• Please review our updated Terms and Rules here
  • Exhibitor application for VCF West 2022 is now open! If you are interested in exhibiting, please fill out the form here.

C.Itoh CIT 100 Maintenance Manual

Chuck(G)

25k Member
Joined
Jan 11, 2007
Messages
39,078
Location
Pacific Northwest, USA
The troubling thing about the caps is that there's no polarity marking on them. To me that says, irrespective of the PCB markings, that they must be nonpolar, which would account for their size. Here's what a 50V 4.7uF nonpolar Elna looks like--note the absence of polarity markings--and that it's marked with the CE(BP) notation--you might want to see what CE(BP) means to Elna. (To the best pf my determination, CE=cerafine series and BP=bipolar. These were bipolar caps treasured for their use in audio crossovers. They're no longer made, but Elna has an equivalent bipolar audio series, as do other manufacturers).

81hEkyKrJSL._SL1500_.jpg


Those capacitor markings aren't put there for decoration! :)
 
Last edited:

dmemphis

Experienced Member
Joined
Oct 4, 2014
Messages
243
Location
Pottstown, PA
That's excellent sleuthing. Probably the two SNAPS I heard were the two offending caps I
installed. :) I'll further research, and obtain some like caps. I do have 4.7uF non polar-
but they are just as small as the polarized ones I used.
I removed both pairs of ELNA caps from the two video boards and measured them,
and reinstalled the best back into the prime board. (which were the two that came off of it).
There was also a 33uf 250v cap that was close to 20% high, I didn't have a direct replacement
and put in a 47uF 250v cap.
With that all done, still no difference in the display.
If I get to it, I'm going to scope the incoming signals and see if they are reasonable,
and I guess follow the path inward from there.
 

Chuck(G)

25k Member
Joined
Jan 11, 2007
Messages
39,078
Location
Pacific Northwest, USA
As far as not getting an image, you might troll some of the documents on bitsavers wtih regard to terminals in general. At the CRT level, they all operate pretty much the same, so that voltage and waveform specs should be in the same ballpark.
 
Top