[Need Repair help] [Teardown Photos] Data Check 1880 Scan/Scope  - Page 1
Forum section: electronics / testgear

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: December 25, 2015, 06:33:55 am
content: Teardown!!http://imgur.com/a/4rqwEFor those new here, please refer to this post:https://www.eevblog.com/forum/testgear/(help-please)-data-check-1880-scanscope/msg830679/#msg830679So I just got a Data Check 1880 Scan/Scope for Christmas. It seems to more or less be functional, although it has a couple little derps. But the issue is that I cannot seem to find a service manual anywhere for it. I also feel a little bit bad about this, because the main function of the device is its digital data display capabilities, rather than its analog functionality. It does not seem to be a very fancy analog scope, which is what I wanted.Returning the scope and buying a different one is not an option, so I gotta make do with what I have. I have a couple questions:1. What functions am I missing out on with this scope compared to a basic analog scope?2. Can I use any external devices to make up for those missing features? One thing I noticed was a lack of AC/DC coupling...3. Does anyone have a service manual for this thing?Here are some images:If you are wondering what was with the crappy wires and stuff on the back of it, that was just me dicking around with my phone on the analog input. I do not have any probes yet.So any suggestions/opinions/comments on this scope?

author: alsetalokin4017
author_rank: Super Contributor
timestamp: December 25, 2015, 07:20:20 am
content: Quote from: iamdarkyoshi on December 25, 2015, 06:33:55 amIt's certainly not a very fancy analog scope.... it's not even a basic analog scope. It's a specialized display module made for a specific purpose.QuoteThat is really a shame. Are you quite sure about that? No way out of this deal?QuoteAll of them. For example, your full-screen display will only cover 100kHz, according to the knob on top right. This corresponds to 100 microseconds per horizontal division, if I did the math right. Even a basic Tek 2213a or similar low-end analog scope goes down to 0.05 microseconds per division and has a 10x magnifier on top of that. There doesn't seem to be any way to adjust the trigger level, or do x-y mode, or trace addition/subtraction (inversion). Vertically you only get 10V/div max, with no choice about probe attenuation. There is no probe calibrator output for adjusting probe compensation. No bandwidth limit.... since its bw is probably so low it's not worth mentioning. No delayed timebase. No add/alt/chop channel trace modes. No variable trigger holdoff, no single sweep mode. Etc.QuoteWell... you could use an .... oscilloscope..............QuoteNo. Google has not even heard of Data Check Corporation.(images removed)QuoteI'm wondering if you actually got it to display any kind of trace at all.QuoteSure. Leave it in the alley, maybe someone will take it away and you won't have to pay a hazardous waste disposal fee.Then save your pennies and buy a Tek 2213a or similar, actual real oscilloscope.(Of course I could be wrong, and you could be holding something like an original Apple Lisa or something, that's worth thousands of dollars to a collector.)

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: December 25, 2015, 07:40:43 am
content: Quote from: alsetalokin4017 on December 25, 2015, 07:20:20 amWell thanks for the response. I was able to get waveforms on the screen in scope mode, the output on my phone fed directly into the BNC on the back shows a trace on the screen. Pretty decent trace as well. In fact, every single BNC (aside from the external trigger) on the back can be switched into the scope. I would have an image of the scope displaying a waveform, but my phone's signal generator shuts off when I switch apps. The low bandwith certainly explains why I have nearly 30 switchable inputs, no way in heck that mechanical switch would cleanly do higher frequencies...

author: tautech
author_rank: Super Contributor
timestamp: December 25, 2015, 08:03:49 am
content: Quote from: iamdarkyoshi on December 25, 2015, 07:40:43 am30 Ch logic analyzer ?

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: December 25, 2015, 08:08:16 am
content: Quote from: tautech on December 25, 2015, 08:03:49 amBasically what it is, with the ability to see the analog waveform. But of course, one at a time. The scope mode can be turned off and switched to data display, where it is basically a logic analyzer for 14ch, or the other 14ch with the a/b switch. Then the last two BNCs are the external trigger and the aux. input, which is basically scope-only

author: tautech
author_rank: Super Contributor
timestamp: December 25, 2015, 08:16:37 am
content: HmmTime to take the covers off and see if there are further clues inside to help identify it.Stickers/labeling on the outside might be just a re-brand of a known manufacturer.Look for clues on the PCB silkscreen to its origin.Teardown time.

