HELP: Broken Rigol DS2072 or i am only to stupid to use..... - Page 1
Forum section: electronics / beginners

author: Zh4ng
author_rank: Unknown
timestamp: April 03, 2014, 04:57:39 pm
content: Hi there,I think I'm too stupid to use to the device. On channel A, I can move the trace with the knob up and down vertically. When I press the button, channel A is reset. So far so good. While on channel B does the reset, but I can not move the trace vertically. Is there a trick or is the scope broken?thx Zh4ng

author: miguelvp
author_rank: Super Contributor
timestamp: April 04, 2014, 01:37:36 am
content: I can't get mine to not work so might be broken.Things you can try is:Storage/Default (That will reset everything back) Including your ratio to 1XAuto, might clear some thresholds, not sureUtility/Self-Cal and let it self calibrate.But like I said, I couldn't make mine stop responding to the vertical position but didn't try too hard either.

author: Zh4ng
author_rank: Unknown
timestamp: April 04, 2014, 09:47:58 am
content: Okai, i contact the Reseller. It seems to be broken.Shit......Let's see how long will the repair.

author: miguelvp
author_rank: Super Contributor
timestamp: April 04, 2014, 09:54:03 am
content: Quote from: Zh4ng on April 04, 2014, 09:47:58 amIt's just an optical encoder, maybe some dust or a loose connector. Should be a quick repair I hope.

author: Hideki
author_rank: Frequent Contributor
timestamp: April 04, 2014, 10:16:12 pm
content: Dave also likes calling them optical encoders, but no... I would say that in the overwhelming majority of cases involving front panel encoders, the switching is purely mechanical -- NOT opticalOptical encoders do exist, but the typical price is ten times higher or more, so the chances of seeing them in a Rigol product is slim to none.

author: miguelvp
author_rank: Super Contributor
timestamp: April 05, 2014, 01:48:30 am
content: Quote from: Hideki on April 04, 2014, 10:16:12 pmThanks, just looked it up and you are of course right, mechanical encoders can be found for $0.50, optical ones go for $7 and magnetic encoders go for $20 in large quantities.I always thought they were optical since they don't stop and just count, but it makes sense the vertical knob is not optical since it seems continuous. The scale on the other hand and the rest of the knobs that you can feel the steps do 19 steps per turn.I guess I'm used to pots to stop at maximum resistance like in the old days and anything that keeps on turning must be not mechanical in my head

author: Rigby
author_rank: Super Contributor
timestamp: April 05, 2014, 02:31:44 am
content: Does that scope do Ground coupling? If it's coupled to ground then it won't move.

author: miguelvp
author_rank: Super Contributor
timestamp: April 05, 2014, 03:16:48 am
content: Quote from: Rigby on April 05, 2014, 02:31:44 amIt does Ground Coupling and the vertical encoder moves it.But Storage/Default clears all the settings and he couldn't get to move it.Also the Auto button clears the ground coupling as well.

author: vk6zgo
author_rank: Super Contributor
timestamp: April 06, 2014, 03:21:21 am
content: Quote from: Hideki on April 04, 2014, 10:16:12 pmYaesu.Icom,Kenwood,etc,have been using optical encoders since the mid 1970s,so I fail to see why Rigol can't.If you buy,(or make) these things in their thousands,the cost differential becomes quite small.

author: Rigby
author_rank: Super Contributor
timestamp: April 06, 2014, 03:31:44 am
content: Quote from: vk6zgo on April 06, 2014, 03:21:21 amremember the computer mice with the balls that fed mouse movement into the circuitry of the mouse? those terrible things that got gunked up all to hell after a while? two optical rotary encoders per mouse. optical encoders are dirt cheap, and they have been for a very, very long time.

author: vk6zgo
author_rank: Super Contributor
timestamp: April 06, 2014, 03:50:32 am
content: I thinkHidekiis thinking about the high precision "absolute" encoders used in Robotics,etc.When I Googled I got a lot of stuff about them,rather than the things we normally think of,& refer to, as "optical encoders".Positional accuracy doesn't matter much with an optical control,as long as it reads the correct digital word when it is needed.

author: Nerull
author_rank: Frequent Contributor
timestamp: April 06, 2014, 03:58:53 am
content: Quote from: miguelvp on April 05, 2014, 01:48:30 amMechanical encoders don't work like pots - they send pulses just like optical encoders, they're just generated by electrical contacts instead of optical sensors. From a user perspective, its unlikely you could ever tell the difference between them. Mechanical encoders have to be debounced and don't work as well at high speeds, but thats a problem for engineers not end users.Clicking into place is done by detents, and has nothing to do with the type of encoder or pot.The encoders in the ds1052e are mechanical, at least.

author: miguelvp
author_rank: Super Contributor
timestamp: April 06, 2014, 04:10:46 am
content: I know that, that's why if they stop I think of them as pots, if they don't stop then I think of them as optical encoders.And since the one in question is continuous as in it sends a lot of pulses per turn, they must not be optical since those ones cost 10x more than the mechanical ones and the magnetic ones cost 40x more than the mechanical ones.Now if it was the Scale knob, that has 19 pulses per rotation, well, that one can be done with a cheap mice like optical encoder. But for the fine grain position knob, it must be mechanical.Edit: Those 19 pulses might be detents like you mention, but they correspond to the input. But that could be part of the counter hardware.In any event, it could be the connector to the main board that is at fault or the chip behind the encoder. Most likely they'll replace the input board and call it a day.