Pretty sure I have them now I'll make sure I update stock On Fri, Jul 4, 2025, 7:08 AM Stephen Adolph <[email protected]> wrote:
> > https://www.arcadeshopper.com/wp/store/#!/Crystal-Oscillator-32-768-KHz-32-768KHZ-32-768K-Hz-Cylinder-3x8mm-quartz/p/237308514 > > arcade shopper has the crystals from time to time, or you can get a bag of > them on ebay pretty easily. > > > > On Fri, Jul 4, 2025 at 9:57 AM Stephen Adolph <[email protected]> > wrote: > >> https://digilander.libero.it/rar2k/TRS80/Images/M100-Pcb.gif >> >> Do you have a scope? You could check that the timer interrupt input >> RST7.5 is toggling every 4msec. >> >> Timer interrupt TP is generated at M18, which is the RTC chip. It is >> fed from 32.768kHz crystal X1. >> >> Not saying for sure this is the problem but it looks similar to other >> machines I have fixed where that crystal was dead. >> >> >> >> On Fri, Jul 4, 2025 at 9:06 AM Thomas Morehouse <[email protected]> >> wrote: >> >>> Thanks Steve. Can someone point me to appropriate schematics or >>> diagrams, finding a replacement crystal, and how to perform the surgery? >>> TM >>> >>> >>> On Fri, Jul 4, 2025 at 9:01 AM Stephen Adolph <[email protected]> >>> wrote: >>> >>>> it is suffering from excessive interrupt-itis. >>>> >>>> On Fri, Jul 4, 2025 at 8:58 AM Stephen Adolph <[email protected]> >>>> wrote: >>>> >>>>> looks to me like the 32768 hz crystal is dead. >>>>> >>>>> On Fri, Jul 4, 2025 at 8:56 AM Thomas Morehouse <[email protected]> >>>>> wrote: >>>>> >>>>>> Friday update: >>>>>> >>>>>> Batteries replaced with fresh AA alkalines yesterday (Thursday). >>>>>> Left powered off overnight to recharge backup battery. Powered up this >>>>>> morning, but no change. See attached screen photo. >>>>>> >>>>>> The screen clock seems to be working, but date never changes from >>>>>> 1/1/1900. >>>>>> Top four lines of screen appear normal, but below that, definitely >>>>>> not normal. >>>>>> >>>>>> The "center" screen line consists of constantly changing characters. >>>>>> Lowest screen line appears to be reiterations of "Bytes free" - without >>>>>> the >>>>>> "Byt". >>>>>> >>>>>> None of the keyboard keys have any effect; when "cursor" is over >>>>>> BASIC, hitting Enter changes nothing - screen remains unchanged. >>>>>> >>>>>> I've done several Cold Starts (CTRL+Pause/Break+Reset) and >>>>>> (CTRL+Pause/Break+Power switch), but no apparent change. >>>>>> >>>>>> Note: when I do a Power On, the screen quickly shows the correct >>>>>> original default M100 screen, then immediately changes to the garbled >>>>>> screen. >>>>>> >>>>>> Onward through the fog! >>>>>> Thanks. >>>>>> Tom M. >>>>>> >>>>>
