Kind of a generic electrolytic cap question

One of my CNC machines has a circuit board that has failed 3 times
now. The control is a FANUC 3T. It is an older control so failing
boards don't surprise me. But it is just the one board. This board has
many custom hybrid ICs, some other of the shelf ones, 6 EPROMs, and
one electrolytic capacitor. I have checked this cap on two boards with
my meter and the cap has the stated value and is not shorted. But I
don't have a way to check ESR.
The failure mode for all the boards is the same. First the turret
on this lathe will occasionally index in the wrong direction. After
the machine is powered up for a while it will then start to index
properly. I can control the turret rotation from a program but when
the board starts to fail it will only index in one direction.
Furthermore, then turret should always rotate in the direction that
is the shortest to the next tool called up, but when the board starts
going bad the turret still only indexes in one direction.
Unfortunately this is the wrong direction.
After this failure other things start going wrong, like the speed
control. Changing the boards has always fixed the problem. Note that
when I change the boards I have to swap all the EPROMs so that the
programming for the machine operation will be the same.
Since all the boards seem to fail the same way I was wondering if
somehow a failing cap could cause this failure. Even though the cap
value reads fine with my VOM, that does not measure ESR.
In any case I'm gonna order some caps and see if anything changes
but I would like to know if it is probably gonna be a waste of time.
Thanks,
Eric

 

[John Robertson]

On 2019/11/14 12:20 p.m., etpm@whidbey.com wrote:

One of my CNC machines has a circuit board that has failed 3 times
now. The control is a FANUC 3T. It is an older control so failing
boards don't surprise me. But it is just the one board. This board has
many custom hybrid ICs, some other of the shelf ones, 6 EPROMs, and
one electrolytic capacitor. I have checked this cap on two boards with
my meter and the cap has the stated value and is not shorted. But I
don't have a way to check ESR.
The failure mode for all the boards is the same. First the turret
on this lathe will occasionally index in the wrong direction. After
the machine is powered up for a while it will then start to index
properly. I can control the turret rotation from a program but when
the board starts to fail it will only index in one direction.
Furthermore, then turret should always rotate in the direction that
is the shortest to the next tool called up, but when the board starts
going bad the turret still only indexes in one direction.
Unfortunately this is the wrong direction.
After this failure other things start going wrong, like the speed
control. Changing the boards has always fixed the problem. Note that
when I change the boards I have to swap all the EPROMs so that the
programming for the machine operation will be the same.
Since all the boards seem to fail the same way I was wondering if
somehow a failing cap could cause this failure. Even though the cap
value reads fine with my VOM, that does not measure ESR.
In any case I'm gonna order some caps and see if anything changes
but I would like to know if it is probably gonna be a waste of time.
Thanks,
Eric

I'd say it is unlikely the capacitor is the problem - normally these are
used to smooth the Vcc to the chips. You say there are custom chips on
the board, so depending on if you can get schematics or not then you may
be looking at the rest of the circuits.

Regular electrolytic caps are rarely used for critical timing, rather
they would use a tantalum cap if the value was important.

If you want to check the ESR then Bob Parker's Blue ESR meter kit is not
a bad way to go...available here (flippers.com - shameless plug!) and
there...

However I don't think the cap is responsible for your problems.

Have you tried simply reseating the chips and connectors to the PCB and
any readouts, sensors, etc. in case it may be that simply reseating
plugs fixes the problem?

If the problem is only apparent after the machine has been on a while
have you checked the temperature of the logic? Chips don't like being
more than 50C by and large, and the cooler they run the better. A heat
gun and some cold spray may help find the sensitive IC as you say the
problem goes away when the system is warm.

John :-#)#

 

[Ralph Mowery]

In article <68crset030lbht7eq52p34vogu6lmvqj61@4ax.com>,
etpm@whidbey.com says...

One of my CNC machines has a circuit board that has failed 3 times
now. The control is a FANUC 3T. It is an older control so failing
boards don't surprise me. But it is just the one board. This board has
many custom hybrid ICs, some other of the shelf ones, 6 EPROMs, and
one electrolytic capacitor. I have checked this cap on two boards with
my meter and the cap has the stated value and is not shorted. But I
don't have a way to check ESR.

