Search found 78 matches

by davef
Mon Jul 06, 2015 12:14 am
Forum: DSO138
Topic: New kits - 13803/4K - F/W .050
Replies: 43
Views: 51557

Re: New kits - 13803/4K - F/W .050

Which area of the board would it be most appropriate to photograph?
by davef
Sun Jul 05, 2015 11:17 am
Forum: DSO138
Topic: Has anyone updated their dso138 to make it better?
Replies: 5
Views: 7741

Re: Has anyone updated their dso138 to make it better?

046 is on their website
by davef
Sun Jul 05, 2015 11:13 am
Forum: DSO138
Topic: New kits - 13803/4K - F/W .050
Replies: 43
Views: 51557

Re: New kits - 13803/4K - F/W .050

MorganFlint, You are correct. After I shut the computer down I thought I had got it wrong. I had a look through board.c and couldn't spot what I was looking for. However, we use the STM32 series at work so I'll talk with the guru. Also, bought mine from Banggood. There is one outfit (taibo?) selling...
by davef
Sat Jul 04, 2015 10:45 am
Forum: DSO138
Topic: Wrong resistors ( may i burn it ? )
Replies: 3
Views: 6001

Re: Wrong resistors ( may i burn it ? )

Not obvious to me that wrong values for those components would cause your problem. Suggest you have made another mistake. Did you not use the SMD resistors supplied in the kit?

The resistors you mention would have some effect of the gains of the various stages, not their operating points.
by davef
Sat Jul 04, 2015 10:40 am
Forum: DSO138
Topic: New kits - 13803/4K - F/W .050
Replies: 43
Views: 51557

Re: New kits - 13803/4K - F/W .050

So, by reducing the gain of U2C significantly and doing something in S/W (maybe ADC setup) they manage to reduce the noise artifacts considerably.

Seems something else has to suffer here, ie resolution or ?
by davef
Tue Jun 23, 2015 8:48 am
Forum: DSO138
Topic: Firmware 113 13801 046
Replies: 1
Views: 4167

Firmware 113 13801 046

The unit I received from banggood.com has firmware version 113 13801 046

Are they any new features with this version?

Thanks,
Dave
by davef
Tue Jun 23, 2015 8:41 am
Forum: DSO138
Topic: Circuit modifications
Replies: 0
Views: 4620

Circuit modifications

Noticed a significant droop on low frequency square waves, say 10-100Hz. Changed C1 to a 1uF 50V mylar. Next, if thought I have a look at trying to get rid of the artifacts (noise spikes) which I see on the 1kHz test signal at a timebase setting of 0.5ms. With another oscilloscope and probing around...
by davef
Sun Jun 21, 2015 10:48 pm
Forum: DSO138
Topic: Assembly and calibration hints
Replies: 0
Views: 4074

Assembly and calibration hints

Leave protective plastic sheet on display until everything is working. This will protect the screen from any marks caused by solder splashes, etc. Be careful when inserting the LCD module. Apply even pressure on both ends on the 40 pin header whilst guiding in the two 2 pin connectors. Adjusting C6 ...