Yep. CUPL and ABEL (from Data I/O). On Sunday, June 23, 2024 at 12:34:45 PM UTC-5 gregebert wrote:
> Weird indeed, and needs to be investigated. Have you done a few resets and > power-cycles just to be sure ? > > Any chance you are using revision-control with your source-code ? > Sometimes there are other changes you made, but forgot. I know it sounds > stupid, but I've done it many times myself and the evidence was right > there, thanks to git (or whatever source-control you use). > > Years ago, I have also seen bugs in CAD tools. Anyone here remember CUPL ? > It was a tool used for generating PLA code from logic equations. Sometimes > as you got close to filling-up the device, the tool would report you ran > out of logic elements. But, if you were lucky, simply re-arranging lines of > code got it to fit-in. It seems unlikely that Teensy would have this > problem, but you never know. > > On Sunday, June 23, 2024 at 10:19:05 AM UTC-7 Max DN wrote: > >> So, it seems it is now working as expected, although I'm not counting my >> chickens yet. In the SPI routine from the Teensy to the DAC, I changed the >> gain for the DAC from two to one, loaded the code, edited the code back to >> a gain of two in the DAC, loaded it again and voila'. Odd! >> >> It's working as expected. Although I don't understand why! >> >> Il giorno domenica 23 giugno 2024 alle 02:46:09 UTC+1 gregebert ha >> scritto: >> >>> So another possibility is that one of the amplifiers is clipping, >>> usually because the input signals are trying to drive the output beyond the >>> supply rails. BTW, most op-amps are not rail-to-rail, but they can get >>> pretty close. It will show up quickly on a scope. >>> >>> On Saturday, June 22, 2024 at 3:35:15 PM UTC-7 Dekatron42 wrote: >>> >>>> So what happens if you put this Teensy in the other working board, does >>>> the error follow the Teensy? >>>> >>>> If so, have you tried to reprogram the Teensy or even erase it to set >>>> it to its original setup condition? >>>> >>>> /Martin >>>> >>>> On Saturday 22 June 2024 at 22:48:49 UTC+2 Max DN wrote: >>>> >>>>> @Martin, if I try to bypass the DAC using POTs for NEG5 and POS5 it >>>>> all seems fine (the dot goes across the whole X axis and Y axis). >>>>> @gregebert, no Z-axis. >>>>> >>>>> I am probing X and Y just out of the DAC and not connected to anything >>>>> else. I can see the image on the oscilloscope as a full round circle, but >>>>> as I try to center it to what would be the center of the CRT then thr >>>>> circle flatlines. >>>>> >>>>> It feels as though past a certain point on the vertical axis, the dots >>>>> are just collapsing into the same line and cannot go past (on one end of >>>>> the Y vertical axis, X axis is fine). >>>>> >>>>> Very odd as I have already used same code and same pcb for another >>>>> scope clock. After 10 hours on it today, I'm going to let go until I have >>>>> any other ideas. I have tried replacing the processor, the DAC (3 times), >>>>> checked all resistors and bypass caps and triple checked all soldering >>>>> points. Maybe it's time to bin this pcb, but I do like a challenge! >>>>> >>>>> >>>>> Il giorno sabato 22 giugno 2024 alle 16:38:19 UTC+1 gregebert ha >>>>> scritto: >>>>> >>>>>> Is there a Z-axis ??? That would be my first suspect; if the trace is >>>>>> still visible, then the appropriate grid needs to be driven a bit more >>>>>> negative. >>>>>> >>>>>> If the CRT uses rapid movement for dark (technically dim) regions, >>>>>> and slower movement for bright regions, then my best guess is some kind >>>>>> of >>>>>> software tweak would be needed to