Gamma spectrometer repair - Page 1
Forum section: electronics / repair

author: Gammababa
author_rank: Newbie
timestamp: August 11, 2023, 12:34:44 pm
content: Hi everyone,I'm currently repairing a GR130 gamma spectrometer and survey meter.After repairing some broken solder joint, it seems to work well but the screen is broken...The original screen is a Seiko G121C rev B.Searching on internet for replacement part, they seem to be hard to find and the price is quite high (approximately 300 €...) and the manufacturer tell me that not all rev of the screen work.How could i found if a screen is compatible without spending 300€ ? :'(ThanksBaptiste

author: JacobPilsen
author_rank: Regular Contributor
timestamp: August 11, 2023, 05:09:57 pm
content: Is the LCD itself bad?That display doesn't look mechanically damaged.Couldn't there be a fault in the electronics?There are some (addresing ?) "jumpers" J1 to J10.Their different soldering can also cause incompatibility.

author: Swake
author_rank: Frequent Contributor
timestamp: August 12, 2023, 10:24:32 pm
content: Datasheet of screen attached. You'll have to compare the specs with the one you'd buy.From your pics I believe only one chip is custom. All else can be repairedProbably very time consuming idea: Try make that LCD work from an Arduino or something similar to confirm your issue is indeed with the LCD.

author: fmashockie
author_rank: Frequent Contributor
timestamp: August 20, 2023, 05:04:46 pm
content: How did you determine the LCD itself is bad? Swake just added the datasheet for the screen which is awesome. Should be very helpful in determining whether its the LCD or the driver thats the problem.

author: coppercone2
author_rank: Super Contributor
timestamp: August 20, 2023, 05:21:00 pm
content: it looks like a fluke scope meter internals

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 20, 2023, 05:22:54 pm
content: Displays like this usually have an oddball supply voltage - if this supply isn't there it would give a "no display but otherwise working" symptomDatasheet here :https://html.alldatasheet.com/html-pdf/80594/SII/G121C00P000/215/4/G121C00P000.html

author: Gammababa
author_rank: Newbie
timestamp: August 25, 2023, 10:17:23 am
content: Hi everyone, sorry for late answer.I think the problem is the screen because when i firt power on the device, i get the lower half of the screen working but the upper half is blinking with no image.I dismount the screen bezel and it seem that there is some cracks in the pannel at the lower left corner (see image 1, the result is the same with the bezel don't mind the kapton tape).After cleaning the zebra strips on both sides and pplaying with the position of the screen, i managed to get an almost complete display (image 2) but after 1 or 2 minutes without touching anything, it goes like on image one.It's look like the hot bar attachement like in Dave's video 1192 have failed...After all of that, given the fact that the device fall before been thrown to the dumpster make me think that the screen is broken.Any advice to try fix it ?Thanks for all your answersBest regardsBaptiste

author: Swake
author_rank: Frequent Contributor
timestamp: August 25, 2023, 10:48:08 am
content: Indeed seems to be a connectivity issue. Try pressing that ribbon cable down PCB side. With some foam or rubber.There are still some lines missing from the zebra connector, but I guess these will taken care ones the bezel is put back.Have seen other LCD's with those liquid smudge on the borders, many still. It is more a sign of age in my opinion, it will probably end up failing sometime in the future.

author: fmashockie
author_rank: Frequent Contributor
timestamp: August 26, 2023, 05:12:41 am
content: Have you tried reheating the hotbar attachment? I've seen a few videos where Dave does this with good success and limited experience doing it prior (at least he claims). If you have a hot-air gun and something soft like a pencil eraser, add heat the hotbar while pressing down on the strip. If the screen really is broke, you have nothing to loose.