DM504A: Difference between revisions
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* [[Media:070-6945-00.pdf| | * [[Media:070-6945-00.pdf|DM504A Operator Manual 070-6945-00]] | ||
* [[Media:070-7135-00.pdf|DM504A Service Manual 070-7135-00]] | |||
{{ROM Images}} | {{ROM Images}} | ||
* [[Media:160-5426-05.bin|160-5426-05]] / [[Media:160-5426-00.bin|160-5426-00]] (27C64) ''please add'' | * [[Media:160-5426-05.bin|160-5426-05]] / [[Media:160-5426-00.bin|160-5426-00]] (27C64) ''please add'' | ||
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==Links== | ==Links== | ||
* [http://www.barrytech.com/tektronix/tektm500/tekdm504a.html DM504A @ barrytech.com] | * [http://www.barrytech.com/tektronix/tektm500/tekdm504a.html DM504A @ barrytech.com] | ||
* [https:// | * [https://youtube.com/watch?v=b-xhF_-hiqM DM504A repair] by VintageTEK Museum @ YouTube | ||
{{Documents|Link=DM504A}} | {{Documents|Link=DM504A}} | ||
Revision as of 06:15, 2 December 2023
The Tektronix DM504A is an 4½ digit autoranging digital multimeter plug-in for the TM500 system.
Key Specifications
| DC Voltage | 200 mV to 1000 V in decade steps, ±0.05%; Input resistance 10 MΩ (200 kΩ in 0.2 and 2 V ranges if Vin > 12 V) |
|---|---|
| AC Voltage | 200 mV to 500 V in decade steps, ±0.6%; Input resistance 10 MΩ // 100 pF |
| DC current | 200 μA to 2 A in decade steps, ±0.1%; |
| AC current | 200 μA to 2 A in decade steps, ±0.6%; |
| Resistance | 200 Ω to 20 MΩ in decade steps, 0.05% (0.1% in 2 and 20 MΩ ranges |
| Temperature | −62 °C to +230°C with P6602 2-wire PT-100 probe |
| Display | 4½ digits, red LED, 2/s update rate |
| Features |
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Links
- DM504A @ barrytech.com
- DM504A repair by VintageTEK Museum @ YouTube
Documents Referencing DM504A
- (no results)
Internals
The DM504A has no rear interface I/O. The entire circuit is supplied from a +12/−12/+5 V floating power supply that uses a small mains-frequency transformer fed by one of the mainframe's 25 VAC windings.
The circuit is based on an 80C31 microcontroller with a Texas Instruments TL500C integrating A/D front-end and a 1N827 temperature-compensated zener reference. The DM504A is software-calibrated, storing cal constants in a 93C46 EEPROM. Calibration is triggered by pressing Up and Down buttons simultaneously while the internal cal jumper is in the "enabled" position.
Pictures
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DM504A
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DM504A
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DM504A LH Interior with HV shield in place
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DM504A RH Interior with HV shield in place
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DM504A LH Interior with HV shield removed
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DM504A RH Interior with HV shield removed
Components
Some Parts Used in the DM504A
| Part | Part Number(s) | Class | Description | Used in |
|---|---|---|---|---|
| AD737 | 156-3506-00 | Monolithic integrated circuit | RMS/DC converter | DM504A |
| Intel 8031 | Monolithic integrated circuit | 8-bit microcontroller | 11A33 • 571 • DM504A • DM511 • DM5110 |