Tektronix 2213 CRT Modification
Thanks so much, that's exactly the info I was looking for.
Best regards,
Steve
On 14 Jan 2007 22:36:52 GMT, Jim Yanik wrote:
Steve wrote in
:
I have a great Tek 2213 that was purchased form a TV station. The
scope is in great condition, but CRT is very dim. IIRC, I've read
that these scopes had a slightly high filament voltage resulting in
short CRT life, and there was a mod that Tek did to fix this problem
by removing a few turns on the XFMR. Is this right?
Yes;a half-turn was removed from the T940 inverter xfmr's HV filament
winding,the brown wire at the top of the bobbin.
You have to re-adjust the CRT grid bias after the mod is done.
I also remember
someone saying that there was a marking on the back of the scope or
the xfmr if they had been modified. Well, I found a replacement CRT
with plenty of life left in it, but I don't want it to fail
prematurely again. Is this a user modification, or is it pretty
lenghty? Any info on this subject appreciated.
Thanks,
Steve
CRT filament mod 2213 S/N range; B010100-B029389,200001-203411
Modded scopes should have a Tektronix ID Number label on the rear
somewhere;M50226 is the Mod number.
S/N's B027000-B030000,202500-203411 should be checked for prior
modification BEFORE implementing the mod.
IIRC,inverter xfmr's with an -01 suffix will already have the mod.
from my schematic peniclled-in notes,CRT fil voltage ;
**measure disconnected from PCB!!** (true-RMS meter)
unmodded 7-7.3 VRMS
modded 6.1-6.4 VRMS
2X mod 4.4-4.6 VRMS (2X= mod mistakenly done twice)
--
Jim Yanik
jyanik
at
kua.net
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