Hello,
I have some ongoing problems, which are getting worse with time. Namely, the 1 channel DSO type K8031 in the Transient Recorder mode very rarely is stable and record the time event with success. When activated:
it usually shows some oscillations, or,
will oscillate during recording, or,
the starting point is different.
I have done re-calibrations several times with RV1 and RV2, but this has no effect. It is obvious that there is something else wrong, but I cannot pinpoint it. I have also tried different probes, but to no solution. If images of the Transient mode recordings are required for better assesment, please kindly advise.
The product works excellently as an Oscilloscope and I am very satisfied with it. There are no problems in this mode.
I will very much appreciate your kind advise and help in this very frustrating matter.
This may indicate analog-to-digital converter problem.
The transient recorder uses 16MHz sample rate. This sample rate is used in the oscilloscope mode at 10us/div setting.
Does the oscilloscope work OK at the 10us/div setting when the trace is moved across the screen using the y-position setting?
If any spikes seen, then this may indicate AD converter problem and you have to replace the IC4 (TDA8703).
Hi, many thanks for your advise.
I again re-calibrated by using all 4 elements of RV1, RV2, VC1 and CV2 and now the situation is somewhat better. The trace appears, after several tries, at the designated place on the screen, but will show a rising V/s recording for different times (setting is 2s/div). Sometimes it is for 10 seconds, othertime less or more. The trace will then fall to the bottom of the screen and even if I shift the y-position right to the top, it is still at the bottom. It remains there for the same period as recording and then again records normaly with a rising V/s. This is now periodic, but with different times.
As you advised, I checked the osciloscope function at 10us/div and it was OK all the time. I then checked at 4, 2 and 1us/div and on these settings the spikes appeared, when the y-position was moved, but not always.
All the same I have placed an order for a new TDA8703 and will replace it and see if this is the remedy.
I am also wondering if the cause could be the capacitors C2 and C11, which are electrolyte? Please kindly advise.
This problem may be also a PC based.
The recording is controlled by a PC timer. If there at the same time is running some applications in the PC, this may cause problems to the recording.
Are you using the same PC with same settings and software as earlier?
Can you make a test in other PC?
[quote]I am also wondering if the cause could be the capacitors C2 and C11, which are electrolyte? Please kindly advise. [/quote]This is good point of view. Electrolytes may loose their capacity during long period of time.