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: December 25, 2015, 08:19:57 am
content: Quote from: tautech on December 25, 2015, 08:16:37 amI have already peeked inside only like 20 times now. Tomorrow might be a full teardown. I do remember seeing a brand name of some sort on the PCBs. Like every damn voltage rail is labled, but not a single trimpot

author: nidlaX
author_rank: Frequent Contributor
timestamp: December 25, 2015, 09:48:03 am
content: Wow, take a look at this:https://web.archive.org/web/20150210010543/http://datacheck.com/index.htmlDoes that logo look familiar? It seems like you may have just missed them, the company web page is no longer in service! An interesting company with a very long history, starting before the 70s from audio and tape recorder instrumentation, then various mergers/acquisitions/rebrands including a period under 3M, then its presence in San Diego until the mid 90s, and finally its last years as a maker of video displays and related equipment. (Source) If you look athttps://web.archive.org/web/20020804142329/http://www.datacheck.com/, you can see the original logo from your Scan/Scope still in use. I recommend tracking down some people associated with the company and asking them for a history lesson.

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: December 25, 2015, 03:06:06 pm
content: Quote from: nidlaX on December 25, 2015, 09:48:03 amWow, that is a very interesting find! Thanks!

author: radhaz
author_rank: Regular Contributor
timestamp: December 25, 2015, 07:52:49 pm
content: It comes from an interesting place:https://www.google.com/search?q=fleaswtracenpac&ie=utf-8&oe=utf-8

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: December 26, 2015, 03:03:06 am
content: Well, for those interested, here is the "device" displaying a trace.for those interested even more, it is connected to my wireless QI charger's coil. Probe set to x10 attenuation.Seems like pretty much the limit on the scope in terms of frequency...Edit: Channel 7's digital functions seem to be broken...

author: alsetalokin4017
author_rank: Super Contributor
timestamp: December 26, 2015, 06:09:52 pm
content: Well, color me amazed.Now, what is the frequency of that signal? What is the p-p voltage? What is the DC offset, if any? What are those little ghosty things on the rising and falling edges? Where exactly on the waveform is it triggering? Can you display another trace simultaneously?

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: December 26, 2015, 07:57:26 pm
content: Quote from: alsetalokin4017 on December 26, 2015, 06:09:52 pm~50khz~17V p-p (I had no idea this charger managed to get such a high voltage on the coil, it is not a cheapie from fleabay)No DC offset (I figured out how to DC couple on the scope, EVERY BNC has a switch on the back for AC/DC coupling)It seems to be little blips from either my tablet or my charger communicating to each other, they happen like every second or so, and my phone's slow shutter and the phosphors on the screen are why you see themNot sure, it seems to be where the signal reaches 0V, and then a little bit is cut off at the start of the wavefom...NoI calibrated the scope with the probe set to X1 (no need for X10 to be honest, X1 still has far higher bandwidth than the "scope") I adjusted the V/Div using a multimeter and battery, and I adjusted the scanning frequency using a 1khz sine wave.Here is the scope displaying a 1khz sine wave, generated by my tablet:As you can see, it seems to start the trigger at the start of the waveform's 0V point, and cut off the first part...Anyway, do you guys want to see a teardown? I took it apart yesterday and I was really quite surprised... Honestly I really do not need to ask the question, I am sure the overwhelming response will be "Yes"Photos are being uploaded...

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: December 26, 2015, 08:10:16 pm
content: 32 uncompressed 8 megapixel Jpeg images. This might take a while.Edit: Done!http://imgur.com/a/4rqwE

author: tautech
author_rank: Super Contributor
timestamp: December 26, 2015, 10:54:38 pm
content: Quote from: iamdarkyoshi on December 26, 2015, 07:57:26 pmUse of a 10x probe will allow the display of waveforms beyond the vertical attenuation range of the input stages for higher voltages.Most scopes have a Cal square wave for probe adjustment and you'd have to improvise to be sure a correct waveform reproduction is displayed. Normally the Cal is just a bipolar oscillator ~5v and 1 KHz, you could probably make one with a 4093 that would work well.QuoteCRO's have a horizontal position pot to adjust the waveform to fit the graticules and internal adjustments to ensure the trace fills the graticules, for just a hack unit I'm sure you can live without these.Been an interesting find and thanks for sharing.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: December 26, 2015, 11:16:53 pm
content: What a great source of spare parts!

