7704a repair adventure


Windsor Chan
 

Hello gang,

Today I aquired a 7704a from a surplus store. I inserted a 7a26 and a
7b80 and found that the vertical was deflected way off the top, only
visisble when beam finded was on. Fortunately I had a reasonably good
working 7704a. The nice thing about the 7704a is that the "head" is
removable. So I did a head swap. On the new 7704a the problem
remained and the old 7704a still worked with the new display section.
So without the manual I thought what could go wrong? I pulled the
readout board to no effect. Then I look at other 7xxx family manuals
for inspiration.
Then I swaped the pair of delay line driving transistors and BINGO! :)
Now the vertical deflection is operating good. Then I looked up Stan
and Bill reference site and found that 151-0269-00 = FMT1061 .

Then I looked at my ECG semiconductor replacement guide, no matches.
Then googled FMT1061. No matches.

The question I have is what are the characteristics of the
151-0269-00 ?


Thanks

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