The capacitor probably only costs a few dollars at most. Just replace
it and see if the board comes back to life. That is see if the machine
acts normally.

 

On Thu, 14 Nov 2019 13:03:28 -0800, John Robertson <spam@flippers.com>
wrote:

On 2019/11/14 12:20 p.m., etpm@whidbey.com wrote:
One of my CNC machines has a circuit board that has failed 3 times
now. The control is a FANUC 3T. It is an older control so failing
boards don't surprise me. But it is just the one board. This board has
many custom hybrid ICs, some other of the shelf ones, 6 EPROMs, and
one electrolytic capacitor. I have checked this cap on two boards with
my meter and the cap has the stated value and is not shorted. But I
don't have a way to check ESR.
The failure mode for all the boards is the same. First the turret
on this lathe will occasionally index in the wrong direction. After
the machine is powered up for a while it will then start to index
properly. I can control the turret rotation from a program but when
the board starts to fail it will only index in one direction.
Furthermore, then turret should always rotate in the direction that
is the shortest to the next tool called up, but when the board starts
going bad the turret still only indexes in one direction.
Unfortunately this is the wrong direction.
After this failure other things start going wrong, like the speed
control. Changing the boards has always fixed the problem. Note that
when I change the boards I have to swap all the EPROMs so that the
programming for the machine operation will be the same.
Since all the boards seem to fail the same way I was wondering if
somehow a failing cap could cause this failure. Even though the cap
value reads fine with my VOM, that does not measure ESR.
In any case I'm gonna order some caps and see if anything changes
but I would like to know if it is probably gonna be a waste of time.
Thanks,
Eric


I'd say it is unlikely the capacitor is the problem - normally these are
used to smooth the Vcc to the chips. You say there are custom chips on
the board, so depending on if you can get schematics or not then you may
be looking at the rest of the circuits.

Regular electrolytic caps are rarely used for critical timing, rather
they would use a tantalum cap if the value was important.

If you want to check the ESR then Bob Parker's Blue ESR meter kit is not
a bad way to go...available here (flippers.com - shameless plug!) and
there...

However I don't think the cap is responsible for your problems.

Have you tried simply reseating the chips and connectors to the PCB and
any readouts, sensors, etc. in case it may be that simply reseating
plugs fixes the problem?

If the problem is only apparent after the machine has been on a while
have you checked the temperature of the logic? Chips don't like being
more than 50C by and large, and the cooler they run the better. A heat
gun and some cold spray may help find the sensitive IC as you say the
problem goes away when the system is warm.

John :-#)#

Greetings John,
Actually the machine starts to work after it has warmed up for a
while. I have tried the whole contact cleaning route several times and
it has had no effect on this machine.
Today I tried out two boards that I got used from eBay. One worked
and the other, whil it indexed then turret OK would not allow
programmed speed changes.
The speed change fault is mysterious to me and it has happened on
another board. The mystery is because of what the fault does.
Niormally speed changes while running a program can only happen from
programmed speed changes or from the constant surface speed command.
But when the board goes bad then the spindle speed can only be
controlled by the dial used for speed changes when in jog mode. And
that dial normally does not work when running a program.
I checked all the parameters and they have not changed. And the
EPROMs that hold the ladder programs for the machine are not affected.
In fact, I have to change them from board to board.
Speaking of EPROMs, I am ordering a GQ-4x4 programmer so I can copy
my EPROMs. I am really afraid I will destroy one one of these days. I
have lots of 2716 and 27C16 EPROMs that I can erase and re-program.
The machine has in it some 2716 and 2516 devices and I was told that
the 2516 devices should not be used. I am hoping the programmer can
read the 2516 devices.
Thanks,
Eric

 

On Thu, 14 Nov 2019 17:35:48 -0500, Ralph Mowery
<rmowery28146@earthlink.net> wrote:

In article <68crset030lbht7eq52p34vogu6lmvqj61@4ax.com>,
etpm@whidbey.com says...
One of my CNC machines has a circuit board that has failed 3 times
now. The control is a FANUC 3T. It is an older control so failing
boards don't surprise me. But it is just the one board. This board has
many custom hybrid ICs, some other of the shelf ones, 6 EPROMs, and
one electrolytic capacitor. I have checked this cap on two boards with
my meter and the cap has the stated value and is not shorted. But I
don't have a way to check ESR.



