My brand new DS1054Z does not like me to change timebase - Page 1
Forum section: electronics / repair

author: juno2
author_rank: Newbie
timestamp: September 23, 2019, 05:59:25 pm
content: My brand new DS1054Z 00.04.04.SP4 bd. 0.1.4 looses triggering and input signal nearly every time I change the timebase. Default it almost never shows a signal. It shows a line but picks up nothing from the probe. The exception is when I toggle in another channel displaying two channels. The it is possible to trigger channel one. But if I change input resolution or the timebase it is gone and I have to toggle another channel in again. I hear the relays going and the signal comes back. Sometimes I can get achieve the same by toggling the BW limit. If I hear the relays it is often ok.Anybody else have this problem. ?I dont want to wait anther 2 months+ to send the device back to China and have it back.It behaves similar for the other channels. Seems like an internal link/relay from the preamps does not work consistently. I like to repair this myself and have Dave's schematic hand drawing so far.Martin

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 23, 2019, 06:11:57 pm
content: it sounds like you've set timebase too big and hence reduced sampling rate on higher frequency signal, so you got aliasing. try to reduce timebase several clicks until you get stable signal. remember Nyquist rate is half the signal frequency, lower sampling rate than that = aliasing. or else maybe you can give more details. what timebase? what signal frequency and magnitude? and some pictures may give clearer view.

author: bd139
author_rank: Super Contributor
timestamp: September 23, 2019, 06:20:38 pm
content: Run calibration on it again. I had some weird shit going on a couple of weeks back with the triggering until I did that again.

author: juno2
author_rank: Newbie
timestamp: September 23, 2019, 06:52:04 pm
content: Initially I just power up default an hook probe to the probe compensation signal. Ch1 selected, 1V trig lev 320mV DC. 500us.Changing time base up or down does not matter no signal. Changing input level from mv to Volts same. In with CH2 /3 or 4 relay click and we have signalAfter leaving it on for more than half an hour it sometimes work ok, but then just a yellow line above zero that does not react on my finger on the probe. In with channel4 and bang i triggers ok, out an its gone.

author: juno2
author_rank: Newbie
timestamp: September 23, 2019, 07:10:33 pm
content: When I try calibration the blue progress bar comes up to 7mm and have stayed there for the last 10minutes. I will wait 30min if there is a timeout somewhere.This is second self-cal attempt, same result.After 30min still hangs.

author: bd139
author_rank: Super Contributor
timestamp: September 23, 2019, 07:27:53 pm
content: I would send it back. Include insults relating their mothers to eggs.

author: juno2
author_rank: Newbie
timestamp: September 23, 2019, 07:40:27 pm
content: Send it back ? It took 2 months to arrive, that means maybe 4 new months. can't do that.Can't be firmware I guess, must be relays or bad soldering somewhererelate their mothers to eggs

author: bd139
author_rank: Super Contributor
timestamp: September 23, 2019, 07:55:12 pm
content: Possibly hardware. Mine drifts terribly. I have to recalibrate it weekly. Im not that impressed and thinking about losing it getting Keysight.

author: StillTrying
author_rank: Super Contributor
timestamp: September 23, 2019, 08:40:10 pm
content: Leave the trigger on AUTO not NORMAL while you figure what it's doing, and are you moving the trigger level to about the half height level of the waveform.