Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss

Old EPROM questions

32 views
Skip to first unread message

et...@whidbey.com

unread,
Mar 31, 2017, 11:58:42 AM3/31/17
to
All that know,
I have a machine tool made in 1985 that has, apparently, a faulty
circuit board. This board has EPROMs on it that I will need to remove
and insert into a replacement board that is coming to me. Aside from
making sure I am grounded to both the board and to the ground itself
are there any other precautions I should take? Also, when the machine
won'y be busy for a week or two I would like to get the EPROMs copied.
I could send them to someone but I am also considering doing the job
myself. I have other EPROMs of the same vintage that I can practice
with if I do the job myself but I don't know if this is something I
should try with the ones I really want back ups of. Any advice?
Thanks,
Eric

Phil Hobbs

unread,
Mar 31, 2017, 12:53:52 PM3/31/17
to
Assuming they're in the usual cheap sockets, I'd probably destroy the
sockets with a scalpel and bend the fingers out before removing the
EPROMs. In equipment that old, the pins may be corroded, and you don't
want one to fall off.

Cheers

Phil Hobbs
(Who has a lab full of top-of-the-line boat anchors. Love 'em.)

et...@whidbey.com

unread,
Mar 31, 2017, 1:20:38 PM3/31/17
to
I'll check to see if they are stuck. I don't think they will be though
because I have worked on even older FANUC controls and they all seem
to have been made pretty with pretty good components. I do have some
of theat DeOxit5 contact cleaner. Should I spray some on before
attempting removal?
Eric

John Robertson

unread,
Mar 31, 2017, 2:04:39 PM3/31/17
to
I'd think a spray of DeOxit would not hurt. It is rare for Eproms to
corrode though that depends on the storage environment I've pulled
thousands over the years from our arcade games from the 70s and 80s and
only a few legs had rotted. But those are easy to spot as the pins look
black!

If the leg is looking rotted consider unsoldering the EPROM socket with
the EPROM still installed. Then, leaving the EPROM in the socket, read
it in your programmer. Freeing the legs of the socket can be fun, best
to use a Pace or similar desoldering tool that allows you to move the
leg around while you are sucking the solder out.

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
(604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

tom

unread,
Mar 31, 2017, 2:08:43 PM3/31/17
to

<et...@whidbey.com> wrote in message
news:vvusdctkdaru2ar50...@4ax.com...
Remember that the EPROMS are static sensitive. Use appropriate anti static
procedures when working with those chips.

Google ESD for more details.



Jeff Liebermann

unread,
Mar 31, 2017, 3:32:24 PM3/31/17
to
On Fri, 31 Mar 2017 10:26:35 -0700, et...@whidbey.com wrote:

>I'll check to see if they are stuck. I don't think they will be though
>because I have worked on even older FANUC controls and they all seem
>to have been made pretty with pretty good components. I do have some
>of theat DeOxit5 contact cleaner. Should I spray some on before
>attempting removal?
>Eric

You're right about Fanuc using decent components.
Contact cleaner makes a mess and is not necessary.

It something like this Fanuc board?
<http://i.ebayimg.com/images/g/66cAAOSwd4tTrwpk/s-l500.jpg>
I used to help the owner of a local machine shop maintain a Mori Seiki
MV35-35 5 axis machining center, with a Fanuc something controller.
For upgrades, I never had a problem removing or inserting the EPROM's.
The coolant and oil fog that usually surrounds these machines does a
nice job of preventing corrosion. Watch out for the dehumidifier,
where condensation might make things rust.

Just pry out the EPROMS with a plastic pry tool or "spudger" (to
prevent cracking the ceramic EPROM case). Something like these:
<http://www.ebay.com/itm/161408350619>

Also, take a photograph of the PCB before disassembling so you can put
the EPROMs back in the correct socket.

For saving the EPROM contents, there are cheap EPROM burners available
on eBay. I have one like this:
<http://802.11junk.com/jeffl/K6BJ-MSF5000/Willem5.jpg>
About $50 on eBay:
<http://www.ebay.com/sch/i.html?_nkw=willem+eprom+programmer>
However, there are some tricks involved and it's all too easy to make
a mistake and trash an EPROM. If you're going to do this yourself, I
strongly suggest that you first practice with some junk EPROMs.

