Will my dsoshell 15001k be ok after giving it 18v instead of 9v?

[snow]

hey y'all, (not sure if this is the right place to post this) i just finished building a DSOshell 15001k DIY oscilloscope kit, and to test it, i accidentally used an 18 volt power supply instead of a 9 volt one. will it still be ok? or will i have to get it swapped out? i didnt hear any components pop or anything.

[snow]

and if you're wondering why I gave it 18v instead of 9v, its 'cause I play guitar and I had a daisy chain power supply wall wart laying around, and I used it 'cause I thought it was a 9v PS, but it's and 18v PS. but I didn't check to see if it supplied 9v before using it.

[Manul]

will it still be ok? or will i have to get it swapped out? i didnt hear any components pop or anything.

I don't really understand a question. Either it was not damaged and it works or it was damaged and it does not work. Have you tried? Does it work?

Generally speaking the result of such event depends how the device is designed and what parts were used. This one seems to have only the LM1117-3.3 linear voltage regulator powered by 9V. LM1117 absolute maximum is 20V I think and it also has thermal protection. So all should be ok.

[tunk]

The ICL7660 doesn't like more than 10.5V, and if it's an unregulated
18V supply, the light load voltage could be well above 20V. Look at the
schematics below and measure the test points.
https://jyetech.com/dso-150-shell-oscilloscope/

[Manul]

The ICL7660 doesn't like more than 10.5V, and if it's an unregulated
18V supply, the light load voltage could be well above 20V. Look at the
schematics below and measure the test points.
https://jyetech.com/dso-150-shell-oscilloscope/

That's a good point, I've totally missed the "analog" part of the schematic. Situation does not look so good anymore. At least ICL7660 is not a big deal and can be replaced.

[snow]

will it still be ok? or will i have to get it swapped out? i didnt hear any components pop or anything.

I don't really understand a question. Either it was not damaged and it works or it was damaged and it does not work. Have you tried? Does it work?

Generally speaking the result of such event depends how the device is designed and what parts were used. This one seems to have only the LM1117-3.3 linear voltage regulator powered by 9V. LM1117 absolute maximum is 20V I think and it also has thermal protection. So all should be ok.

well it works (i havent really messed with it yet, it just turns on and the controls work), but the on/off switch doesnt seem to do anything.

[Manul]

well it works (i havent really messed with it yet, it just turns on and the controls work), but the on/off switch doesnt seem to do anything.

On/off switch seems to be bypassed in schematic. Don't ask me why. You can remove R30 (0R jumper resistor). Does it show signals properly? If yes, then it survived. As tunk noted, the negative voltage generator was the most likely to fail. In that case I assume it would work, but would not show signals properly.

[snow]

well it works (i havent really messed with it yet, it just turns on and the controls work), but the on/off switch doesnt seem to do anything.

On/off switch seems to be bypassed in schematic. Don't ask me why. You can remove R30 (0R jumper resistor). Does it show signals properly? If yes, then it survived. As tunk noted, the negative voltage generator was the most likely to fail. In that case I assume it would work, but would not show signals properly.

how can i test if it shows signals properly?

[snow]

well it works (i havent really messed with it yet, it just turns on and the controls work), but the on/off switch doesnt seem to do anything.

On/off switch seems to be bypassed in schematic. Don't ask me why. You can remove R30 (0R jumper resistor). Does it show signals properly? If yes, then it survived. As tunk noted, the negative voltage generator was the most likely to fail. In that case I assume it would work, but would not show signals properly.

and it turns out r30 bypasses the on/off switch

[Gyro]

The TL082 / TL084 opamps should be ok as they are rated to survive  +/-22V (assuming that the 7660 output actually made it to anywhere near -18V). The LM1117 regulators in these things have been reported to fail sometimes (potentially non-genuine), but if this one survived the overvoltage then it's probably not a weak one. The other things that would have suffered significant overcurrent are the display backlight LEDs which are fed from the unregulated supply. If the display is still illuminated evenly then they should be ok. Many of the electrolytic caps are also not rated that high - check for any bulged ones.

how can i test if it shows signals properly?

In the absence of other equipment, connect the probe tip to the 1kHz output, set the coupling to AC, and check that you get a symmetrical square wave about 0V. Check that you get a nice stable trigger on rising and falling edges. Run through the sensitivity ranges and check that the waveform gets bigger (reaching over full scale) and smaller appropriately.

