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[email protected] jurb6006@gmail.com is offline
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Default Scopes, Horizontal Deflection

Now dammit, I know how a ramp generator works and I know how a relaxation oscillator works, which is what the ramp generator sometimes becomes in a scope. I wish Jim Yanik was around.

I got two. One is a Tek 465B that works but B sweep does not. the waveform that the plates indicates that when switched it IS switching to B sweep but not starting.

The other is a 204, and the main sweep seems to have the same problem. the final amps are fine in both units.

The problem I have with these is actually following the schematics. Seriously, I think if I could print them out on HUGE paper I might be able to follow it. But that is not practical at this time nor is it practical with these schematics the way they are split up.

I hae already got TWO copies of the PDFs so I can have two instances open, because with the new and improved Acrobat Reader it won't open the same copy twice and I haven't been able to find a way to open two pages at the same time in one instance. Having to go from page 250 to page 146 is a bunch of bull****.

But anyway, we got two scopes, kinda similar in design, with the same problem. What is the common problem when the sweep doesn't start ?

I understand the principles of operation, it is just that I can't run their gauntlet. From the time base part go to this board for the triggering, and then this board for the switching of the triggering and then way the out in bum****t Egypt somewhere to trace the signal.

It is just so much of a bitch to follow.

The Hameg is a 204. It works fine in XY mode. There is a slight DC shift when you change the time/div setting, pretty much at the lower ranges.

The Tek is a 465B and actually woks but B sweep does not. It IS switching to B sweep but B sweep never starts no matter what you do. On page 267 of the service manual, Q6036 has the same voltage on all three terminals but does no check shorted. That makes it somewhat suspect but doubtful it causes this problem. I supplies a calibrated voltage to the ramp generator. Generally if you give it a little more voltage you get more ramp. This gets no ramp, just sits there. In fact if the circuit is entirely open somewhere that is pretty much what would happen.

Maybe I should rethink this Q6036.

Any pointers welcome on either scope. I know they ain't the cat's ass but I would like to see them work.