Products > Test Equipment
Tektronix THS7xxx Scope Hack/Teardown/Discussion - FW 1.16 found
walter.aranda:
my friend, I just noticed that I have the same problem (virtualbox Win7 & FTDI cable) as you when trying to communicate with baud rates higher than 9600. I tested with 19200 and 38400, and indeed, as soon as I change this setting on the scope, the hardware communication stops, and I even need to disconnect the cable to restore communication. I saw in the programming manual, Table 1-2, that it is recommended to leave the default configuration (I'll send an image); however, I don't understand why the options to increase the baud rate exist if this is not possible. Could it be due to some limitation from not using a pure serial cable? Could someone show if this problem occurs with an RS232-RJ45 cable for a PC's serial port? In any case, I can communicate at 9600, so I'm not too concerned about the transfer speed at the moment. Finally, I've noticed that I'm unable to do data logging from the scope to the PC—can you? Could you show me how to do it? If you wish, you can contact me privately. Best regards!
mrprecision:
It seems that connection do SignalAnalyzer works. The free version is limited to 512 samples, so you need a licence key to use it.
jal1234:
--- Quote from: walter.aranda on September 03, 2024, 07:12:11 pm ---my friend, I just noticed that I have the same problem (virtualbox Win7 & FTDI cable) as you when trying to communicate with baud rates higher than 9600. I tested with 19200 and 38400, and indeed, as soon as I change this setting on the scope, the hardware communication stops, and I even need to disconnect the cable to restore communication. I saw in the programming manual, Table 1-2, that it is recommended to leave the default configuration (I'll send an image); however, I don't understand why the options to increase the baud rate exist if this is not possible. Could it be due to some limitation from not using a pure serial cable? Could someone show if this problem occurs with an RS232-RJ45 cable for a PC's serial port? In any case, I can communicate at 9600, so I'm not too concerned about the transfer speed at the moment. Finally, I've noticed that I'm unable to do data logging from the scope to the PC—can you? Could you show me how to do it? If you wish, you can contact me privately. Best regards!
--- End quote ---
What version of Wavestar are you using? There was no option to change the baud rate in 3.0 that there was in earlier versions. Maybe the fact that Wavestar can't seem to communicate at that speed caused then to delete that option.
I haven't done much with Wavestar yet. I'll look and see what I can do when I get a chance.
Oh, and I'm using a serial cable with my Panasonic CF-19. No USB in the mix.
jal1234:
--- Quote from: mrprecision on September 03, 2024, 07:40:34 pm ---It seems that connection do SignalAnalyzer works. The free version is limited to 512 samples, so you need a licence key to use it.
--- End quote ---
Oh, I see. The documentation to use SignalAnalyzer with the THS7xx is basically non-existant. I wish there was a trial period to try it before the limits kicked in. As it is, I'm hesitant to buy a license without making sure it actually works.
I've managed to get a couple of screens by fluke, I guess, a couple of times. Non-repeatable, and nothing useful was on screen.
HAHSM:
Hello all, new member, my finding this discussion motivated me to join eevblog!
...I just recently picked up a THS720P as Parts/Not Working from ebay. Just the unit, no accessories or probes or anything. It seems to actually pretty much work so that's great, yes?!, have wanted one for a long time...
It has the dc offset issue that others also have experienced, but not as great as some others have reported. Doing the cal often fixes that, we'll see if it fixes mine. I'm in the process of making a precision voltage reference and square wave generator so I can do the scope section cal myself.
The battery of course is dead - an original Tek NiCad from 1996...and even after attempting to charge for 24 hours it only showed 0.05vdc, dead. I made a 12v power cord and it powers up and self check & the simple cal functions all pass. Display is good, I get signals on both channels. DMM works fine. Seems I got lucky with this one!
I have parts on the way to make my own (2) NiMH battery packs from Amazon Basics 5000mah C's - I have a battery spot welder and nickel strips and PVC shrink wrap so should be easy to duplicate the OEM one...
So I've started digging into this scope a bit and have noticed a curious thing I haven't seen posted elsewhere...
But first, it's got 1.08 fw, would love to load 1.16 on it. I tend to think that 1.16 improves the cal function and is less prone to the dc offset issue. No way does my skill set include R&R'ing the necessary chip, but does include designing parts (in FreeCAD) and printing 3D parts. Seems like I could make the plug adapter that plugs into the main board similar to the factory setup, but don't know how to operate the programmer to actually upload the firmware. Last time I programmed IC's it was EEPROMS and EPROMS, remember those? I have read all the related posts in this thread so know the extents folks have gone to - to try to upload the firmware. Perhaps I could team up with others to make a standard cable setup for firmware updates, if folks are still interested, I sure am.
OK - curious thing - the Service Manual says to remove the cal jumper to enable the calibration function, I did this (not the cal yet though) and sure enough saw the cal functions in the menus afterwards. Curious thing though is that it's not a 2 pin header that the jumper goes on but a 3 pin header with 2 possible jumper positions - two leftmost pins or the two rightmost pins. Originally the jumper was on the two leftmost pins for normal functionality. The Service Manual doesn't point out to make sure to put the jumper back on the two leftmost pins, nor does it say what happens if the jumper is placed on the two rightmost pins. So of course I had to try it. Bizarre! On powerup it immediately goes into some loop that appears to be strange screen diagnostics and I couldn't find a way to exit the loop - all keys and even the power button was ignored. So I pulled the 12v supply, thinking this would cause immediate power off since the battery is flat dead -NOT- the scope kept running the strange screen stuff with no power source - off of what power source? I wanted to put a quick end to this since it wasn't clear what was going on, and I want this scope to survive, so I popped the battery pack out - screen stuff still running - and immediate power off. Turns out putting the jumper in the rightmost position made the scope revive and start charging the battery again (in addition to whatever was going on with the screen, and who knows what else in the background. So the scope runs now off the 30 year old previously flat dead battery...and with the jumper back over the leftmost pins the scope operates normally again.
Anyone else experience this? I haven't seen any other posts about the 3 pin header for the cal jumper, anyone else know about this and what the rightmost position is intended for? I didn't see anything in the Service Manual (haven't checked the schematics yet).
Also I'm curious how others have made their own cal circuits to do a diy calibration (for those of us who don't have a nice bench full of signal generators and precision power supplies and scope calibrators and such.
I do have several trusted Fluke DMM's and an older reasonably accurate 60mhz analog scope so I should be able to hack together some reasonably capable diy cal equipment.
For the precision voltage references I'll be using a REF10EZ 10 volt precision reference, then simple resistor voltage dividers for the 3 needed +-voltages, adjusted via precision trimmer resistors.
For the square wave generator I thought I'd try a simple rc oscillator into a 74HC14 hex inverter with Tr and Tf avg of 7ns - so well under the 20ns rise time spec'd in the Service Manual. I'll do my best to verify accuracy of these before using them to do the cal.
I look forward to replies 😎
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