I have got an old Gardtec GT595 alarm which has got a faulty keypad with a failed LCD screen. This was apparently a very common problem with these and many people have had to replace the whole alarm because of this problem. Somebody claims to be able to repair the keypads by replacing the screen and I have tried it myself by replacing the LCD with a commonly available HD44780 1602 16x2 Serial LCD screen but it is not working. I am sure it is a problem with a driver or simular which is not allowing the screen to talk to the rest of the electronics. Does anyone know what this original screen was and what replacement screen and driver it might need? Working on 16x2 screens is new to me.
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Dunno what he does to it, but for some reason after the repair the GTAG does no longer function. Wonder why?
The 4 wire keypad LCD display can be repaired but the GTAG Will no longer function
The 6 wire keypad LCD display can be repaired but the GTAG Will no longer function.
Repair models include 595 600 490 490x and 800 series -
the display is a regular parallel interface display,
you can get them in lots of colours but also different payouts.
so if you buy one on aliexpress or wherever, make sure it's got the same hole spacings for the screws and the connector is the same.
yours has the connector as a single row top-left, you can also get the with the connector on the bottom or as 2 rows on the side.
but electrically theyare all the same.
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maybe show us what it connects with?
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Here are some more photos of the keypad. It is very hard to find a reasonably priced working keypad for these alarms. It is put me off buying another Risco alarm. I am not very happy that the engineer locked their own code into it as well so would install one myself next time.
When I tried replacing the screen on this one, I disturbed a very small bit of glue holding the G-Tag wiring and the G-Tag now no longer works so it is something to do with the effect that it has on the coil.
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check the display is getting 5v
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What controller ic chip does it have on the main board
It has been my experience that when you have LCD screens controllers are not the same even if they are the same model number you have the LCD command loaded on the controller for it to work correctly
Because one time I was doing a microcontroller with a LCD screen controller display that I had not used before and because the routine was not run every time you turn on the device it would not display any thing at all but once I complied the program again now it shows up on the new LCD screen this could be issue hereComment
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The main difference between these LCD displays is the how the LED backlight is done. What pins for it, dropping resistor etc.
What happens when you rotate the contrast trimpot? You should see the pixels darken... or lighten.
Wait - is that a display heater or some nutty LED backlight in your pics? To "A1" "A2".Comment
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The wire coil that connects to A1 and A2 and goes around the LCD is the pick up coil for the G-Tag. I suspect that there is some kind of driver issue with this with the driver being loaded into one of the chips that are located underneath the LCD. I think I have gone as far as I can with this project without knowing more about how that LCD screen talks to the rest of the LCD board.Comment
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well - now you know
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Thanks. After reading this I can seen that the LCD has to be programmed which is what the problem is as I am only getting a single line of black blocks from it.Comment
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programmed?
it's a passive device, you just write the text to it together with stuff like position.
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Is the LCD module shown in your photos, the original, or the replacement?
The LCD modules already have the required program code in them to operate. You just need to send them the appropriate display data. The only "programming" that's really done is if specifying custom characters to be displayed, but this is also just data sent as part of normal operation (if that feature is being used)
(see https://en.wikipedia.org/wiki/Hitach...ontroller#Font)
The likely problem here is that your old display and the new display have different controller chips (HD44780 is one, but there are alternatives like SPLC780, KS0066, S6A0069)
They all function pretty much the same, but can have slight differences in timing requirements.
I expect your issue here is that your alarm CPU is sending the right commands to your LCD, but that the data is not being sent exactly at the right times, so it messes up and doesn't display correctly.
It's also possible there is some other fault with the unit as well, like the CPU stuck in reset or a missing voltage rail etc."Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
-David VanHornComment
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I have three Microsoft Surface Pro 5 model 1796, with all cracked screens.
Have bought from Aliexpress three new screens, the part numbers from my and the seller are the same:
Bad working China screen part number:
Good working own screen part number
Error I get with the bad working China screen:
No error with the good working own screen:
All the three China screens (all the same exact part numbers) produce the same error in Device manager. Have also performed a clean installation... -
Apologies if this is in the wrong section but being a car alarm siren that makes noise i thought it be best to put it in the audio section.
Had weird alarm issues where siren made a strange noise: https://www.youtube.com/watch?v=ZjsqndhionU
took siren out of the car and checked it out and pics attached seem to be the source of the issue.
shockingly the alarm still makes its normal sound if i trigger it manually so speaker seems to be intact.
getting a replacement is gonna be next to impossible, its a Toad Ai606 which is no longer in production and cant see to find a replacement... -
This house has a Honeywell Accenta G3 alarm system. If the main unit loses power for any reason, the external siren sounds - even if the alarm is not even armed! Entering the code to disarm it is not an option as the keypads are completely dead when the power is out.
I presume this means the backup battery inside the box has failed, but I can't get in there and replace it without also setting off a tamper alarm! Is there any way to disable the tamper alarm so that electrical work can be carried out with the power off? Or a way to replace the backup battery without setting off the... -
Hello all, I have a Dell Latitude 5420, before I upload the bios I thought I would ask. All I am getting is are coloured screens from one colure to another continuous that's all its doing.
I have searched on google some say this is a graphics problem and not a bios problem. I did try another bios file from the forum it stops at the Dell logo.
With the original chip fitted I am getting error code 3 amber and 3 white flashes.
Any advice please ?.09-02-2024, 03:43 AM -
I am trying to fix two flat tv screens. They have problems that I am not familiar how to deal with and if they are fixable at all.
1) the first TV is RCA 32: LCD combo tv+dvd, model RLCDV3282A-B. It was distorting images in sync with sounds. The sounds were distorted too. Then it was shutting down automatically. I replaced all visible electrolytic capacitors on power supply board. After repair, the image and sound are restored but tv still shuts downs unexpectedly usually after couple of minutes. I do not know what to do next. What might be the culprit and how to trace/inspect...
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