | image=Tek dm502 e1.jpg | introduced=1975 | discontinued=1988 |
{{TM500 | mfg=Tektronix | type=DM502 | function=basic 3½ digit digital multimeter | class=multimeter | image=Tek dm502 front.jpg | introduced=1975 | discontinued=1980|
manuals=
designers= |manuals=
* [http://w140.com/tek_dm502.pdf Tektronix DM502 Manual (PDF)]
* [[Media:070-1726-00.pdf|Tektronix DM502 Manual]]
* [http://w140.com/smb/DM502A_SM.pdf Tektronix DM502A Manual (OCR, PDF)]
* [[Media:Tek DM502 mods.pdf|Tektronix DM502 Modification Summary]]
}}
}}
It was [[introduced in 1975]] and superseded by the [[DM502A]] in 1980.
It has an Int/Ext switch that allows alternate input connections via the rear interface to be selected.
It has an Int/Ext switch that allows alternate input connections via the rear interface to be selected.


The DM502A model adds an input for a PT-100 temperature probe ([[P6601]]), a true RMS converter, and offset circuits to read dB directly in all ranges.
The DM502 is available with an input for temperature measurement with a transistor temperature probe ([[P6430]]) using an NPN transistor, e.g. a 2N2484 (any NPN-Transistor with h<sub>FE</sub> >150 can be used).


{{BeginSpecs}}
{{BeginSpecs}}
{{Spec | Voltage ranges | 200 mV to 200 V in decade steps; 1 kV (DC) / 500 V (AC) top range}}
{{Spec | Voltage ranges | 200 mV to 200 V in decade steps; 1 kV (DC) / 500 V (AC) top range}}
{{Spec | Input impedance DM502A | 10 MΩ}}
{{Spec | Current ranges | 200 μA to 2 A in decade steps }}
{{Spec | Current ranges | 200 μA to 2 A in decade steps }}
{{Spec | Resistance ranges | 200 Ω to 20 MΩ in decade steps }}
{{Spec | Resistance ranges | 200 Ω to 20 MΩ in decade steps }}
{{EndSpecs}}
{{EndSpecs}}
An "Option 2" instrument deletes the temperature measurement function,
==Links==
* [https://www.youtube.com/watch?v=Tx6DtLooCOs Tektronix DM502 Multimeter Repair] by NFM @ YouTube
* [https://www.youtube.com/watch?v=AfQkfZfGKkw Tektronix DM 502A Restoration and Calibration for a Viewer] @ Zenwizard Studios YouTube
{{Documents|Link=DM502}}
{{PatentLinks|DM502}}
==Internals==
The DM502 circuit is built around a Siliconix LD110/111 DMM chipset. 
The entire unit with exception of the temperature circuit can be elevated up to 1 kV above chassis ground. 
For this purpose, it is supplied through a mains-frequency isolation transformer with a 50 V primary that is supplied from the two 25 V<sub>AC</sub> windings in the mainframe connected in series.
This transformer feeds a a discrete +5 V regulator, and an RC4194D regulator for +/–12 V. 
The rear interface supports a digit-serial BCD output but the manual cautions that ''only the Temp Out, Temp GND and HI and LO inputs are factory-wired'', the BCD connections must be soldered in by the user if needed – presumably because the digital section is not galvanically separated from the floating input ground. In Temperature mode, the floating ground is connected to the chassis ground (because the temperature circuit uses the mainframe's ±33 V supplies) but the V/A inputs are disconnected.


==Pictures==
==Pictures==
===DM502===
<gallery>
<gallery>
Tek dm502 e1.jpg
Tek dm502 front.jpg
Tek dm502 front.jpg
Tek dm502 e1.jpg      | DM502 Opt.2 (no temperature function)
Tek dm502 left.jpg
Tek dm502 left.jpg
DM502_switch_inside.jpg|DM502 switch with cover off.  The cover removes easily using a Pozidriv screwdriver.
Tek dm502 right.jpg
Tek dm502 right.jpg
Tek dm502 leftfront.jpg
Tek dm502 leftfront.jpg
Line 26: Line 45:
Tek dm502 rightfront.jpg
Tek dm502 rightfront.jpg
Tek dm502 rightrear.jpg
Tek dm502 rightrear.jpg
DM502_rear_con.JPG|DM502 Rear connector
DM502_rear_con.JPG | DM502 rear interface – see note above
</gallery>
</gallery>


===DM502A===
==Components==
<gallery>
{{Parts|DM502}}
Tek-dm502a-f.jpg
Tek dm502a 1.jpg
Tek dm502a 2.jpg
Tek dm502a right internal.jpg|DM502A right internal
</gallery>
 
 
[[Category:Specifications needed]]


[[Category:TM500 multimeter plugins]]
[[Category:TM500 multimeter plugins]]
[[Category:Introduced in 1975]]
[[Category:Introduced in 1975]]

Latest revision as of 05:22, 6 October 2024

Tektronix DM502
basic 3½ digit digital multimeter
Tektronix DM502

Produced from 1975 to 1980

Manuals
(All manuals in PDF format unless noted otherwise)
Manuals – Specifications – Links – Pictures

The Tektronix DM502 is a basic 3½ digit digital multimeter plug-in for the TM500 system.