The capacitor probably only costs a few dollars at most. Just replace
it and see if the board comes back to life. That is see if the machine
acts normally.

Yeah, I am gonna do that. I just won't get my hopes up.
Eric

 

[John-Del]

On Thursday, November 14, 2019 at 3:20:47 PM UTC-5, et...@whidbey.com wrote:

One of my CNC machines has a circuit board that has failed 3 times
now. The control is a FANUC 3T. It is an older control so failing
boards don't surprise me. But it is just the one board. This board has
many custom hybrid ICs, some other of the shelf ones, 6 EPROMs, and
one electrolytic capacitor. I have checked this cap on two boards with
my meter and the cap has the stated value and is not shorted. But I
don't have a way to check ESR.
The failure mode for all the boards is the same. First the turret
on this lathe will occasionally index in the wrong direction. After
the machine is powered up for a while it will then start to index
properly. I can control the turret rotation from a program but when
the board starts to fail it will only index in one direction.
Furthermore, then turret should always rotate in the direction that
is the shortest to the next tool called up, but when the board starts
going bad the turret still only indexes in one direction.
Unfortunately this is the wrong direction.
After this failure other things start going wrong, like the speed
control. Changing the boards has always fixed the problem. Note that
when I change the boards I have to swap all the EPROMs so that the
programming for the machine operation will be the same.
Since all the boards seem to fail the same way I was wondering if
somehow a failing cap could cause this failure. Even though the cap
value reads fine with my VOM, that does not measure ESR.
In any case I'm gonna order some caps and see if anything changes
but I would like to know if it is probably gonna be a waste of time.
Thanks,
Eric

I work on a lot of industrial equipment for two local machine shops, and electros do go.

They bring me the suspected boards but I have them well trained to first heat the boards with a heat gun (without crisping them) and report if the normal operation is restored when heated.

If so, the first thing to get checked is the electros. I pull every one and test them for value, ESR, and dielectric absorption. Testing ESR in circuit on many modern circuit boards is a waste of time.

99% of the time a board that works normally when heated has a lazy electrolytic.

If the electro replacement doesn't fix it, try cooling individual parts to see if you can get it to act up.

 

[Ralph Mowery]

In article <ad5da084-f6ed-492e-8d5e-c989be6c3d03@googlegroups.com>,
ohger1s@gmail.com says...

eport if the normal operation is restored when heated.

If so, the first thing to get checked is the electros. I pull every one and test them for value, ESR, and dielectric absorption. Testing ESR in circuit on many modern circuit boards is a waste of time.

Once pulled, you might as well not test them, just replace them.

You may want to test the new ones before you put them in.

 

[Cursitor Doom]

On Thu, 14 Nov 2019 18:32:29 -0800, John-Del wrote:

99% of the time a board that works normally when heated has a lazy
electrolytic.

Or a dry solder joint somewhere on the board.

If the electro replacement doesn't fix it, try cooling individual parts
to see if you can get it to act up.

Good call. For which you can use stuff like 'pipe freeze' or 'Arctic
freeze' with the fine straw inserted - sold at your local plumbing
supplies. Clean the board with IPA afterwards.




--
This message may be freely reproduced without limit or charge only via
the Usenet protocol. Reproduction in whole or part through other
protocols, whether for profit or not, is conditional upon a charge of
GBP10.00 per reproduction. Publication in this manner via non-Usenet
protocols constitutes acceptance of this condition.

 

[Cursitor Doom]

On Thu, 14 Nov 2019 18:32:29 -0800, John-Del wrote:

If so, the first thing to get checked is the electros. I pull every one
and test them for value, ESR, and dielectric absorption. Testing ESR in
circuit on many modern circuit boards is a waste of time.

Why so?



--
This message may be freely reproduced without limit or charge only via
the Usenet protocol. Reproduction in whole or part through other
protocols, whether for profit or not, is conditional upon a charge of
GBP10.00 per reproduction. Publication in this manner via non-Usenet
protocols constitutes acceptance of this condition.

