Hameg HM8118 repair - Page 1
Forum section: electronics / repair

author: TRN
author_rank: Unknown
timestamp: November 20, 2023, 03:38:36 pm
content: Hi,I recently purchased a defect HM8118 on eBay. This unit has several issues, one of which is that only half of the display is working,as you can see from the attached pictures.I managed to update the firmware from V1.47 to V1.57, but of course this did not fix the LCD problem.The LCD is a COG-LCM138-06 with serial number: 110111408422, and I presume that the one of the controllers on the LCD is faulty, and thus does not drive part of the LCD anymore.Does anybody have a spare working display for sale, or else can me provide a datasheet, because I searched the internet, and cannot find any information about the LCD; not even who manufactured it.I also could not find a service manual for the HM8118. If somebody has this a copy would be greatly appreciated.Here is all the info what is written on the LCD, and also on the separate backlight unit. (see also the pictures)FPC-LCM138-01, 2004.05.113810SHON58 VLCOG-LCM138-06WU621A-01LBL-LCM138-01A210/11/06Thanks

author: Hamelec
author_rank: Regular Contributor
timestamp: November 22, 2023, 10:31:02 pm
content: have a look into the comments ofMaybe Michel.Waleczek (at) gmail.com can help you out with a manual...

author: shakalnokturn
author_rank: Super Contributor
timestamp: November 23, 2023, 12:02:31 am
content: Good luck, sourcing this kind of display is a nightmare.Of course you could kindly ask Rhode & Schwartz for some information or spares.If you're on your own in the end, it can help searching to know the display resolution, number of pins on FPC and bus data format.

author: Hamelec
author_rank: Regular Contributor
timestamp: November 23, 2023, 08:38:01 am
content: cant believe that it is a failure of the display themselfes, more of the flexboard/connector or driver unit

author: coromonadalix
author_rank: Super Contributor
timestamp: November 23, 2023, 08:45:46 am
content: as for the problem, could be hw failure of the lcd matrix glass or on the flex lcd assembly or even the lcd controlleryes ask the company under an non disclosure agrrement if you can order the SV Manualor get that part ?Unless it's a customized onebecause of the 2x pcb traces groups on each side, i never see theses in lcd's ??

author: jchw4
author_rank: Regular Contributor
timestamp: November 23, 2023, 09:36:42 am
content: Quote from: Hamelec on November 23, 2023, 08:38:01 amExactly.The flex bonding looks very suspicious:Does it normally fold the flex cable back behind the display? I would try pressing the bond with pencil eraser and see whether it helps.My personal experience with trying to heat up and re-bond the flex cables under stress has been negative so far. It works until you fold the cable in place and then detaches again.You may be able to fold a piece of sheet metal to make a clip and attach it to the top to hold the flex cable. It worked for me once...

author: coromonadalix
author_rank: Super Contributor
timestamp: November 23, 2023, 03:24:59 pm
content: they are glued on the glass with conductive glue .... and sometimes having some hardware who push / press on theses could helpits a gamble

author: TRN
author_rank: Unknown
timestamp: November 25, 2023, 06:29:56 pm
content: Quote from: shakalnokturn on November 23, 2023, 12:02:31 amWell I have tried all angles to find any information and /or replacement of this display. But so far no luck. There is no information whatsoever available on the internet, so that seems to be a dead end.I also send an email to Sky-Messtechnik.de, which is the R&S authorized service company for Hameg equipment, and although they conduct component level repairs, they do not sell spare parts for the HM8118, nor do they handout service documentation for this unit.Just like R&S they have standard repair prices, which for the HM8118 is:Standard Repair Price is € 405,00 net incl. adjustment(repair on component level, re-adjustment without measurement protocol)If display or boards needed:Display + € 70,00 netMain Board + € 225,00 netCalibration + € 250,00 net (incl. measurement protocol from external calibration lab)So a repair would minimal cost me a hefty ( 405+70) +23% VAT = 584,00 EUR excluding the shipping cost from Portugal to Germany

author: TRN
author_rank: Unknown
timestamp: November 25, 2023, 06:31:01 pm
content: Quote from: coromonadalix on November 23, 2023, 03:24:59 pmOK I will try this

author: coromonadalix
author_rank: Super Contributor
timestamp: November 26, 2023, 02:29:43 am
content: the last resort would be to snif out the communication protocols with an logic analyser and figure out wich controller by chance they are using and finally finding the right lcd ??