get the beam to move faster, or off >>>>>> the >>>>>> phosphor-coated area (or both). >>>>>> >>>>>> On Saturday, June 22, 2024 at 3:49:04 AM UTC-7 Dekatron42 wrote: >>>>>> >>>>>>> Can you remove the processor and feed the amplifiers directly from a >>>>>>> potentiometer connected to NEG5 and POS5 and see how the dot moves on >>>>>>> the >>>>>>> screen? You need one potentiometer for X & Y so that the dot will >>>>>>> appear on >>>>>>> screen. This way you will test out the amplifier chains without the DAC >>>>>>> involved. >>>>>>> >>>>>>> /Martin >>>>>>> >>>>>>> On Saturday 22 June 2024 at 12:10:54 UTC+2 Max DN wrote: >>>>>>> >>>>>>>> Martin, that's what I am thinking... however I don't think it's the >>>>>>>> amplifier chain as I get the same issue if I just display X and Y >>>>>>>> signals >>>>>>>> straight out of the DAC on the oscilloscope. That brings it down to a >>>>>>>> few >>>>>>>> components only: 2 potentiometers for centerting X and Y, their two >>>>>>>> bypass >>>>>>>> capacitors, the DAC and its 1 bypass capacitors, the +3.3V Linear >>>>>>>> regulator, the +5V supply to the DAC. I'm going to try and replace >>>>>>>> everything once more by one by one... Not the smartest way of doing it >>>>>>>> but >>>>>>>> let's see what it brings... >>>>>>>> >>>>>>>> Il giorno sabato 22 giugno 2024 alle 11:01:12 UTC+1 Dekatron42 ha >>>>>>>> scritto: >>>>>>>> >>>>>>>>> Could it be the that any of the power lines sags as the signal >>>>>>>>> tries to increase to the right (in the picture right where the line >>>>>>>>> is) or >>>>>>>>> that any of the resistors in the amplifier chain has an incorrect >>>>>>>>> value? >>>>>>>>> >>>>>>>>> /Martin >>>>>>>>> >>>>>>>>> On Saturday 22 June 2024 at 11:32:21 UTC+2 Max DN wrote: >>>>>>>>> >>>>>>>>>> Tried to replace a few more parts, including potentiometers for >>>>>>>>>> Focus and Intensity, made no difference. So, back to basics: using >>>>>>>>>> an >>>>>>>>>> oscilloscope I see that the X and Y signals straight out of the DAC >>>>>>>>>> look >>>>>>>>>> exactly the same as in the picture I had attached. Maybe a faulty >>>>>>>>>> DAC? >>>>>>>>>> Tried to replace the DAC twice with new ones and made no difference. >>>>>>>>>> Looks >>>>>>>>>> like I'm hitting some sort of physical limits... More debugging to >>>>>>>>>> do... >>>>>>>>>> >>>>>>>>>> Il giorno venerdì 21 giugno 2024 alle 18:31:51 UTC+1 Max DN ha >>>>>>>>>> scritto: >>>>>>>>>> >>>>>>>>>>> Hello, >>>>>>>>>>> >>>>>>>>>>> I'm building a scope clock, same board as another one I built >>>>>>>>>>> before with no issues (after some help I got on this group, thank >>>>>>>>>>> you!) and >>>>>>>>>>> I'm getting a flat line on the display. >>>>>>>>>>> >>>>>>>>>>> I have tried replacing the CRT, the DAC, the Op Amps and the >>>>>>>>>>> MPSW42 deflection amplifiers but made no difference. CRT is 3RP1A. >>>>>>>>>>> Code and >>>>>>>>>>> circuitry have been fully tested on another working board. >>>>>>>>>>> >>>>>>>>>>> I do recall having a similar issue before with a DH3/91 CRT and >>>>>>>>>>> I seem to recall that I just needed to adjust the pot for >>>>>>>>>>> Astigmatism that >>>>>>>>>>> controls the voltage on A2. Schematics as in here: >>>>>>>>>>> http://www.cathodecorner.com/sctv/sctv-schem-2.png >>>>>>>>>>> >>>>>>>>>>> I'm a bit at a loss here, although I'm sure it's something >>>>>>>>>>> simple that I'm missing. >>>>>>>>>>> >>>>>>>>>>> Pic attached. >>>>>>>>>>> >>>>>>>>>>> Any suggestions welcome, >>>>>>>>>>> >>>>>>>>>>> Max >>>>>>>>>>> >>>>>>>>>> -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. 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