 

[John-Del]

On Friday, November 15, 2019 at 4:45:16 AM UTC-5, Cursitor Doom wrote:

On Thu, 14 Nov 2019 18:32:29 -0800, John-Del wrote:


If so, the first thing to get checked is the electros. I pull every one
and test them for value, ESR, and dielectric absorption. Testing ESR in
circuit on many modern circuit boards is a waste of time.

Why so?

Too many circuits these days use a small value SMD multi layer chip capacitor bypassing an electrolytic. These chip caps have ESR figures as low or lower than most electrolytics you're likely to run across despite being small value caps.

 

[John-Del]

On Thursday, November 14, 2019 at 11:14:21 PM UTC-5, Ralph Mowery wrote:

In article <ad5da084-f6ed-492e-8d5e-c989be6c3d03@googlegroups.com>,
ohger1s@gmail.com says...
eport if the normal operation is restored when heated.

If so, the first thing to get checked is the electros. I pull every one and test them for value, ESR, and dielectric absorption. Testing ESR in circuit on many modern circuit boards is a waste of time.




Once pulled, you might as well not test them, just replace them.

You may want to test the new ones before you put them in.

If you know the board *will* be fixed and put back in service, then yes, by all means replace them. But if I pull an electro during testing and it's good, I put it back and continue working on the board. No sense changing good caps on a board that may have to be replaced, like OP is dealing with.

Lots of these industrial boards use custom ICs, ICs and semis that have been intentionally defaced, and processor ICs for which there is just no data. Sometimes you just have to replace a board.

 

[John Robertson]

On 2019/11/15 5:26 a.m., John-Del wrote:

On Friday, November 15, 2019 at 4:45:16 AM UTC-5, Cursitor Doom wrote:
On Thu, 14 Nov 2019 18:32:29 -0800, John-Del wrote:


If so, the first thing to get checked is the electros. I pull every one
and test them for value, ESR, and dielectric absorption. Testing ESR in
circuit on many modern circuit boards is a waste of time.

Why so?


Too many circuits these days use a small value SMD multi layer chip capacitor bypassing an electrolytic. These chip caps have ESR figures as low or lower than most electrolytics you're likely to run across despite being small value caps.

Except this machine is from 1982 (paper tape readers, etc.) - so any
electros are primary smoothing ones for Vcc.

http://cncmanual.com/download/1647/

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

 

[John Robertson]

On 2019/11/14 4:01 p.m., etpm@whidbey.com wrote:

On Thu, 14 Nov 2019 13:03:28 -0800, John Robertson <spam@flippers.com
wrote:

On 2019/11/14 12:20 p.m., etpm@whidbey.com wrote:
One of my CNC machines has a circuit board that has failed 3 times
now. The control is a FANUC 3T. It is an older control so failing
boards don't surprise me. But it is just the one board. This board has
many custom hybrid ICs, some other of the shelf ones, 6 EPROMs, and
one electrolytic capacitor. I have checked this cap on two boards with
my meter and the cap has the stated value and is not shorted. But I
don't have a way to check ESR.
The failure mode for all the boards is the same. First the turret
on this lathe will occasionally index in the wrong direction. After
the machine is powered up for a while it will then start to index
properly. I can control the turret rotation from a program but when
the board starts to fail it will only index in one direction.
Furthermore, then turret should always rotate in the direction that
is the shortest to the next tool called up, but when the board starts
going bad the turret still only indexes in one direction.
Unfortunately this is the wrong direction.
After this failure other things start going wrong, like the speed
control. Changing the boards has always fixed the problem. Note that
when I change the boards I have to swap all the EPROMs so that the
programming for the machine operation will be the same.
Since all the boards seem to fail the same way I was wondering if
somehow a failing cap could cause this failure. Even though the cap
value reads fine with my VOM, that does not measure ESR.
In any case I'm gonna order some caps and see if anything changes
but I would like to know if it is probably gonna be a waste of time.
Thanks,
Eric


I'd say it is unlikely the capacitor is the problem - normally these are
used to smooth the Vcc to the chips. You say there are custom chips on
the board, so depending on if you can get schematics or not then you may
be looking at the rest of the circuits.