author: TRN
author_rank: Unknown
timestamp: November 26, 2023, 11:11:46 am
content: Quote from: Hamelec on November 22, 2023, 10:31:02 pmHamelec,Thanks for this info, and I have contacted Michel, who responded that he is currently enjoying his vacationI will contact him again once he is back home

author: TRN
author_rank: Unknown
timestamp: November 26, 2023, 11:28:10 am
content: Quote from: jchw4 on November 23, 2023, 09:36:42 amYour hunch about the suspect flex bonding was correct.👍With the lcd installed in the unit, I flexed the cable in different positions, while booting the unit, and it booted once with a beautiful full working display.I then removed the lcd, put some light pressure on the bonding area, and reinstalled the lcdUnfortunately after this no more luck, so I must have screwed something up👎Anyway this proved that the lcd matrix and 2 controlers are ok.Does anybody know any company (preferably in Europe) which repairs flex bondings, and if so, what would be the estimate repair cost?

author: TRN
author_rank: Unknown
timestamp: November 26, 2023, 11:32:17 am
content: Quote from: coromonadalix on November 26, 2023, 02:29:43 amSniffing out the communication protocol, is probably doable, but trying to find the controller type will be a hard nut to crack

author: coromonadalix
author_rank: Super Contributor
timestamp: November 26, 2023, 02:06:53 pm
content: well i checked the video since some comments are in french (im native french)there was a substitution with an LCM 219 with a different bootloader for this lcd .... and this one too is a tough one to getR&S get bad points here for repairability, and for sure they know itit would mean to trace down lcd pinout on the main board and try to figure out the data lines etc ... i would be able if i have this lcr ... wich i dontlook like a 40x8 characters lcd for sure .... if i count them in their user manual images .... i dont think its a graphical one ??

author: CJay
author_rank: Super Contributor
timestamp: November 26, 2023, 04:39:54 pm
content: Quote from: coromonadalix on November 26, 2023, 02:06:53 pmI'm pretty convinced it's a graphical LCD, the third picture has an uninterrupted line of pixels down the display, character LCDs generally have 'gaps' between rows of characters.Looking at the includes and source files in the video linked give the impression it's a graphic one too, LCDDRAW.C and LCDTEXT.C, plus the Epson.c might indicate it could an Epson (compatible?) controller?The pictures are nearly good enough to count the pixels, I think it's almost definitely 64V just by counting but obvs counting pixels that aren't visible on the RH side makes it tricky, maybe 128H making it a 128x64 (maybe 138 which would mean custom?).There's 2 chips mounted on the glass and the flat flex looks as though there's a bunch of vias so they're 'in parallel' for the data and probably most control lines so there'll be a 'chip select' line somewhere.It might be useful to know the physical dimensions of the display.****Also might be interesting to see a little more of the CPU and memory, if it's got external program memory or there have been firmware updates it might give some clues to examine the contents?****Interesting, uses a PSD chip so it's 8052 based, firmware update is likely encrypted though

author: CJay
author_rank: Super Contributor
timestamp: November 26, 2023, 05:04:01 pm
content: SED controllers likely given the Epson.c in the source tree

author: coromonadalix
author_rank: Super Contributor
timestamp: November 26, 2023, 05:15:37 pm
content: goood catch haven't tought of that lolll should have checked more ....

author: TRN
author_rank: Unknown
timestamp: November 26, 2023, 08:19:21 pm
content: Quote from: CJay on November 26, 2023, 04:39:54 pmGood catch indeed, it is a graphics display.The owner of the video was so friendly to send me just now a copy of the module specifications.It is a Varitronixs COG LCM138 240 x 64 Dot graphics display which has 2 x Epson S1D10605 COG'sFor who's interested I have attached copies of the spec sheet and S1D10605 data sheet.