[snow]

In the absence of other equipment, connect the probe tip to the 1kHz output, set the coupling to AC, and check that you get a symmetrical square wave about 0V. Check that you get a nice stable trigger on rising and falling edges. Run through the sensitivity ranges and check that the waveform gets bigger (reaching over full scale) and smaller appropriately.

is this what is supposed to happen?: https://imgur.com/a/TsCsN4Q

[Gyro]

(It's always worth attaching images to your posts, external links inevitably become orphaned over time.)

No, that doesn't look right. It seems to be showing a large negative offset on the waveform. Strangely the waveform looks to be roughly the right size (on 5V/div) but it should be centred on the channel position marker (green arrow on left hand side of the screen). With the 1kHz input removed, you should also get a flat line which lines up with the marker.

Try moving the trace vertical position and see if it moves at all. Off the top of my head, it may be that the positive supply to the analogue board opamps has failed.

[snow]

Try moving the trace vertical position and see if it moves at all.

how do i do that?

[Gyro]

Best that you read the instructions to familiarize yourself with its intended operation. That will speed up your fault-finding and understanding what isn't working properly.

[snow]

Best that you read the instructions to familiarize yourself with its intended operation. That will speed up your fault-finding and understanding what isn't working properly.

ok, i did the VPos allignment, but the vpos still like to move around alot

[Gyro]

It sounds as if it's time to get the meter out and establish what is happening to the supplies on the ICs on the analogue board. If the supplies are all ok, then it may be a damaged IC. It's probably best to look around the U5 (the ICL7660) but there could be a problem anywhere, for instance, burned out R26 or R27 or damaged electrolytic caps downstream of them.

At least t looks as if the 3V3 logic supply to the CPU and display is ok. Other parts are cheaper and easier to replace in comparison.


EDIT: When you say "but the vpos still like to move around alot" maybe the probe is picking up noise. Try shorting the probe clips. Also check again to see if you get a symmetrical (AC coupling) squarewave waveform above and below 0V (the green arrow).

[snow]

EDIT: When you say "but the vpos still like to move around alot" maybe the probe is picking up noise. Try shorting the probe clips. Also check again to see if you get a symmetrical (AC coupling) squarewave waveform above and below 0V (the green arrow).

i removed the clip from the probe and now the VPos isnt moving around nearly as much, but it is still slowly going down a bit.

[snow]

voltages:

V+: 5.6
AV+: 4.2
V-: -4.9
AV-: -4.1
V1-V3: 0
V4: 1.3

[Gyro]

If V+ is only 5.6V then it indicates that you are not feeding the board with 9V (more like 6.4V). The logic supply is regulating ok and the +/-AV voltages indicate that the 7660 -ve rail generator is working and there is no excessive current drain on the Analogue board. Maybe your (unregulated) 9V adapter isn't rated for sufficient output current.

Feed it with the correct voltage and the trace will probably stabilize!

[Peabody]

Your DSO150 is a newer version than mine, but to reset the vertical position on mine, I disconnect the leads, move the input switch on the back to GND, then hold the left button down until it says it's resetting the vertical.  That moves the left indicator to the middle, and that's also where ground is.  Then I move the input switch back to DC and test the squarewave generator on the back, which should give you a square wave from ground to 3.3V.  I don't know if the newer versions work the same way.

[snow]

If V+ is only 5.6V then it indicates that you are not feeding the board with 9V (more like 6.4V). The logic supply is regulating ok and the +/-AV voltages indicate that the 7660 -ve rail generator is working and there is no excessive current drain on the Analogue board. Maybe your (unregulated) 9V adapter isn't rated for sufficient output current.

Feed it with the correct voltage and the trace will probably stabilize!

yea rn im just using a 9v battery with a battery clip thingy

[snow]

for some reason my truetone onespot power supply isnt working with it, but the battery clip does work.

[snow]

and the battery is at about 8.5v

[Gyro]

Your battery is probably 8.5V open circuit, but is dropping significantly (to around the 6.xV figure when under load - maximum voltage drop of a 1N4007 diode is around 1.1V at it's full 1A rating (so less in your case).

I can't comment on why your mains adapter isn't working. Maybe it isn't rated for enough current and sags too low, maybe it has excessive ripple (Have you checked the polarity of its output even?).

The little 9V battery won't survive for long (it is failing already). If you want a portable setup, you would be better to get a 6xAA battery holder. That ought to give reasonable battery life.

There is a thread on the JYE forum about using alternative battery sources, including internal lithium - but I really wouldn't advise that at your level of experience.

https://forum.jyetech.com/viewforum.php?f=19&sid=0d35785e52febca7607085b79162322d

[m3vuv]

I honestly dont know why people bother with these chineese toys that are like sommat that fell out of a christmas cracker!