Regular electrolytic caps are rarely used for critical timing, rather
they would use a tantalum cap if the value was important.

If you want to check the ESR then Bob Parker's Blue ESR meter kit is not
a bad way to go...available here (flippers.com - shameless plug!) and
there...

However I don't think the cap is responsible for your problems.

Have you tried simply reseating the chips and connectors to the PCB and
any readouts, sensors, etc. in case it may be that simply reseating
plugs fixes the problem?

If the problem is only apparent after the machine has been on a while
have you checked the temperature of the logic? Chips don't like being
more than 50C by and large, and the cooler they run the better. A heat
gun and some cold spray may help find the sensitive IC as you say the
problem goes away when the system is warm.

John :-#)#
Greetings John,
Actually the machine starts to work after it has warmed up for a
while. I have tried the whole contact cleaning route several times and
it has had no effect on this machine.
Today I tried out two boards that I got used from eBay. One worked
and the other, whil it indexed then turret OK would not allow
programmed speed changes.
The speed change fault is mysterious to me and it has happened on
another board. The mystery is because of what the fault does.
Niormally speed changes while running a program can only happen from
programmed speed changes or from the constant surface speed command.
But when the board goes bad then the spindle speed can only be
controlled by the dial used for speed changes when in jog mode. And
that dial normally does not work when running a program.
I checked all the parameters and they have not changed. And the
EPROMs that hold the ladder programs for the machine are not affected.
In fact, I have to change them from board to board.
Speaking of EPROMs, I am ordering a GQ-4x4 programmer so I can copy
my EPROMs. I am really afraid I will destroy one one of these days. I
have lots of 2716 and 27C16 EPROMs that I can erase and re-program.
The machine has in it some 2716 and 2516 devices and I was told that
the 2516 devices should not be used. I am hoping the programmer can
read the 2516 devices.
Thanks,
Eric

Hi Eric,

If those are TI TMS2516 then they are equivalent to regular Intel 2716s.
The TMS2716 by TI had a triple supply and A10 was displaced.

TMS2716 vs regular 2716s

https://www.dropbox.com/s/7xaz0b829bhha6b/TMS2716vs2716.jpg?dl=0

TMS2516 (Thanks JRock for hosting):

http://www.jrok.com/datasheet/TMS2516.pdf

I don't know about the dependability of the TMS2516, but I would back up
ALL EPROMs just for safeties sake!

I hope your new EPROM reader can handle the 2716s, if not if it can read
2732s then you will get the data twice and you can split off the high
and low sections.

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

 

[Chuck]

On Fri, 15 Nov 2019 08:42:37 -0800, John Robertson <spam@flippers.com>
wrote:

On 2019/11/15 5:26 a.m., John-Del wrote:
On Friday, November 15, 2019 at 4:45:16 AM UTC-5, Cursitor Doom wrote:
On Thu, 14 Nov 2019 18:32:29 -0800, John-Del wrote:


If so, the first thing to get checked is the electros. I pull every one
and test them for value, ESR, and dielectric absorption. Testing ESR in
circuit on many modern circuit boards is a waste of time.

Why so?


Too many circuits these days use a small value SMD multi layer chip capacitor bypassing an electrolytic. These chip caps have ESR figures as low or lower than most electrolytics you're likely to run across despite being small value caps.


Except this machine is from 1982 (paper tape readers, etc.) - so any
electros are primary smoothing ones for Vcc.

http://cncmanual.com/download/1647/

John :-#)#

Some Grass Valley products from the early 80s had electrolytics that
would open but the surrounding circuitry would cause an ESR meter to
read very low ESR. Once the electrolytic was pulled, it would test
bad.

 

[Ron D.]

The EProms can cause issues when they age.

From my days of programming the 2716's. My programmer was semi-manual and it was really sensitive to the the programming voltage.

An EEprom may not have been erased completely.

Do inspect the board for bad solder joints.

Freeze spray can sometimes help make equipment fail or work. On a non-powered board, it can help highlight a bad solder joint.

 

[John Robertson]

On 2019/11/15 10:56 a.m., Ron D. wrote:

The EProms can cause issues when they age.

From my days of programming the 2716's. My programmer was semi-manual and it was really sensitive to the the programming voltage.

