Re: Displayed signal becomes compressed when position is moved to the left
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I see. The switching is external. That makes sense now. Yes the pull down is there. I moved the collector over to see what effect it had and there was a greater phase shift. I guess they opted to tim them together to eliminate the shift. ? ?
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From: TekScopes@... [mailto:TekScopes@...] On Behalf Of David
Sent: Saturday, February 11, 2012 2:40 PM
To: TekScopes@...
Subject: Re: [TekScopes] Re: Displayed signal becomes compressed when position is moved to the left? ? If mine are like that I have not noticed. Functionally it should not
matter which sweep inputs are used since the sweep signals are current
switched using CR742 and CR732 externally which is exactly how U760 is
designed to operate so they could both go to one or to the separate
sweep inputs. In a dual timebase design like a 4 bay 7000 series,
each timebase bay would go to a separate input I think. The
155-0124-00 horizontal preamplifier is in the Tek-Made Integrated
Circuits Manual.
The unused input should be pulled low. Isn't R733 still in place?
On Sun, 12 Feb 2012 00:20:45 -0000, "david_s5y" <david_s5@...>
wrote:
>There was one oddity. That does not match the schematic. But it looked like it was done in the factory. The collector Q732 had it's collector tied to Q742's collector and pin 10 does did not have any signal on it , yet delay works fine. Is yours like that too?
>
>David
>
>--- In TekScopes@..., David <davidwhess@...> wrote:
>>
>> The storage and readout vectors are inserted between the horizontal
>> preamplifier and the horizontal output amplifier so the problem will
>> be the horizontal multiplexor on schematic 7 or earlier. The
>> horizontal output amplifier should be fine. I suspect the sweep
>> outputs up to U760 are fine as well.
>>
>> As a test, switch the oscilloscope to delayed mode and see how the B
>> timebase which uses a separate parallel circuit path works.
>>
>> What are the marked voltages around the horizontal multiplexor in
>> store and non-store mode? What are the marked voltages around U760 in
>> store and non-store mode?
>>
>> On Sat, 11 Feb 2012 18:07:21 -0000, "david_s5y" <david_s5@...>
>> wrote:
>>
>> >I have repaired the storage functions and am now trying to resolve this display issue.
>> >
>> >Here is a video
>> >
>> >That shows the issue. It only appear in NON-Store mode.
>> >
>> >I start in Store mode and show it works, then switch to NON store show the issue and then change the time base and then return to store.
>> >
>> >Since it works in Store mode am I correct to think that rules out the physical connections at the CRT?
>>
>> That rules out the physical connections to the CRT and also rules out
>> the horizontal output amplifier.
>>
>> >But can the CRT output amplifier be going into limiting for only the non store?
>>
>> No.
>>
>> >How is the horizontal timing generated?
>>
>> In non-store mode it is generated in the A sweep generator (schematic
>> 5) and in the B sweep generator (schematic 6) but neither of those
>> have anything to do with the position control.
>>
>
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