Re: 7B90P: What makes the buttons work?
Hi Dennis , You wont have seen much from me on this group as I usually have little to add to any conversations but :--The jumpers you refer to if I recall correctly dont enable anything as such , what they do is to parallel the dontrol illumination supply with the normal slot supply for 5 volts as the modules overload the 5 v supply . To make this work the illumination control needs to be set to maximum or it will add nothing to the normal supply . As a test bed for the ones I have I added a 5v 2A supply and connected it to the illumination supply connections , in the 7313 there are no illuminated controls so it sits there quite happily until needed .I hope this info helps in some waytoggle quoted messageShow quoted text
On Monday, 12 August 2019, 19:21:01 BST, Dennis Tillman W7PF <firstname.lastname@example.org> wrote:
Tek made four programmable plugins for the 7000 series. They are the 7A16P
and 7A29P vertical amplifiers, and the 7B81P and 7B90P time bases. The 7B81P
never went into production.
These were intended for the digitizing 7000 mainframes. But for calibration
purposes they have to be able to work in standard 7K mainframes.
So all of these programmable plugins have a jumper next to the rear
interface connector that activates the front pushbuttons. By placing a small
shorting plug across the two pins at the rear, the front panel pushbuttons
The only exception is the 7B90P. It has the jumper but the plugin seems to
be waiting for something else as well.
I have tried shorting out all of the possible locations on the 7B90P that
might also be involved but I haven't found the secret to making the front
The preliminary manual (that is all there is as far as I know) is no help.
Has anyone figured out how to get the 7B90P to respond to its front panel
Dennis Tillman W7PF