An EEprom may not have been erased completely.

Do inspect the board for bad solder joints.

Freeze spray can sometimes help make equipment fail or work. On a non-powered board, it can help highlight a bad solder joint.

My Xeltek 610P programmer has a feature where it will test EPROMs at +/-
10% of the voltage to help weed out iffy burns or EPROMs.

Recently I had some EPROMs I was verifying and they failed the
over-voltage test - so I reprogrammed them (not erased, just hit them
with the programmer burn process) and then they tested just fine. I
assume I recharged the gates so all was then well.

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

 

On Fri, 15 Nov 2019 11:27:05 -0800, John Robertson <spam@flippers.com>
wrote:

On 2019/11/15 10:56 a.m., Ron D. wrote:
The EProms can cause issues when they age.

From my days of programming the 2716's. My programmer was semi-manual and it was really sensitive to the the programming voltage.

An EEprom may not have been erased completely.

Do inspect the board for bad solder joints.

Freeze spray can sometimes help make equipment fail or work. On a non-powered board, it can help highlight a bad solder joint.


My Xeltek 610P programmer has a feature where it will test EPROMs at +/-
10% of the voltage to help weed out iffy burns or EPROMs.

Recently I had some EPROMs I was verifying and they failed the
over-voltage test - so I reprogrammed them (not erased, just hit them
with the programmer burn process) and then they tested just fine. I
assume I recharged the gates so all was then well.

John :-#)#

I will need to erase the EPROMs before they get new programs. My
wife has a UV light source she uses for curing some sort of fingernail
coating for artificial nails. I'm hoping it will work OK.
The programmer I am buying is the MCUmall Electronics model GQ-4x4.
I called them and they said programmer software verifies the info
downloaded from the EPROM and then once again verifies the uploaded
info.
Eric

 

[John Robertson]

On 2019/11/15 12:01 p.m., etpm@whidbey.com wrote:

On Fri, 15 Nov 2019 11:27:05 -0800, John Robertson <spam@flippers.com
wrote:

On 2019/11/15 10:56 a.m., Ron D. wrote:
The EProms can cause issues when they age.

From my days of programming the 2716's. My programmer was semi-manual and it was really sensitive to the the programming voltage.

An EEprom may not have been erased completely.

Do inspect the board for bad solder joints.

Freeze spray can sometimes help make equipment fail or work. On a non-powered board, it can help highlight a bad solder joint.


My Xeltek 610P programmer has a feature where it will test EPROMs at +/-
10% of the voltage to help weed out iffy burns or EPROMs.

Recently I had some EPROMs I was verifying and they failed the
over-voltage test - so I reprogrammed them (not erased, just hit them
with the programmer burn process) and then they tested just fine. I
assume I recharged the gates so all was then well.

John :-#)#
I will need to erase the EPROMs before they get new programs. My
wife has a UV light source she uses for curing some sort of fingernail
coating for artificial nails. I'm hoping it will work OK.
The programmer I am buying is the MCUmall Electronics model GQ-4x4.
I called them and they said programmer software verifies the info
downloaded from the EPROM and then once again verifies the uploaded
info.
Eric

I would HIGHLY recommend that you keep the original EPROMs and get some
good 2716s to burn and a few spares...

Please do not erase your originals!

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

 

On Fri, 15 Nov 2019 12:38:19 -0800, John Robertson <spam@flippers.com>
wrote:

On 2019/11/15 12:01 p.m., etpm@whidbey.com wrote:
On Fri, 15 Nov 2019 11:27:05 -0800, John Robertson <spam@flippers.com
wrote:

On 2019/11/15 10:56 a.m., Ron D. wrote:
The EProms can cause issues when they age.

From my days of programming the 2716's. My programmer was semi-manual and it was really sensitive to the the programming voltage.

An EEprom may not have been erased completely.

Do inspect the board for bad solder joints.

Freeze spray can sometimes help make equipment fail or work. On a non-powered board, it can help highlight a bad solder joint.


My Xeltek 610P programmer has a feature where it will test EPROMs at +/-
10% of the voltage to help weed out iffy burns or EPROMs.

