7M13: Difference between revisions
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==Internals and Repair Issues== | ==Internals and Repair Issues== | ||
The 7M13 is relatively simple and robust electrically | The 7M13 is relatively simple and robust electrically, consisting mostly of 74xx TTL logic. | ||
However, there can be electromechanical problems due to the number of switches. | |||
For example, a 7M13 may appear unresponsive if the | For example, a 7M13 may appear unresponsive if the "(P)RESET" button for the camera counter is not fully released. | ||
The 7M13 uses four 7489 TTL 16×4 RAMs to store the characters entered, | The 7M13 uses four 7489 TTL 16×4 RAMs to store the characters entered, | ||
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One RAM and D/A each are assigned to row and column readout signals in each channel, | One RAM and D/A each are assigned to row and column readout signals in each channel, | ||
and are addressed by a counter synchronized to the readout time slot pulses. | and are addressed by a counter synchronized to the readout time slot pulses. | ||
In other words, characters are not stored | In other words, characters are not stored as ASCII bytes, but as row/column pairs | ||
matching the [[Media:Tek7000-readout-charset.jpg|readout system's character set]]. | matching the [[Media:Tek7000-readout-charset.jpg|readout system's character set]]. | ||
The keyboard is arranged in a matching matrix of double-contact (DPST) keys | The keyboard is arranged in a matching matrix of double-contact (DPST) keys | ||
Revision as of 13:10, 31 December 2022
The Tektronix 7M13 is a "Readout Unit" that allows the user to enter text into the scope's readout system for that module slot. It is intended to include identifying text and picture numbers for photographic documentation.
A built-in camera counter displays a pre-settable count in the second (lower) readout channel, which can be advanced manually by push-button or automatically by the camera shutter. The only editing function provided is to overwrite the character just entered (by holding the MODIFY button). To correct other errors, one needs to erase the display field.
Key Specifications
| Character positions | 2 fields (top, bottom) of 10 characters each |
|---|---|
| Camera counter | 0-99, lower field only; ground contact closure input |
Internals and Repair Issues
The 7M13 is relatively simple and robust electrically, consisting mostly of 74xx TTL logic. However, there can be electromechanical problems due to the number of switches. For example, a 7M13 may appear unresponsive if the "(P)RESET" button for the camera counter is not fully released.
The 7M13 uses four 7489 TTL 16×4 RAMs to store the characters entered, and four 155-0038-01 Tek-made D/A converter chips to drive the analog row/column readout lines. One RAM and D/A each are assigned to row and column readout signals in each channel, and are addressed by a counter synchronized to the readout time slot pulses. In other words, characters are not stored as ASCII bytes, but as row/column pairs matching the readout system's character set. The keyboard is arranged in a matching matrix of double-contact (DPST) keys that generate the row/column coordinates through 74147 priority encoders.
Links
Prices
| Year | 1974 | 1976 | 1980 | 1984 |
|---|---|---|---|---|
| Catalog price | $375 | $425 | $600 | $1,075 |
| In 2022 Dollars | $2,300 | $2,200 | $2,200 | $3,100 |
Pictures
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7M13 front panel
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7M13, right side
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7M13, left side
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Readout example (7844 Opt.78 mainframe)
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7M13 in 7633
Custom ICs used in the 7M13
| Page | Model | Part nos | Description | Designers | Used in |
|---|---|---|---|---|---|
| 155-0038-01 | 155-0038-01 | 155-0038-00 • 155-0038-01 | 5-bit current source D/A converter | Mike Metcalf | 7A42 • 7D13 • 7D14 • 7M13 • T4005 |