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 university UC3
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 Return to top of page · Post #: 1 · Written at 14:54:56 on 21 July 2010.
Dmxtothemax's avatar
 Dmxtothemax
 Location: Cairns, QLD
 Member since 16 July 2010
 Member #: 699
 Postcount: 11

Does any one know where I could get a circuit for a university ociloscope, model no UC 3.
Its all valve and has a problem with the focus or screen supplies,
Its a nice old unit, otherwise seems ok.
 
 Return to top of page · Post #: 2 · Written at 16:52:41 on 21 July 2010.
Marcc's avatar
 Marcc
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5254

While you await: Same rules as a radio apply; If its got old electrolytic & paper caps it's likely to be a refit.

The Heathkit OS1 that I have had to be rebuilt as even the resistors had failed. Several Radio's & things around 1956 that I have serviced have been the same? I had an Astor RK recently & even the Mica's had let go... that's extremely rare.

Do check if the thing has a Selenium EHT "stick rectifier" on the CRT. They are notorious for self destructing, or going high in resistance.

I replaced the Heatkit one with a TV diode and that required 15K of series resistance to bring EHT to the nominal 730 VDC

Marc
 
 Return to top of page · Post #: 3 · Written at 11:44:32 on 27 July 2010.
Dmxtothemax's avatar
 Dmxtothemax
 Location: Cairns, QLD
 Member since 16 July 2010
 Member #: 699
 Postcount: 11

No selenium rectifier,
the screen supply appears to use a voltage multiplier,
and the focus uses an valve for rectification.
I dont think you can measure these voltages directly,
I think you need a high voltage probe, as the digital
multimeter loads it down.
This is why I am chasing the circuits.
 
 Return to top of page · Post #: 4 · Written at 11:27:17 AM on 8 August 2011.
Wa2ise's avatar
 Wa2ise
 Location: Oradell, US
 Member since 2 April 2010
 Member #: 643
 Postcount: 830

I realise that this is not timely, but there's a few schematics over at http://www.kevinchant.com/university.html.

I don't see your particular model of oscilliscope, but I do see another scope there. Maybe similar enough?


 
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