author: coromonadalix
author_rank: Super Contributor
timestamp: November 27, 2023, 01:16:58 am
content: just send them an email if they have a substitution ?? at least a 30 pins flex with all the signals ...and the controllersyep thats what i tought 2x chipselect,1x Enable pin ...dual S1D10605 lcd's ?http://www.3t-lcd.com/MechanicalSpec/Graphical/TMGG24064-XX.pdf22 pins lcd ?COG-BT240064-05https://www.farnell.com/datasheets/31889.pdf22 pins lcd ?TMGG24064-XXhttp://www.3t-lcd.com/MechanicalSpec/Graphical/TMGG24064-XX.pdf22 pins lcd ?the TMGG24064 is the one we get the most while searching ?https://i-lcd.com/LCD/Graphic/240x64.php

author: CJay
author_rank: Super Contributor
timestamp: November 27, 2023, 07:56:33 am
content: I like a result like that, finding and getting help from the designer is just great.Interesting solution to limited resolution controller chips too, I really hope you can find an alternative display.If you can't then it might be worth trying to track down one of the car LCD dashboard repairers, some of them have the equipment to rebond/replace the flat flex.

author: TRN
author_rank: Unknown
timestamp: November 27, 2023, 11:08:36 am
content: Quote from: coromonadalix on November 27, 2023, 01:16:58 am22pins means a serial interfaceUnfortunately this LCD has parallel interface

author: coromonadalix
author_rank: Super Contributor
timestamp: November 27, 2023, 11:13:40 am
content: I think you should check you received pdf from the designer before answering ....Check the pinouts and you'll learn that your has SPI lines, see SCL SI etc .... unless specifically written parallel operation and or 8088 interfacing etc .... witch the pdf doesn't tellWell thats all for me, it seem you have some stubbornness, i'll keep my comments for now and read onlyNow that you seem to have some connection from the designer, if he still wants to answer, ask him for substitutes, and do some search now that you got some answers on the 2x controller blobI think you may, in the end do some magic in the hardware and maybe firmware tooR&S should be made aware of this problem, unless they already know it, and not selling parts is not good even if you end up with a non calibrated unit, this is abusive behaviour.Theses lcd's are old or unobtanium and the other suggested are more recent, but still old in some models ...So sad to have an expensive lcr pludered by a now cheap lcd problem, take some courage and made it repaired ?

author: TRN
author_rank: Unknown
timestamp: November 27, 2023, 04:34:52 pm
content: Quote from: coromonadalix on November 27, 2023, 11:13:40 amHello coromonadalix,All your comments are well received and appreciated, so keep them coming, and I don't think I am stubbornI might be mistaken but the reason I mentioned that the protocol is parallel, because tracing the PCB, all 8 data lines are connected to the MCU via 51ohm resistors, and I figured that if SPI was used they would not have connected D0-D5, but only D6 & D7

author: coromonadalix
author_rank: Super Contributor
timestamp: November 27, 2023, 06:11:43 pm
content: ok i admit i'm in the wrong sorrycheck pin2 p/s the answer is theremaybe find some projects with similar displays .... and you have other 240x64 dual drivers like yours but in the standard physical metal framesome specs found todayhttps://www.crystalfontz.com/controllers/Epson/S1D10605/80/attached herefromhttps://www.crystalfontz.com/controllers/Epsonpossible substitutions ?? but 8088 mode and not the same controller .... would be nice to have help from the designerhttps://www.winstar.com.tw/products/graphic-lcd-display-module/240x64-lcd-display.htmlhttps://www.raystar-optronics.com/graphic-lcd-display-module/240x64-lcd-display.htmlhttps://www.raystar-optronics.com/upload_files/monochrome-lcd-module/240x64-graphic-lcd-dispaly/RG24064A2-datasheet.pdfhttps://www.orientdisplay.com/products/amg24064p-g-w6wfdw-4-3-240x64-cog-lcd-module/now i understand when you have 22 pins you loose the parallel mode ....so many driver ic's and possibilities .... but no access to the cpu code