Good luck.

--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

et...@whidbey.com

unread,
Mar 31, 2017, 7:55:30 PM3/31/17
to
On Fri, 31 Mar 2017 11:04:32 -0700, John Robertson <sp...@flippers.com>
wrote:
Greetings John,
Fortunately the circuit board shows no corrosion. I do have a tool
made for removing these chips so I'll just give 'em a squirt. let the
stuff work for a bit, and then pull 'em.
Eric

John Robertson

unread,
Mar 31, 2017, 8:09:15 PM3/31/17
to
If no signs of corrosion, then I would not spray the board with anything.

Take great care that you do not damage traces under the socket when you
are prying out the EPROMs.

et...@whidbey.com

unread,
Mar 31, 2017, 8:19:45 PM3/31/17
to
On Fri, 31 Mar 2017 12:32:16 -0700, Jeff Liebermann <je...@cruzio.com>
wrote:
Greetings Jeff,
The board I am replacing has only 6 EPROMs but still looks similar.
Thanks for mentioning picture taking, I will for sure be doing that. I
didn't know the programmers were so inexpensive now. Since I have lots
of old EPROMs from a few other FANUC controls I am gonna order a
reader/programmer and see if I can copy the junk ones. So I'll be
asking for advice soon about which programmer to get for my particular
devices and how to avoid scrapping them.
Thanks,
Eric

et...@whidbey.com

unread,
Mar 31, 2017, 8:20:23 PM3/31/17
to
On Fri, 31 Mar 2017 14:10:07 -0400, "tom" <tmille...@verizon.net>
wrote:
I will for sure be taking all precautions regarding ESD.
Eric

Phil Hobbs

unread,
Apr 1, 2017, 12:11:12 PM4/1/17
to
Good idea.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

Jeff Liebermann

unread,
Apr 1, 2017, 12:37:27 PM4/1/17
to
On Fri, 31 Mar 2017 17:25:50 -0700, et...@whidbey.com wrote:

>The board I am replacing has only 6 EPROMs but still looks similar.

>Thanks for mentioning picture taking, I will for sure be doing that. I
>didn't know the programmers were so inexpensive now.

This is the one that I use:
<http://www.ebay.com/itm/291531758605>
$30 plus $10 shipping. Maybe add about $15 for a 9V power supply,
DB25 extension cable, and USB cable.

There is a later version that runs on a USB port:
<http://www.ebay.com/itm/290924359652>
$50 plus $14 shipping.

Notice that it uses a parallel port computah interface. Don't bother
trying a USB to parallel adapter cable. It won't work. Don't use a
ribbon cable for a DB25 extension. Mine went intermittent from
bouncing around in my car. I wasted a few days finding the problem.

>Since I have lots
>of old EPROMs from a few other FANUC controls I am gonna order a
>reader/programmer and see if I can copy the junk ones.

The hard part is getting the jumpers and switches correct. Don't
guess. One wrong switch or jumper and your device is blown. Also,
pay attention the EPROM manufacturer. Even though the chip number
might be similar, each mfg has a different voltage, timing, and
programming algorithm.

You'll also need an EPROM eraser. I suggest you get one with a drawer
that can handle more than one EPROM at a time. The UV light does not
last very long. If you're erasing one at a time, you'll burn out the
light after about 500 erases.
<https://www.google.com/search?q=eprom+eraser&tbm=isch>
<http://www.ebay.com/sch/i.html?_nkw=eprom+eraser>
The really cheap ones are fine and all the mechanical timers are noisy
and obnoxious.

>So I'll be
>asking for advice soon about which programmer to get for my particular
>devices and how to avoid scrapping them.
>Thanks,
>Eric

Chris Jones

unread,
Apr 2, 2017, 10:26:12 AM4/2/17
to
As I discovered in my youth, EPROMS can go into a socket two ways
around. One way is good, the other way is bad. When the supply and
ground pins are swapped like this, the bond wire melts and you can even
see the melted remains through the quartz window, which somehow makes it
more frustrating. If you are going to make this mistake, at least do it
AFTER you have a copy of the contents!
0 new messages