Re: Tek 2753P Manuals

John Miles

There's not much upside in using the old Variac and/or light-bulb trick to
bring up a switching power supply. The switcher won't generally fail in a
way that draws excess AC line current. If a secondary rail is shorted, it
will simply refuse to start. Meanwhile, the combination of a shorted
secondary rail and an unusual high-impedance or low-voltage AC power
connection may not have been well-characterized by the original designer.
The best strategy is to just plug it in and hit the power switch.

-- john, KE5FX

Author/maintainer of the 49x service document, FWIW :)

From: []
Sent: Thursday, December 14, 2017 5:35 PM
Subject: [TekScopes] Re: Tek 2753P Manuals

So, I found some manuals for a 494AP which is similar to mine. Also found
some 494 repair notes which looks to be a good find. Anyway, I finally got
around to powering it up with a dim bulb circuit and a 200W bulb. A couple
LEDS on the front came on and the scope backlights but that is it. The bulb
in the test circuit also lit to about half brightness I would guess, not
sure if it's safe to hook up to the variac and get some power board
voltages??? Got the case off, very nice and clean inside, good sign. One of
the main filter caps has the plastic a little ruffled on top so maybe that
got a little hot at some point. Having a little difficulty getting to the
power board, not sure if the go by from the 494 is the same so I am kinda
hesitant to go any further trying to disassemble it. Hoping it's just a few
electrolytics to replace get her up and going. The downside to this unit is
that it is a huge beast of a machine. Have no clue where I will set this up
if I ever get it going.

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