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: December 26, 2015, 11:20:13 pm
content: Does anyone have any ideas as to how to fix channel 7's digital fuctions? The data readout on the screen as well as the high/low LEDs always reads high. Feeding a signal into the back of 7a or 7b shows the signal in scope mode, but nothing in digital mode. Both 7a and 7b show as high in digital mode.

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: December 27, 2015, 04:12:34 am
content: This channel 7 fault has been bothering me all day, I cannot seem to figure out the fault! I am comfortable taking the scope now, as I have done it many times over at this point. Making sure caps and CRT are both discharged every time I dink with itIf I can fix channrl 7, I might be able to sell it as "Used" rather than "For parts or not working" as every single BNC displays a perfect trace in scope mode, but in digital signal mode, channel 7 is fubar.

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: December 27, 2015, 06:03:58 am
content: Well, a bit of an update. I have been probing around on the digital board to figure out where each signal goes. It seems that the op amp for channel 7 has nearly 8v on pin 13 (vcc) while every other one has like 4.2 or so. The output is also pegged at like 15 volts, oddly. Maybe I am doing my readings stupid or something, but this chips output does not changr, but the rest of them do whrn fed a signal, so its a place to start. The op amps are CA3030 chips. Man, do those damn things run hot, same with the comparators.

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: December 27, 2015, 11:42:41 pm
content: So I have now narrowed down the issue with digital channel 7. I have had some weird readings from the CA3030 op amp that channel 7 uses. With nothing connected to the inputs, here were the voltages I got on each pin of a working channel, and then channel 7, the nonworking channel:The scope's digital function has 28 inputs, only 14 of which can be used at a time, 1a-14a or 1b-14b. The front A/B switch must switch these channels in some way. I have not located where this is done. Anyway, there are 14 digital sections in this thing, all of the odd numbered channels plus channel 14 is done on the bottom board, and the rest of them are done on the top board:This is the channel that has gone kaput:Here is the same photo without the paper:Here is the back of this board, the fourth section from the bottom is the problem channel:Feeding a 1hz 5v square wave from a 555 timer into the digital channel 7, I was able to see some pulsing activity on some of the pins of this op amp, but the output is pegged high with no change. Doing the same on the other channels, I could see activity on both the inputs and output of the op amp. So I think this section is where the fault lies. It MIGHT be somewhere in the circuit that switches between A and B channels though.I have done some other playing with the scope's adjustment trimpots on the outside.The 28 trimpots underneath the display let you adjust the voltage gain for each of the digital channels. I adjusted each of these (excluding channels 7a and 7b) to make it so 5V peaks the bar graph to the top of the screen.The high/low trimpots on the high/low LED display are the voltage thresholds for what voltage is considered high, and what voltage is considered low.Anything you guys want me to measure the voltages on to try to track down the issue? Thanks for the help

author: GoldSrc
author_rank: Contributor
timestamp: December 28, 2015, 02:40:07 am
content: That sure is an interesting device, I've never seen such thing.Have you had any luck trying to find the service manual?, from the little research I've done I can't find much.

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: December 28, 2015, 04:31:38 am
content: Quote from: GoldSrc on December 28, 2015, 02:40:07 amGoogle literally has not heard of the manufacturer. They can be found on waybackmachine as mentioned previously. This model however, I can find one on ebay and one mention some guy's site (on google) and thats it. No service manual.

author: GoldSrc
author_rank: Contributor
timestamp: December 29, 2015, 02:37:06 am
content: Quote from: iamdarkyoshi on December 28, 2015, 04:31:38 amHave you tried to send an email to the email address that's in the waybackmachine?They could be dead but I don't think you lose anything trying.

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: December 29, 2015, 02:46:06 am
content: Quote from: GoldSrc on December 29, 2015, 02:37:06 amIt is worth a shot, I guess. Chances seem pretty slim though