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Need circuit of Power Supply 110v Tektronix 475A Option 4

Global111

Nov 28, 2018
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I'm trying to restore the oscilloscope Tektronix 475A Option 4
I found on the Internet a good documention for the oscilloscope 475
However, my instance is different (Option 4)
I found documentation on the opton 4 circuit but it is of low quality
Can you send me a picture of a 110 volt channel circuit ?
My instance has Q1497 transistor (protection of Q1496 current)
 

Global111

Nov 28, 2018
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Nov 28, 2018
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I'm interested in the document:
tektronix 475 option 4 maintenance manual
 

73's de Edd

Aug 21, 2015
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Sir Global 111 . . . . .


O.K. you can forget worrying about the Option 4 design aspect of that unit, as I am certain that you are not going to be one of the very-very-very select few (x the power of 100) that would be be needing the additional RFI and EMI suppression of that unit unless being in a RFI EMI anechoic chamber / screen room and, even then, be using its DC powering option.
So this Option 4 unit is giving you MORE radiation suppression than the common version does.

As far as the units + 105V supply , it is tied / interlocked into some adjunct supplies being active also as I have marked it up on the schematic..

TEK RELEVANT SCHEMATIC:
peBFl4w.png


73's de Edd
. . . . . . . . . . .



I don't care HOW nice and fragrant the soap in their hand dispenser smells . . . . . you should never, never walk out of the rest room sniffing your fingers.
 

Global111

Nov 28, 2018
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Hm maybe I was wrong about Option 4 (Maybe other option ).... I need circuit wit current protection on Q1497
 

73's de Edd

Aug 21, 2015
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Sir Global 111. . . . . .

NEW SUPPLEMENTAL SCHEMATIC . . . .

On the supplies specified schematic just below, note that the Q1496 is being the primary
series regulating pass transistor, with a Q1497 being a current sensing transistor in its base circuitry and the Q1494 and Q1490 being go-no go sensing of the 50 V supply presence.

PROBLEMS. . . .

If you have problems with Q1496, it could try to not regulate and pass the full +136 supply voltage thru to the +110 supply . . .or . . . . a crunched C-E junction on the Q1497 could do the same thing.
With Q1494 and Q1490, being so highly resistively isolated, they are being more bullet proof.

THEN . . . . .

Find the schematic page with with CRT support circuitry on it and observe the top left corner, where the +110V supply feeds in, and then the immediate Q13XX + CR13XX series related parts that it feeds for Z axis circuitry.
See if any bad parts there are responsible for a shorting or excess current pull of your +110V supplies power input feed.
Its 4 different supply routes being fed, are being shown on the schema snippet.

Also, poor bypassing being provided by a main E- filter(s) could also be at fault, at the +50 and +105/+160 source of their raw DC filtering . . . . .C1412 - C1414 - C1428.

(Maybe other option )

The other option is being a " 7", which enables its electronic inverter to be powered up from a 24VDC power input source



Here 'ya go . . . now all at no extra charge to you . . . as

upload_2018-11-30_1-15-49.png


73"s de Edd
. . . . . . . . . .


I accidentally swallowed a whole ice cube yesterday and haven't pooped it out yet . . . . now I'm getting really-really scared, you guys.

 
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