Recently I had some EPROMs I was verifying and they failed the
over-voltage test - so I reprogrammed them (not erased, just hit them
with the programmer burn process) and then they tested just fine. I
assume I recharged the gates so all was then well.

John :-#)#
I will need to erase the EPROMs before they get new programs. My
wife has a UV light source she uses for curing some sort of fingernail
coating for artificial nails. I'm hoping it will work OK.
The programmer I am buying is the MCUmall Electronics model GQ-4x4.
I called them and they said programmer software verifies the info
downloaded from the EPROM and then once again verifies the uploaded
info.
Eric


I would HIGHLY recommend that you keep the original EPROMs and get some
good 2716s to burn and a few spares...

Please do not erase your originals!

John :-#)#

I will NOT be erasing the originals. They are, as near as I can tell,
not available from any soyrce. I have looked for a long time on eBay
in the hope that someone scrapping a machine will have some. But the
machines, while similar, are never the same. I'm even afriad to copy
them. That's why I am going to practice on some others first.
Eric

 

[John Robertson]

On 2019/11/15 12:47 p.m., etpm@whidbey.com wrote:

On Fri, 15 Nov 2019 12:38:19 -0800, John Robertson <spam@flippers.com
wrote:

On 2019/11/15 12:01 p.m., etpm@whidbey.com wrote:
On Fri, 15 Nov 2019 11:27:05 -0800, John Robertson <spam@flippers.com
wrote:

On 2019/11/15 10:56 a.m., Ron D. wrote:
The EProms can cause issues when they age.

From my days of programming the 2716's. My programmer was semi-manual and it was really sensitive to the the programming voltage.

An EEprom may not have been erased completely.

Do inspect the board for bad solder joints.

Freeze spray can sometimes help make equipment fail or work. On a non-powered board, it can help highlight a bad solder joint.


My Xeltek 610P programmer has a feature where it will test EPROMs at +/-
10% of the voltage to help weed out iffy burns or EPROMs.

Recently I had some EPROMs I was verifying and they failed the
over-voltage test - so I reprogrammed them (not erased, just hit them
with the programmer burn process) and then they tested just fine. I
assume I recharged the gates so all was then well.

John :-#)#
I will need to erase the EPROMs before they get new programs. My
wife has a UV light source she uses for curing some sort of fingernail
coating for artificial nails. I'm hoping it will work OK.
The programmer I am buying is the MCUmall Electronics model GQ-4x4.
I called them and they said programmer software verifies the info
downloaded from the EPROM and then once again verifies the uploaded
info.
Eric


I would HIGHLY recommend that you keep the original EPROMs and get some
good 2716s to burn and a few spares...

Please do not erase your originals!

John :-#)#
I will NOT be erasing the originals. They are, as near as I can tell,
not available from any soyrce. I have looked for a long time on eBay
in the hope that someone scrapping a machine will have some. But the
machines, while similar, are never the same. I'm even afriad to copy
them. That's why I am going to practice on some others first.
Eric

Reading is pretty safe, however I would recommend you contact MCUmall
and make sure that the READ process for pin 21 is done at 5VDC and not
at the programming voltage which is 21VDC. You can verify this with a
voltmeter by simply not having any chip in the socket and then do a read
while monitoring socket pin 21 (ad common at pin 12) to make sure the
voltage is 5VDC. It would not hurt to verify that pin 24, again relative
to pin 12 - is also 5VDC. Lastly, for the paranoid folks, I would also
check pin 20 and 18 to make sure they are never higher than 5VDC.

I am not saying the MCUmall programmer is bad, I'm just pointing out how
I would check any programmer that I am trusting irreplaceable EPROMs to!

If you have a scope so much the better to test the programmer READ
voltages at the various pins!

As you say you only have the one set of EPROMs and your equipment would
be worthless if any are damaged by the programmer!

Does this machine have an 8-bit CPU such as Z80, 68XX, 6502, etc? If
someone lives near you and has a Fluke 9010 with the appropriate pod
then they could extract the data from the EPROMs at no risk to them.
They would also need an RS-232 port on the Fluke to grab the data... I
can do this in my shop, but I suspect we are not very close - I'm in
Vancouver (Burnaby, but no one knows that city), Canada area...

John

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