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  • #1

    JSD100 blank display

    Hi!
    I've opened a case on QSC support portal, but... I've an USL JSD100 is in this condition:
    - when powered up with normal power all tensions LEDs are ok, the display is backlighted but does not show any text.
    - if I do a restore factory firmware procedure, the reset starts, button leds flash correctly, then the mute stays active, but nothing appears on the display
    - in bypass mode buttons are correctly responding, but nothing on display
    - the unit is not reacheable via USB nor ethernet
    Has anyone experienced the same situation (with a positive resolution)?
    Tags: None
  • #2
    The fact that it also doesn't respond to USB or Ethernet either is probably a sign of some deeper trouble with the micro-controller inside.

    I guess you've tried reaching the unit on its default IP address with a correct subnet mask?

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    • #3
      I've used the Ethernet Discoverer tool from Qsc/USL

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      • #4
        The blank display on a JSD-100 is generally due to a poor connection between the main board header and the ribbon cable driving the front panel. It can often be fixed by unplugging the cable, then plugging it back in. For a while, the ribbon cable connectors did not have gold plaiting causing this issue. The factory firmware restore SHOULD work, but if it somehow got corrupted, the unit probably has to be returned. We used to send out preloaded ICD-2 units in a "Programmer to go" mode that would allow full reprogramming of the microcontroller. We sent those overseas where returning a unit would be real expensive. I don't know if that's still done. Ideally reseating the cable will fix it!

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        • #5
          Oh, one more thing... If you can plug a terminal into the RS232 port, it outputs a bunch of letters as the software starts up. As I recall, it's at 38.4 kbps, 8N1. From the letters sent, you can tell how far it is getting in the boot process.

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          • #6
            The serial connection shows only this character: â–’
            It appears after the second blink of the LED1 on the main board.
            I've already reseated the flat cable but with no success and I've used contact cleaner, but I'll try again later.
            As I'm in Italy, the reprogramming without shipping the unit would be great, but for now the case is still "New"...

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            • #7
              Maybe Harold remembers the baud-rate wrong, trying somethng common as 9600, 19200 and 115200 might be worth a try. Otherwise, I guess the thing already gives up in a very early stage in its boot process.

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              • #8
                I did a mistake setting Putty... Harold was right
                At 38400:
                Code:
                ABCDEFG
WDT timeout, PC=0x9d00e114, ProcessNum=0
aaaaABCDEFG
WDT timeout, PC= 0x9d00e270, ProcessNum=0



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                • #9
                  Maybe Harold can dig something from his memory or deep knowledge what that entails.

                  The WDT timeout thing is something I've seen before. The watchdog feature is something like a deadmans switch in a train, you need to trigger it once in every interval, or otherwise it assumes the program has crashed and it resets the microcontroller. So, it is clearly stuck on something at boot that hangs the system.

                  The Program Counter (PC) register is different between each loop though, so it seems to be stuck in some kind of loop it can't get out of...

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                  • #10
                    It's getting pretty far in the boot process. If the application were corrupt, it would only do A or B. I have to go help someone get a model 28 Teletype on the air, but I'll check later and tell you how far it is getting in boot up and what a possible issue is. I'm glad it's doing something!
                    • Likes 1

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                    • #11
                      Sorry it took so long to look this up. We DID get my friend's Teletype model 28 on the air today!

                      In the latest version of the firmware, the letter G is printed system puts default network settings in RAM. They will be overwritten later with values read from flash. The system then tries to initialize the Ethernet controller. It appears this is failing. There is a possibility that the letters moved around some in various versions of code, but, in any case, I think it is a hardware failure that will require factory service. It's not just corrupt program memory.

                      The Ethernet controller, the front panel, and the DSPs are all on a parallel bus. It could be something else on this bus that's killing it. For the fun of it, it would be interesting to unplug the front panel and then see if the alphabet on the RS232 port gets farther. If the entire system comes up, it would be a bad front panel killing the bus.

                      Let me know how it goes, and good luck!

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                      • #12
                        Originally posted by Harold Hallikainen View Post
                        The Ethernet controller, the front panel, and the DSPs are all on a parallel bus. It could be something else on this bus that's killing it. For the fun of it, it would be interesting to unplug the front panel and then see if the alphabet on the RS232 port gets farther. If the entire system comes up, it would be a bad front panel killing the bus.
                        With front panel disconnected the alphabet remains
                        Code:
                        ABCDEFG
                        I see that most times LEDs D23 and D24 (that I think are related to DSP2) don't blink at all, but even when they link, the alphabet does not change.

                        We DID get my friend's Teletype model 28 on the air today!
                        Is it receiving interesting messages now?

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                        • #13
                          Even more interesting, what did you manage to hook it up to?

                          Sorry, didn't want to hijack your topic Elia, but I'm always at least mildly intrigued by antique "computing" hardware.

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                          • #14
                            Sorry I could not offer more of a solution on the JSD-100. Yesterday we got my friend's Teletype model 28 connected to a HAL-6000 terminal unit driving a Yaesu HF transceiver. At home, I use a Teletype model 15 printer with model 14 punched tape equipment connected to a Flesher TU-170 terminal unit driving an SEA-245 transceiver.

                            https://w6iwi.org/rtty/
                            https://w6iwi.org/

                            Amazing mechanical machines. Perhaps like film projectors!
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                            • #15
                              Ah, so you're doing some real amateur-RTTY with that gear.
                              Maybe I can try firing up my old BBS, together with Fidonet to E-mail gateway and try to couple it to RTTY? :P

                              I've never seen a HAL ST-6000 in real life, but is 't that thing with the evil looking scope in the center, looking like an eye?

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