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* [http://w140.com/smb/7m13_sm.pdf Tektronix 7M13 Manual (OCR, PDF)]}} | * [http://w140.com/smb/7m13_sm.pdf Tektronix 7M13 Manual (OCR, PDF)]}} | ||
The '''Tektronix 7M13''' is a "Readout Unit" that allows the user to enter text into the [[7000 series readout system|scope's readout system]] for that module slot. | The '''Tektronix 7M13''' is a "Readout Unit" that allows the user to enter text | ||
into the [[7000 series readout system|scope's readout system]] for that module slot. | |||
It is intended to include identifying text and picture numbers for photographic documentation. | 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 through the a camera shutter. | 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 through the a 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. | |||
{{BeginSpecs}} | {{BeginSpecs}} | ||
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==Internals and Repair Issues== | ==Internals and Repair Issues== | ||
The 7M13 is relatively simple and robust electrically (consisting mostly of 74xx TTL logic), however, due to the number of switches, there can be electromechanical problems. | The 7M13 is relatively simple and robust electrically (consisting mostly of 74xx TTL logic), | ||
however, due to the number of switches, there can be electromechanical problems. | |||
For example, a 7M13 may appear unresponsive if the camera counter "(P)RESET" button 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. | 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 in ASCII bytes but in row/column pairs | |||
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 | |||
that generate the row/column coordinates through 74147 priority encoders. | |||
==Links== | ==Links== |