author: TRN
author_rank: Unknown
timestamp: November 27, 2023, 08:39:02 pm
content: No problem, everybody makes mistakes once and a whileYep, pin 2 is connected to +3.3V, so the bus is parallel

author: TRN
author_rank: Unknown
timestamp: December 19, 2023, 07:35:21 pm
content: Ok here is a little update about the LCD saga of the HM8118.I sourced everywhere, and this LCD is really unobtainable. I contacted all the Varitronix subsidiaries around the world (now BOE Varitronix), most of them did not even reply, but I got some response from the Netherlands.They mentioned that they only can supply this with production volumes (i.e in the thousands).Also none of the Chinese LCD manufacturers in Shenzhen I contacted can supply this, except one who would charge me 1250US$ for opening and modifying the LCD production matrix.This supplier also mentioned that the production cost ex factory is +/- 3.5 US$ per piece.Also tried all companies worldwide which repair/refurbish Hameg equipment, but also they could not supply the LCD.What I don't understand is, that if these repair companies need to replace an LCD, where do they get it from? fore sure they don't order these in production quantities.Enough sorrow for now, until I have some more updates (if any)

author: coromonadalix
author_rank: Super Contributor
timestamp: December 19, 2023, 09:20:50 pm
content: means Hameg must have some leftovers in stock until they get no longer available ....that's why you may shell a lot of $$$ to get it repaired and calibrated .... it's your last chance ?

author: TRN
author_rank: Unknown
timestamp: December 29, 2023, 08:04:09 pm
content: Quote from: coromonadalix on December 19, 2023, 09:20:50 pmOr maybe notI bought myself an Andonstar Microscope for Christmas, and had a closer look at the LCD. and I found that flex-trace 29 & 30 had a hairline crack next to the 30 pin conector. After fixing this, the LCD is back to 100% working conditionNow I need to fix some other issues, because the previous owner really hacked around in this unit.

author: rob040
author_rank: Contributor
timestamp: December 29, 2023, 10:04:00 pm
content: Wow, well done!Saves a lot of money.Beautiful instrument!

author: p.larner
author_rank: Frequent Contributor
timestamp: December 30, 2023, 08:19:05 pm
content: cool outcome on a nice piece of kit,what model addonis microscope did you buy,have you the link or seller details?,cheers+73

author: TRN
author_rank: Unknown
timestamp: December 30, 2023, 08:50:00 pm
content: I bought a Andonstar AD409 Pro-ES HDMI Digital Microscope with 10.1" LCD.Regular price was €449.00, but Elektor.com has promotion with a 33% discount so €299.00Here is the link:https://www.elektor.com/andonstar-ad409-pro-es-hdmi-digital-microscope-with-10-1-lcd-screen-incl-endoscopeRegards

author: lab@zigbee.cl
author_rank: Newbie
timestamp: August 20, 2024, 10:15:18 am
content: We had the same problem with this discontinued Epson 2 x COG LCD controller, we did a compatibility analysis with the ones currently in production and we came up with the ST7565 controller, it is almost exact.There is an LCD sold by Digikey with this controller and 240 x 64, exactly the same and for only US$ 28.xx. With exactly the same dimensions, same connections and electronic conditions.See this information atwww.digikey.com, it is a real solution.Manufacturer = MIDAS.Part number = MCCOG240064A16W-BNMLW

author: lab@zigbee.cl
author_rank: Newbie
timestamp: August 20, 2024, 10:21:28 am
content: We had the same problem with this discontinued Epson 2 x COG LCD controller, we did a compatibility analysis with the ones currently in production and we came up with the ST7565 controller, it is almost exact.There is an LCD sold by Digikey with this controller and 240 x 64, exactly the same and for only US$ 28.xx. With exactly the same dimensions, same connections and electronic conditions.See this information atwww.digikey.com, it is a real solution.Manufacturer = MIDAS.Part number = MCCOG240064A16W-BNMLW