Scopes, Horizontal Deflection

Now dammit, I know how a ramp generator works and I know how a relaxation o scillator works, which is what the ramp generator sometimes becomes in a sc ope. 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. Serious ly, I think if I could print them out on HUGE paper I might be able to foll ow it. But that is not practical at this time nor is it practical with thes e 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 cop y 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 bullshit.

But anyway, we got two scopes, kinda similar in design, with the same probl em. 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 i n bumfuckt 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 wh en 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 t o B sweep but B sweep never starts no matter what you do. On page 267 of th e service manual, Q6036 has the same voltage on all three terminals but doe s no check shorted. That makes it somewhat suspect but doubtful it causes t his problem. I supplies a calibrated voltage to the ramp generator. General ly if you give it a little more voltage you get more ramp. This gets no ram p, 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.

Reply to
jurb6006
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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 bullshit.

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 bumfuckt 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.

+++++++++++++++++++++++++++++++++++++++++=

Do you have waveform 73 on schematic 8? That is the B start gate. Start there.

Reply to
tom

With any old-school-scope repair, it is sensible to check out all switch and header contacts for corrossion problems, before getting bogged down in circuit minutei. The "well it was working fine, before I left it on the shelf for a year" scenario.

Reply to
N_Cook

Uh-Oh. Something happen to Yanik?

Mark Z.

Reply to
Mark Zacharias

I think so, life. I think if he is alive now he is probably about 98 years old.

I would have liked to have met him and had a couple brewskis. I mean really, and you might as well know that I have no desire to meet any President of the US within my lifetime, and then some.

Yanik was super sharp with scopes. You ask a question and he says "that is a 100K ceramic, R401 which is on the left side behind the big blue thing in the middle of the board". Some shit like that.

I got that good with TVs but they don't go for ten grand.

Reply to
jurb6006

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