Kpa500 lcd display issue
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The lcd on the kpa 500 shows onlty test pattrrn except when I upgraded the
firmware to version 1.54 from ver 1.38 today during the upgrade the lcu showed Mcu Load like it is suposed to do. When done the unit restarted and the damn test pattern is back all the time. Prior to upgrading thr firmware I suspected the led driver chip U6 PCF8576DT to be at fault since it has the power on reset function which I thought was causing the test pattern, now not so much. Anyway it works 100% otherwise just have to monitor it from the pc port. All other front panel stuff works I suspect the buttons for the menu pwr current and temp work also but I cant tell since the lcd only shows test pattern. Looking for Don or Wayne to comment I put in an email to the mothership yesterday with few details but today much happier I dont have a brick. Wayne Kd5spx ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: Kpa500 lcd display issue
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Wayne;
What are you calling “test pattern”? There is an LCD test in the system, but it is not available normally, and also not a settable configuration. Give me more info and I’ll try to diagnose. 73! Jack, W6FB > On Apr 13, 2020, at 12:30 PM, Wayne Suite <[hidden email]> wrote: > > The lcd on the kpa 500 shows onlty test pattrrn except when I upgraded the > firmware to version 1.54 from ver 1.38 today during the upgrade the lcu > showed Mcu Load like it is suposed to do. When done the unit restarted and > the damn test pattern is back all the time. > > Prior to upgrading thr firmware I suspected the led driver chip U6 > PCF8576DT to be at fault since it has the power on reset function which I > thought was causing the test pattern, now not so much. > > Anyway it works 100% otherwise just have to monitor it from the pc port. > All other front panel stuff works I suspect the buttons for the menu pwr > current and temp work also but I cant tell since the lcd only shows test > pattern. > > Looking for Don or Wayne to comment I put in an email to the mothership > yesterday with few details but today much happier I dont have a brick. > > Wayne > Kd5spx > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Wayne Suite
"All other front panel stuff works I suspect the buttons for the menu pwr
current and temp work also but I cant tell since the lcd only shows test pattern." The KPA500 display will show what looks like a test pattern if menu item LCD ADJ is set to 100. If it used to work you may have accidentally changed the value. Adjusting it with the menu may be difficult if you can't read the display. There may be an undocumented command to set this value or perhaps it can be changed by loading a saved config file. 73, Andy, k3wyc ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: Kpa500 lcd display issue
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There is no serial command to change the LCD ADJ setting. However, you can reset the saved parameters by holding the EDIT button while powering up the KPA.
73, Jack, W6FB > On Apr 13, 2020, at 1:03 PM, Andy Durbin <[hidden email]> wrote: > > "All other front panel stuff works I suspect the buttons for the menu pwr > current and temp work also but I cant tell since the lcd only shows test > pattern." > > The KPA500 display will show what looks like a test pattern if menu item LCD ADJ is set to 100. If it used to work you may have accidentally changed the value. > > Adjusting it with the menu may be difficult if you can't read the display. There may be an undocumented command to set this value or perhaps it can be changed by loading a saved config file. > > 73, > Andy, k3wyc > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by ANDY DURBIN
Given that the "test pattern" may be caused by an extreme LCD contrast setting I'd suggest checking the contrast voltage that is derived from PWM signal VCONTRAST. Contrast voltage is available of "TP2" which is connected to LCD pin 55 (VLCD).
The schematic shows VLCD range is 3 - 6.5 V. I see a good display with LCD ADJ set anywhere between 0 and 30 so I would guess VLCD between 3 V and 4 V would give a readable display. 73, Andy k3wyc ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: Kpa500 lcd display issue
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Andy; Your analysis was correct. Somehow the LCD ADJ value became set to 100. KD5SPX was able to resolve the issue by figuring out the exact keypresses needed to access the menu setting and lower the value.
The range of the value is 0 to 100, with the default being 30. This value sets the duty cycle of a PWM in the microcontroller that is connected to the LCD controller’s Contrast input. At 100 the LCD segments will be shown as grey, but the value should be readable, although it may be difficult to distinguish the exact segments that should be illuminated. There is not much contrast between the grey segments and the black ones. The easiest way to correct this situation is to reset the parameters by holding the EDIT button while powering up the KPA500 using the front panel button. Wayne did find a way without resetting the parameters. My hat’s off to his tenacity in succeeding with that method. 73! Jack, W6FB > On Apr 14, 2020, at 10:25 AM, Andy Durbin <[hidden email]> wrote: > > Given that the "test pattern" may be caused by an extreme LCD contrast setting I'd suggest checking the contrast voltage that is derived from PWM signal VCONTRAST. Contrast voltage is available of "TP2" which is connected to LCD pin 55 (VLCD). > > The schematic shows VLCD range is 3 - 6.5 V. I see a good display with LCD ADJ set anywhere between 0 and 30 so I would guess VLCD between 3 V and 4 V would give a readable display. > > 73, > Andy k3wyc > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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"At 100 the LCD segments will be shown as grey, but the value should be readable, although it may be difficult to distinguish the exact segments that should be illuminated. There is not much contrast between the grey segments and the black ones."
While I was experimenting with contrast settings I found that the KPA500 display is very sensitive to viewing angle. My KPA500 is mounted low and right of my normal eye position. From that viewing angle 100 gives all bars on and no possibility of reading the actual displayed value. However, I found that by getting down on the floor so I could view the display from below, the displayed value could easily be read. So, next time this happens to someone, view the display at an extreme angle from below and selection of the appropriate menu item should be easy. I always enjoy learning from other people's problems. So much better than learning from my own. 73, Andy, k3wyc ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Elecraft mailing list
Hi Jack,
Just for future reference - Does loading a previously saved config file restore all settings that were reset by powering up with EDIT pressed? Thanks and 73, Andy, k3wyc ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: Kpa500 lcd display issue
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I believe the answer to be yes. It would overwrite the parameters, so any problems in the saved configuration would be restored. Of course, so would all the valid parameters.
73! Jack, W6FB > On Apr 14, 2020, at 4:40 PM, Andy Durbin <[hidden email]> wrote: > > Hi Jack, > > Just for future reference - Does loading a previously saved config file restore all settings that were reset by powering up with EDIT pressed? > > Thanks and 73, > Andy, k3wyc ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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