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7904: Difference between revisions
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Added information about fast sweep issue for early models
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(Added information about fast sweep issue for early models) |
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==Internals== | ==Internals== | ||
The 7904 | The 7904(A) incorporates a 65 ns Y delay line. | ||
This delay is too short for some older time bases such as [[7B53]] to display the trigger event. | This delay is too short for some older time bases such as [[7B53]] to display the trigger event. The signal path is completely differential and the internal signal wiring is 50 Ω coax. | ||
The CRT ([[154-0644-05]]) has [[distributed vertical deflection plates]]. | |||
===7904=== | |||
The 7904 uses a switch-mode power supply and has no fan. | |||
[[Thor Hallen]] designed the main vertical amplifier and the [[7A19]] plugin (Note 1). | [[Thor Hallen]] designed the main vertical amplifier and the [[7A19]] plugin (Note 1). | ||
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The 7904 makes extensive use of custom integrated circuits and hybrid circuits, inter alia, the [[155-0064-00]] 470-ps output amplifier, | The 7904 makes extensive use of custom integrated circuits and hybrid circuits, inter alia, the [[155-0064-00]] 470-ps output amplifier, | ||
[[155-0022-00]] analog multiplexer for channel switching, [[155-0059-00]] HF amplifier, | [[155-0022-00]] analog multiplexer for channel switching, [[155-0059-00]] HF amplifier, | ||
[[155-0095-01]] and [[155-0095-03]] differential HF amplifiers, and [[155-0067-02]] SMPS controller. | [[155-0095-01]] and [[155-0095-03]] differential HF amplifiers, and [[155-0067-02]] SMPS controller. | ||
Early 7904 have issues with horizontal aberrations for sweep rates of 1 ns/Div or faster. After discovery of the issue modification kits that replace the horizontal amplifier were offered. For more information see the table below and the [[Media:Tek 067-0657-00 with schematics.pdf|manual]] of the [[067-0657-00|067-0657-00 Normalized Ramp Generator]] that was use to investigate this issue. | |||
{| class="wikitable" | |||
|- | |||
! Serial Number | |||
! Issue | |||
! Modification Kit | |||
|- | |||
|B010000-B081987 | |||
|Fully calibrated sweeps for rates of 1 ns/Div or faster requires a dedicated [[7B92]] (non A!) and the two units to be calibrated as a system. | |||
|050-0636-01 | |||
|- | |||
|B081988-B219999 | |||
|Can be calibrated to either work with magnifier timebases ([[7B70]],[[7B80]]), or alternatively non-magnifying time bases ([[7B92A]]), but not both. | |||
|040-0791-00 | |||
|- | |||
|B220000 and above | |||
|None - fully compatible with all timebases and all sweep rates. | |||
|− | |||
|} | |||
The | ===7904A=== | ||
The 7904A is a complete redesign and uses the [[155-0173-05]], [[155-0175-05]] and [[155-0178-05]] amplifiers developed for the [[7104]]. A fan is added at the rear switch mode power supply. | |||
==Prices== | ==Prices== | ||