Tek 475 Restoration
1/20 2019
I seems like kind of addicted to get Tek stuff. This Tek-475 only sell to local buyer with good discount, 40$ only, per seller's description, it's all working but aging. luckly I could testing this gear right at seller's office.
The machine is pretty dusty, sticky. The couple switch is so hard to movement. One of them is loosing, could not change the couple switch anymore.
This Restoration turns to be just a clean up and fix sticky switches. There is no any electronic fault, every thing is work just fine.
After get this baby to home, first thing is take of the cover, checking it around. The board is not too bad, after bath with 95% alcohol, it looks pretty.
The Vertical board is removed, the DM44 also been lift up, in this way, the Time/Div Knob could be reached and loose the internal screw. so i could given this a toughly clean up. The attenuator board is prety hard to take off, I just give up. cause i already fix the couple switch.
And after do several round clean use alcohol, via any crack i can find, all sticky switch is free as new again.
All knobs taken off, and the aluminum panel been removed carefully, brush them until they looks pretty enough.While all of these done, it's beter use a air dryer blow every inch, evaporating remain alcohol.
The triggering circuits must be aging, it does need one minutes warm up to get a clean waveform, other wise, the sweeping line is flicking a little bit. Another aging symptom is that the vertical amplifier seems easy be interfered by something, and only 5 mv/Div or 2 mV/Div could notice that.
There might some capacitors need replacement, i rather leave it escalating till i can not stand it.