Subject:	Broken Autostar LCD
Sent:	Wednesday, April 1, 2009 08:33:10
From:	dbodish@comcast.net (dbodish@comcast.net)
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 (michele.renda@gmail.com)
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

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