It was introduced in 1975 and superseded by the DM502A in 1980.

It has an Int/Ext switch that allows alternate input connections via the rear interface to be selected.

The DM502 is available with an input for temperature measurement with a transistor temperature probe (P6430) using an NPN transistor, e.g. a 2N2484 (any NPN-Transistor with hFE >150 can be used).

Key Specifications

Voltage ranges 200 mV to 200 V in decade steps; 1 kV (DC) / 500 V (AC) top range
Input impedance DM502A 10 MΩ
Current ranges 200 μA to 2 A in decade steps
Resistance ranges 200 Ω to 20 MΩ in decade steps

An "Option 2" instrument deletes the temperature measurement function,

Links

Documents Referencing DM502

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
070-2088-04.pdf Book TM500 Series Rear Interface Data Book 1985 AA501 • AF501 • AM501 • AM502 • AM503 • AM511 • DC501 • DC502 • DC503 • DC503A • DC504 • DC505 • DC505A • DC508 • DC508A • DC509 • DC510 • DC5009 • DC5010 • DD501 • DL502 • DM501 • DM501A • DM502 • DM502A • DM505 • DM5010 • FG501 • FG501A • FG502 • FG503 • FG504 • FG507 • FG5010 • LA501 • LA501W • WR501 • MR501 • PG501 • PG502 • PG505 • PG506 • PG507 • PG508 • PS501 • PS502 • PS503 • PS503A • PS505 • PS5010 • RG501 • SC501 • SC502 • SC503 • SC504 • SG502 • SG503 • SG504 • SG505 • SW503 • TG501 • TR501 • TR502 • MI5010 • MX5010 • SI5010

Patents that may apply to DM502

Page Title Inventors Filing date Grant date Links
Patent US 3562464A Cam actuated switch having movable and fixed contacts on circuit board Howard Vollum • Willem H Verhoef • Tony Sprando 1968-10-07 1971-02-09 Cam switches • 2101 • 2701 • 2703 • 432 • 434 • 465 • 475 • 5A15N • 5A18N • 5A20N • 5A21N • 5A38 • 5A45 • 5B10N • 5B12N • 7A15 • 7A16A • 7A18 • 7A19 • 7A24 • 7A26 • 7B10 • 7B15 • 7B50 • 7B51 • 7B52 • 7B53A • 7B50A • 7B70 • 7B71 • 7B80 • 7B85 • 7B87 • 7B92 • 7B92A • 7D01 • 7D12 • 7D15 • 7J20 • 7S12 • 7T11 • 7T11A • AF501 • AM502 • AM503 • DC502 • DC503 • DC504 • DC505 • DM501 • DM502 • FG501 • FG501A • FG502 • FG503 • FG504 • FG507 • PG501 • PG502 • PG505 • PG506 • PG506A • PG508 • TG501 • SC502 • SC503 • SC504

Internals

The DM502 circuit is built around a Siliconix LD110/111 DMM chipset.

The entire unit with exception of the temperature circuit can be elevated up to 1 kV above chassis ground. For this purpose, it is supplied through a mains-frequency isolation transformer with a 50 V primary that is supplied from the two 25 VAC windings in the mainframe connected in series. This transformer feeds a a discrete +5 V regulator, and an RC4194D regulator for +/–12 V.

The rear interface supports a digit-serial BCD output but the manual cautions that only the Temp Out, Temp GND and HI and LO inputs are factory-wired, the BCD connections must be soldered in by the user if needed – presumably because the digital section is not galvanically separated from the floating input ground. In Temperature mode, the floating ground is connected to the chassis ground (because the temperature circuit uses the mainframe's ±33 V supplies) but the V/A inputs are disconnected.

Pictures

  • DM502 Opt.2 (no temperature function)

    DM502 Opt.2 (no temperature function)

  • DM502 switch with cover off. The cover removes easily using a Pozidriv screwdriver.

    DM502 switch with cover off. The cover removes easily using a Pozidriv screwdriver.

  • DM502 rear interface – see note above

    DM502 rear interface – see note above

Components

Some Parts Used in the DM502

Part Part Number(s) Class Description Used in
CA3046 156-0048-00 Monolithic integrated circuit transistor array 4601 • 7104 • 7403N • 7503 • 7B53A • 7D12 • DM502 • FG504 • S-52 • Telequipment D34 • 7603 • 7613 • 7623 • 7633 • FG507 • Keithley 227
Siliconix LD110/111A 156-0476-00 • 156-0476-00 • 156-1268-00 Monolithic integrated circuit 3½ digit A/D converter DM502 • DM502A • DM505
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