Having issues with channel one on my Siglent scope, is this hardware?

[rwgast_lowlevellogicdesin]

Ok so a sound card puts out awful square waves at any frequency but with some I can clearly tell the wave form distorts in between 60-65hz, that is when the rising edge disappears and it becomes more of a triangle/sin wave. Sin wavs seem to look fine but a I get faster well into the khz range they skew a little bit on the falling edge in a subtle sort of concave manner.

Is it coincedence that this problem starts about the same frequency as the mains voltage?

[2N3055]

Sorry if I'm asking the obvious but there is button "Default setup" that should reset all the user interface setting to defaults...

[DimitriP]

I have some old rack mount HP analog but it is only 500khz so I dont think that will help me at all.

If you are trying to trace a 1KHz signal, it should work just fine. (if that's indeed a "rack mount" 500Khz scope- check again!)

Feed both channels with  1KHz and then use your 500KHz scope to trace the signal, comparing ch1 with ch2.
Buit if there is a chance it's under warranty, you should probably wait to know for sure before you start tearing it apart.

[rwgast_lowlevellogicdesin]

I have repeatedly said I have hit the default set up button at least 5 times...

Im positive the scope is 500khz, its a huge beast. I cant even fit the thing on my desk id sell it if it were worth anything I figure its good for audio. I see people trying to get 300 bucks for it on e-bay I have no idea what there thinking... If I could get that I would sell it in a heart beat a signal gen or to put twords a LimeSDR

http://www.radiomuseum.org/r/hewlett_pa_oscilloscope_1200_b1200.html

http://www.ebay.com/itm/HEWLETT-PACKARD-1200B-OSCILLOSCOPE-100uV-DUAL-TRACE-500KHZ-/281860857463

[StillTrying]

I have repeatedly said I have hit the default set up button at least 5 times...

Actually, hitting the 'Math' button 5 times, might do some resetting or something.

[tautech]

@ rwgast_lowlevellogicdesin
Your issues have been handed to Siglent USA, there will be less of a difference in time zones in order to find a solution for you.
Expect contact from them.

[villas]

I have a working 1022DL, let me know if there is something I can check on my unit to compare.

[sdrocco]

At Siglent America we have not seen a problem like this before on any of our oscilloscopes. The SDS1022DL was never sold through the US office, but in my opinion it looks like a hardware problem. If you would like you can contact us at info@siglent.com.

[tautech]

At Siglent America we have not seen a problem like this before on any of our oscilloscopes. The SDS1022DL was never sold through the US office, but in my opinion it looks like a hardware problem. If you would like you can contact us at info@siglent.com.

Welcome to the forum Scott.

Yes, I've not seen the likes of this problem before either.
Is it possible rwgast_lowlevellogicdesin can be offered a 1052DL mainboard?

[rwgast_lowlevellogicdesin]

Well thanks for getting back to me guys :/. Sucks this is hardware.

[StillTrying]

So what's the plan now. I had a good search for a schematic, I didn't try for ATTEN versions though.

[DimitriP]

Time to take it apaaaaht !

[DimitriP]

Found the "Service Manual" but it doesn't include a schematic. Genius!!!

Still, Ch1 and Ch2 are "twins".
You should be able to compare signals to find out where the signal gets lost. So lug that 500KHz scope out and fire it up.

[rwgast_lowlevellogicdesin]

Im going to call siglent today and get a few answers about compatible motherboards, warranty etc. Im afraid to take an iron to the mobo having a 1 channel scope is better than a no channel scope. Looking at the pictures posted im not sure this repair is in my league yet. I will get my siggen back today so I can run some better tests, if worst comes to worst I may open it up and try to trace the signal with my other scope but i trying to avaoid poking around in it.

I seriously thought that this would be a problem with some of the filtering hardware in the front end but the fact that it starts at 60hz from what I can tell is just to coincidental.

[BravoV]

Your scope is already out of warranty right ? Are you saying Siglent willing to repair or even better send you a new board "for free" ?

[rwgast_lowlevellogicdesin]

No... I'm not sure of anything I'm going to call and figure out my options. I doubt anything will be free, but if I can use other motherboards in the same chassis with the same screen/controls that opens up a lot more options.

[DimitriP]

Open it up already

[tautech]

Open it up already

Why ? 

There won't be anything different to see than in the pics in reply #21.

If rwgast_lowlevellogicdesin has some capacitance and resistive measurement equipment maybe we can help to check values of what he measures, but let's see what Scott from Siglent America can put together for him first.

No... I'm not sure of anything I'm going to call and figure out my options. I doubt anything will be free, but if I can use other motherboards in the same chassis with the same screen/controls that opens up a lot more options.

Only if Siglent are happy with sending you other model decals for the front panel too.
It is likely any replacement mobo will need to come from the factory where it will be configured to the correct model.
If warranty applies, rwgast_lowlevellogicdesin will get the same as he already has.

Either way, any replacement mobo will come with a different SN# and a new SN# label for the enclosure.

Edit
Spelling

[rwgast_lowlevellogicdesin]

@tautech, I sent you a PM. I talked to scott today beside trying to trace a signal through the front end with no schematics a 1052 mobo is about my only option.

[tautech]

@tautech, I sent you a PM. I talked to scott today beside trying to trace a signal through the front end with no schematics a 1052 mobo is about my only option.

Got it, been out all day.

I see little reason why if you dismantle the scope, then reconnect all cabling, why you couldn't trace the probe Cal squarewave in the broken channel with the good going one. Be sure to disconnect the Reference (Gnd) of the probe you use and place the sleeve on that covers the reference ring near the point.
This will test your detective work, but before you get ahead of yourself, first identify the active components in the channel input. Datasheets can save your bacon, they often have typical circuit examples and in this case the IC's used are likely scope input specific. This will give you little snapshots of the schematic, most likely enough to give clear points where you can test the signal path. While this might not point to the exact fault, it will narrow the fault to a smaller section, at which point you may be able to find a single faulty component.
Now for any in-circuit passive measurements, grab the pic I posted before of the input section and edit it pointing to any components and I'll measure them on the Mobo I have.
Good luck.

BTW, a very careful inspection of all the solder joints would be what I did first. 

[rwgast_lowlevellogicdesin]

Have you opened up one of these guys before, are you able to physically probe the front end with out removing the whole unit screen and all and then reassembling on the bench?

Second instead of worrying about earth ground problems and screwing with the probes, am I able to just use a cheater plug?

[tautech]

Have you opened up one of these guys before, are you able to physically probe the front end with out removing the whole unit screen and all and then reassembling on the bench?

Second instead of worrying about earth ground problems and screwing with the probes, am I able to just use a cheater plug?

Only CNLs and CMLs but the DL will be very similar. You will likely have to completely dismantle the scope, front panel too.
There is too much risk not to cover the gnd ring on your probe. Just do it please and forget any ideas of isolation, it only gives a false sense of security in this case and is quite unnecessary.