EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: OldSchoolTechCorner on August 27, 2015, 06:50:39 pm
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Restoring a old Tektronix 212 oscilloscope that I won off eBay. Very limited usefulness as Its top bandwidth is 500 kHz and it's maximum vertical sensitivity is 1 mv/ div. Bought it due to it unique size and to mess around with. When I received it, didn't want to power on, only red LED lit, so checks voltages and were OK and then spray contacts and pots with deoxit and pots with fader lube and came to life. Does have issues with is to be expected due to age, but at least for now triggers on both channels, which is a good sign. Will do a full rebuilt and bring back up to specs and rebuilt both battery packs as uses two 5 cells packs. Good thing is they didn't leak all over the place.
(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_124117_zpsgbrzlacu.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_124117_zpsgbrzlacu.jpg.html)
(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_124450_zps3x3rw6ic.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_124450_zps3x3rw6ic.jpg.html)
(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_130700_zpsychmdlkb.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_130700_zpsychmdlkb.jpg.html)
(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_130833_zpspgrqmduq.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_130833_zpspgrqmduq.jpg.html)
(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_131019_zpsf93pfauo.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_131019_zpsf93pfauo.jpg.html)
(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_131300_zps1ye8yyon.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_131300_zps1ye8yyon.jpg.html)
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The tear down
You have to remove also this plastic screw for mid CRT support, before removing CRT
(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_140747_zpsrxhexc46.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_140747_zpsrxhexc46.jpg.html)
The two 5 cell battery packs
(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_140902_zpsidp9lruc.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_140902_zpsidp9lruc.jpg.html)
(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_141104_zpszofgjamh.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_141104_zpszofgjamh.jpg.html)
(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_141218_zpsaupjbzev.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_141218_zpsaupjbzev.jpg.html)
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(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_142121_zpsi1ue7ddl.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_142121_zpsi1ue7ddl.jpg.html)
(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_142146_zpstckleyjm.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_142146_zpstckleyjm.jpg.html)
(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_142159_zpswneom7mn.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_142159_zpswneom7mn.jpg.html)
(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_142430_zpsjgo7b8yu.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_142430_zpsjgo7b8yu.jpg.html)
(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_142455_zpszj4p1zp3.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_142455_zpszj4p1zp3.jpg.html)
(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_142514_zpsvl0s4w9k.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_142514_zpsvl0s4w9k.jpg.html)
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Very nice; I have a Tek portable scope in the garage I should do a tear down on. it works and is mid to early 1960s vintage. :)
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It back together for now. So now works perfect. Have to wait for some NiCd batteries to show up and then work on the battery packs. Capacitors have good ESR and tested within specs and when though calibration on service manual and was dead on. So no point in changing any components for now. Only issue it had was dirty switches and dead battery pack.
(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_170226_zpsutziucrb.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_170226_zpsutziucrb.jpg.html)
(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_172326_zpsyqheodye.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_172326_zpsyqheodye.jpg.html)
(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_193152_zps77qyy1lb.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_193152_zps77qyy1lb.jpg.html)
(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_205531_zpsd7vxtx6v.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_205531_zpsd7vxtx6v.jpg.html)
(http://i1220.photobucket.com/albums/dd456/retropcdos/20150827_212056_zpsy6n1awna.jpg) (http://s1220.photobucket.com/user/retropcdos/media/20150827_212056_zpsy6n1awna.jpg.html)
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I cannot see one picture here... |O
The µTek, 200 series have oftenly problems with destroyed boards by acid from bad batteries. So clean the ground board very good.
This little scopes was not made for high bandwith. They have other specifications. Look for the sensitivity min. and max. !
there was five different types:
the 211, a single channel .5mc
the 212, a dual channel .5mc
the 213, a single channel 1mc with onscreen DMM (reading true RMS also, directly from the probe!)
the 214, is a 212, but it have a storage CRT, very nice
the 221, a single channel 5mc
I need a 211 t complete the little family here :)
picture: 212, 213, 214, 221, 222 (DSO)
(http://www.wellenkino.de/214/214-1.jpg)
greetings
Martin
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I cannot see one picture here...
+1
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Hardly a workaround, but you can click on each picture to view it on Photobucket. :-/O
Those hand-routed boards look really funky to me, thanks for sharing (and lucky the batteries didn't leak)! :-+
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when you get a little 212 and you think that is so slowly and not useful today,
there is some collecting people who will give 100$ and more for that scope.
This scopes was a luxury bad expensive test equipment for engineers with enough money. So they are rare, not oftenly saled.
here are the US catalog prices for new Tek 212 :)
1974 $725
1975 $755
1976 $875
1977 $1000
1978 $1080
1979 $1190
1980 $1350
1981 $1475
1982 $1545
1983 $1710
1984 $1775
1985 $1895
1986 $2045
1987 $2095
1988 (not listed, end)
greetings
Martin
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Bummer about the photobucket ripoff scam.
Download anything of value to you, it may fade away on the internet aka Animal Farm book.
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Bummer about the photobucket ripoff scam.
Download anything of value to you, it may fade away on the internet aka Animal Farm book.
Or better upload pics as attached files to the forum, open them in separate windows to get picture links, and finally insert the links as pics to your text. ;)
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Then Dave will get abducted by aliens. history of pictures kindled at 451 degrees yank, Maybe even probed.
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Hello.
I now own this Tektronix that slept in the closet with friends. I have to change the batteries that are dead.
In Europe the current is 220 Vots. I believe there was a specific version for this voltage.
How to be sure that this is not the 110 Volt version?
Is there a point of information somewhere to avoid toasting it?
Thank you. :)
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Please re-publish all pictures with the photobucket overlay.
They blurr all technical details.
Genius @work?
Thanks, Frans
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BE AWARE, the batteries charge by being capacitively coupled
to the A.C. Line!!!! Never plug the scope in without good batteries
in place and be aware of the weird things the scope will do if
plugged in to an improperly polarized socket, the fat blade is
ground!!!.