549: Difference between revisions

549 (view source)

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 There is a remote control cable/switch,
 part number 012-0102-00 (photo below), that can erase the screen and reset the single sweep.
-===Low Voltage Power Supply===
-Low Voltage Power Supply provides voltage for all the stages and heater voltage. It provides DC -12.4V, -150V, +100V, +225V, +300V, +350V, +500 regulated output and +475V Unregulated output.
+===Power Supply===
+The 549's power supply provides regulated outputs of −12.4 V, −150 V, +100 V, +225 V, +300 V, +350 V, and +500 V as well as a +475 V unregulated output.
 Line input is connected to main transformer primary via two switches, one to select 110/230V Range - (which is inside the chassis) and another switch (on the rear of the chassis) to select Low/Medium/High voltage range in both the above line voltage class.
 Multiple secondary windings feeds diodes for rectification for different voltages. Both center-tap and bridge configuration is used.
-Transistors and/or Tubes are used for regulation.
+Transistors and/or tubes are used for regulation.
-The design regulates one power rail (of -150V in this case) and refer all other voltage rails to this output to keep all voltages stable.
-This enables adjusting all rail voltages with one Trim resistor/Potentiometer.
-VR Tube is used as the reference for -150V, 12AX7 is used as the Comparator, 3 Nos of 12B4 are used as series regulator tubes. 6AU6 is used as error amplifier.
-Most other stages replicate the same design, except slight changes in Tubes used,6080 Tube is used as series regulator for +350V, +225V and +100V
+As is common in many Tektronix scopes, all regulated voltages are referred to the negative regulated rail (−150 V in this case) by fixed low-tolerance dividers.  Only the −150 V voltage is trimmed, its reference is a [[5651]] VR tube.  A [[12AX7]] is used as the comparator, three [[12B4]] in parallel are used as series pass tubes. A [[6AU6]] is used as an error amplifier.
-The -12.4V rail is all transistor regulator.
+Most other stages replicate the same design, except slight changes in tubes used − the +350 V, +225 V and +100 V regulators employ a [[6080]] as the pass element.
-A thermal delay tube - Tek Part 148-0021-00 or 6N030 - which controls a relay is used to delay the plate voltages to the Tubes till they are warmed up. On power up, only heater voltage is applied to the tubes, which also drives the thermal delay tube. After a time delay of up to 60 seconds, the thermal delay tube activates the relay, powering all outputs ON. Unregulated +100V is used to drive this relay.
+The −12.4 V regulator is transistor-based.
-The circuit is designed such that Thermal delay tube cut itself off the circuit once it turns the relay and outputs on, but holding the relay on.
+The 549 power supply uses a [[delay relay|6N030 delay relay (P/N 148-0021-00)]] to control a relay that switches supply voltages on only after the tubes are warmed up. On power up, only heater voltage is applied to the tubes.  After a delay of up to 60 seconds, the thermal delay relay activates the main relay (driven from unregulated +100 V). This also cuts out the delay relay, which can cool down and will be ready to delay again even after a quick interrupt in power input.
-This allows the thermal delay tube to cool down and allow heater warmup time even after a quick interrupt in power input.
 ==Links==