AUTOSTAR LCD REPLACEMENT
Last updated: 12 December 2012
Subject: Broken Autostar LCD Sent: Wednesday, April 1, 2009 08:33:10 From: firstname.lastname@example.org (email@example.com) I wanted to close the loop on my broken handset LCD story. A month ago, I dropped my brand new 497 and cracked the LCD module. I've been on a quest to fix it, and I've learned a few things that may be of interest to others who are as clumsy and unlucky as me. This is a long post and may be of interest to only a few of your readers, so file it where you think appropriate. First off, I fixed my Autostar in the obvious and easy way. I bought a cheap, secondhand 497 on ebay, and swapped out the LCD module. This is an easy fix that anybody who can use a screwdriver can do in five minutes. The LCD module in recent 497s is a chip-on-glass or COG unit. The entire module is encased in a glass plate only about 2 mm thick, and is very easily damaged by impact. When I opened my 497, the LCD was in several pieces. The COG module attaches to the PCB via an integral 14 pin flex-film ribbon that comes out of a tab below the display itself. Once the case is off, all you have to do is release the old ribbon from the circuit board by sliding out the locking sleeve on the docking fitting, inserting the new ribbon from the new LCD unit, and locking it into place. Done. It was actually easier to just leave the LCD attached to the front case it was in, so I really just moved the new PCB to the old case. I used the new rubber keypad as well, so I'm as good as new again in every way that matters. I then had one working 497, and a backup that was functional, except for the LCD. I started looking for a replacement part, but Meade doesn't provide one, and I couldn't identify a part number from the old unit or match it to anything in the manufacturer's inventory. There are hundreds of LCD modules for sale out there, all slightly different. The 497 module is a 16 x 2 (characters x lines) alphanumeric COG. It has no integrated backlighting, being backlit instead by PCB-mounted LEDs, shining through a plastic diffuser behind the module. It has a transmissive screen that is normally opaque, with the backlighting shining only through the active characters. This is why the text seems to glow like a LED screen. The approximate dimensions of the module are 69.5mm x 27.5mm x 2mm thick, and the two line display lies above the centerline of the module, which means it only fits in one way. In the thread you pointed me to, Dick Seymour suggested a couple of possible replacements from the Digi-Key catalog, but neither was really a good fit. There is really no room to spare in the 497 case in either the height or thickness dimensions. You could perhaps get a longer unit in there, but would have to do a little surgery on the internals of the plastic case to make things fit snugly and still have the case close. Obviously, the display area has to be pretty close to that of the stock unit to be viewable through the case. I took my inspiration from Dick and surfed some electronic supplier and manufacturer inventories. The best candidate I found was a COG module made by Hantronix, model HDG1602. It is almost a perfect fit, has a 14 pin interface, and it comes in three versions, one of which has an integral flex-film ribbon with the same spacing as the factory module (HDG1602-F1). That's the good news. The bad news is, I can't find a supplier who will sell me a single unit of the F1 version. Mouser Electronics, one of the biggest low volume component suppliers out there, does stock a solder pin version (HDG1602-P2). Same size, but no convenient film ribbon. Now for the ugly - the P2 version has the tab with the contacts above the display, not below, with the display area offset to the bottom, not the top of the module. This means you can only install it upside down in the 497 if you want the display to line up with the viewing window. There is supposedly a P1 version that has the correct orientation with the solder contacts below, but I can't source that one either. I recently ordered some stuff from Mouser, so I picked up an HDG1602-P2 for $8.58, figuring any display is better than none. I soldered it into my backup unit (using 30 AWG single conductor Kynar-coated wire), and amazingly enough, it works! I now have a fully functional backup 497.... with an upside down display. I've attached a couple of photos of the installation and the result. One other difference you will see in the photos - the Hantronix display is the more typical reflective LCD, not transmissive. The 497 backlighting still works, but you get a red field with black text rather than the other way around. It is actually much easier to read in daylight. At night, I prefer the stock red characters, but both work. I can't honestly say I recommend this repair, given the availability of cheap used handsets (I got mine for $50 on ebay, including shipping), but if somebody wants to replace a LCD, it can be done. Maybe there is somebody out there who really wants an inverted 497 screen (maybe one of your southern hemisphere viewers?). Maybe somebody will take the time to modify the case window so they can install the LCD right side up. I considered that, but took the easier path. Best of all, maybe somebody will find a source for the F1 version or equivalent, making soldering and standing on your head unnecessary. I tried to interest Mouser in giving me a quote, but it was 100 units minimum. If somebody knows a low volume source for a more direct replacement module, I'd love to hear about it. These things are far too easy to break. One final note I feel obliged to add - soldering the 14 tiny leads does require a moderate level of soldering expertise. I'm a rank amateur, but I have the right tools and some experience modding PCBs. This took me less than an hour, but If people have never soldered jumpers on IC legs before, they may want to consider whether they want to take this on. You could take that $8.50, buy a six pack of top quality Northwest microbrew, and probably have a more enjoyable evening than learning to solder PCBs. On the other hand, knowing how to solder is handy. If you choose the latter, read a good tutorial and practice first on some junk boards. If anybody else is deranged enough to try this, I'd be happy to offer tips or answer questions. Hantronix spec sheets for all their displays can be found here: hantronix.com/2_3.html Mouser stock on the model I bought is here: mouser.com/Search/ProductDetail.aspx?qs=NSR9MB9QqxZ6sP6%252brbe3ww%3d%3d Cheers, Donovan Bodishbaugh Seattle
Sent: Monday, December 10, 2012 12:34:25 From: Michele Renda (firstname.lastname@example.org) In answer to this email: http://www.weasner.com/etx/autostar/2009/lcd_replacement.html I bought a second hand etx-70 with a LCD broken 494 Autostar. I searched for info about LCD replacement and arrived to this page. I tried to find a HDG1602F-1 module but now they are impossible to find. I found the module datasheet but despite it has a 4 pin flat cable, the pin order is not compatible with the socket of 494. The right pin order is described in the datasheet of HDG1602P-1. I had at home a very cheap LCD display bought on Ebay and I noticed the pin order was very similar. The LCD code is SC162A3 and has almost the same pin order. The only thing to add is a trimmer to set the contrast. I fixed it with a flex cable (took by an old IDE cable) and it just worked. The only problem is that the unit is too big to fit inside the pad, so it must be set externally. I hope this info will help someone. Best regards Michele Renda
Go back to the Autostar Information page.
Go back to the ETX Home Page.