It may not give any immediate clues but you can try B-sweep with sine wave and see if the jump is there in B-trigger too. B side is very similar to A trigger.?
Since you have other scopes, you can feed in same sine wave to both this unit and a second scope, and trigger both with same sine wave. On the second scope use channels 2 and 3 to look at U421C (sheet <3>) pins 25 and 26. Pin 26 is the final result of trigger processing and pin 25 is the trigger level. If one of them jumps vertically (on the second scope it won't shift horizontally) then you can trace back from that point. If they both look stable issue most likely is downstream from U421C.
Ozan
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On Wed, Jul 12, 2023 at 07:41 AM, Alex wrote:
Ozan:
yes the jitter is still there when feeding a sine wave and trig mode set to NORM.
Dave:
Yes both sine and square wave signals are from the same generator which really has two independent outputs (Heathkit IG-18). I also simultaneously verified the output of the generator with my other scope and the jitter is only shown on the 2247A.
Yes the jitter is still there when feeding a 1Khz sine wave, and with HF Reject trigger mode.
To me the 2247A is the best scope, tremendously flexible and feature rich with lots of CPU driven useful measurements. It gets picked first on 95% of the cases. The 2265B usually just because higher than 100MHz bandwidth is required, or to quickly cross check something. I also have a 222, and a 2213A, but those really don't get used much. I've had the 2247A now for 11 years, got it used off ebay and all it needed back then was to replace the internal Lithium battery that only stores the last used configuration.
