Somewhere I have an extender for these plug-ins. I forget the part number for the extender . I’d be happy to loan it to you if I can find it; I just moved from Colorado back to Florida and haven’t unpacked everything yet.
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On Sep 9, 2018, at 12:49, William Himbert via Groups.Io <email@example.com> wrote:
I've recently purchased a nice 7S12 (with S-52 and S-6) from a seller, which worked fine when he had it but somehow in shipping (or slightly thereafter when I powered it up in my 7904) has acquired a strange problem affecting both the horizontal and vertical deflection. Is there anybody out there that would be able to sell or loan me a 7S12 internal card extender to assist in the diagnosis work when I am ready to get started? (I have to exhaust some basic testing first, along with building another mainframe extender as I only have one now.)
I searched the group for this kind of problem, and I only found one reference to someone who had a problem with both the horizontal and vertical deflection, but nobody responded to their call for help. Interestingly, the front panel SWEEP OUT seems to have a proper ramp (0-10V) and the horizontal card test points look like the right wave-forms according to the service manual, but on the scope screen I can only get 4 divisions of display maximum. All other plug-ins work in the same slots with no problem. At one point I improved the vertical a bit by re-seating all of the components on the vertical board, but then later while diagnosing the horizontal problem I lost most of the vertical deflection again, and the DC OFFSET no longer re-positions the beam up and down. Very odd!
Originally I was thinking that the only thing that could affect both the H and V deflection would be a power rail, but this seems unlikely so far as all of the internal voltages seem ok.