22 Dec
2015
22 Dec
'15
12:50 p.m.
Hi,
I've written up my recent third Apple II repair, this time an Apple IIe.
http://www.classic-computers.org.nz/blog/2015-12-22-appleiIIe-no-video.htm
One interesting aspect of this repair is that piggy-backing a logic chip
helped confirm a faulty one. I'd only ever used this technique with RAM.
I'm sure it only works if the chip has a particular type of fault, but it
worked this time for me.
Terry (Tez)
22 Dec
22 Dec
1:09 p.m.
-----Oorspronkelijk bericht-----
Van: cctalk [mailto:cctalk-bounces at classiccmp.org] Namens Terry Stewart
Verzonden: dinsdag 22 december 2015 21:50
Aan: General Discussion: On-Topic and Off-Topic Posts
Onderwerp: Piggybacking 74LS logic chips to confirm a suspected fault
Hi,
I've written up my recent third Apple II repair, this time an Apple IIe.
http://www.classic-computers.org.nz/blog/2015-12-22-appleiIIe-no-video.htm
One interesting aspect of this repair is that piggy-backing a logic chip helped
confirm a faulty one. I'd only ever used this technique with RAM.
I'm sure it only works if the chip has a particular type of fault, but it worked
this
time for me.
Terry (Tez)
I use a HP 10529A logic comparator on regular basis for fault finding in ttl circuits.
It compares a reference chip with the CUT (Chip under test;) it's a very nice
diagnostic tool.
It's a bit like piggy backing just a little more sophisticated :0
-Rik
1:10 p.m.
It works if the gate is open. But if it is shorted to gnd/vcc, you're in
trouble :)
Enviado do meu Tele-Movel
Em 22/12/2015 19:09, "Rik Bos" <hp-fix at xs4all.nl> escreveu:
-----Oorspronkelijk bericht-----
Van: cctalk [mailto:cctalk-bounces at classiccmp.org] Namens Terry Stewart
Verzonden: dinsdag 22 december 2015 21:50
Aan: General Discussion: On-Topic and Off-Topic Posts
Onderwerp: Piggybacking 74LS logic chips to confirm a suspected fault
Hi,
I've written up my recent third Apple II repair, this time an Apple IIe.
http://www.classic-computers.org.nz/blog/2015-12-22-appleiIIe-no-video.htm
One interesting aspect of this repair is that piggy-backing a logic chip
helped
confirm a faulty one. I'd only ever used this
technique with RAM.
I'm sure it only works if the chip has a particular type of fault, but
it
worked this
time for me.
Terry (Tez)
I use a HP 10529A logic comparator on regular basis for fault finding in
ttl circuits.
It compares a reference chip with the CUT (Chip under test;) it's a very
nice diagnostic tool.
It's a bit like piggy backing just a little more sophisticated :0
-Rik
1:27 p.m.
It works if the gate is open. But if it is shorted to
gnd/vcc, you're in
trouble :)
Yea. In my case the chip was quite cool, so I figured it wasn't shorted
and took the risk. On reflection checking vcc/gnd with a multimeter would
be a more definitive way of checking for a short of that nature.
Tez
On Wed, Dec 23, 2015 at 10:10 AM, Alexandre Souza <
alexandre.tabajara at gmail.com> wrote:
It works if the gate is open. But if it is shorted to
gnd/vcc, you're in
trouble :)
Enviado do meu Tele-Movel
Em 22/12/2015 19:09, "Rik Bos" <hp-fix at xs4all.nl> escreveu:
http://www.classic-computers.org.nz/blog/2015-12-22-appleiIIe-no-video.htm
> -----Oorspronkelijk bericht-----
> Van: cctalk [mailto:cctalk-bounces at classiccmp.org] Namens Terry
Stewart
> Verzonden: dinsdag 22 december 2015 21:50
> Aan: General Discussion: On-Topic and Off-Topic Posts
> Onderwerp: Piggybacking 74LS logic chips to confirm a suspected fault
>
> Hi,
>
> I've written up my recent third Apple II repair, this time an Apple
IIe.
>
> One interesting aspect of this repair is that piggy-backing a logic
chip
helped
confirm a faulty one. I'd only ever used this
technique with RAM.
I'm sure it only works if the chip has a particular type of fault, but
it
worked this
time for me.
Terry (Tez)
I use a HP 10529A logic comparator on regular basis for fault finding in
ttl circuits.
It compares a reference chip with the CUT (Chip under test;) it's a very
nice diagnostic tool.
It's a bit like piggy backing just a little more sophisticated :0
-Rik
1:32 p.m.
Becaise they have diodes to gnd/vcc. And the common failure of a diode is a
rupture of the barrier and so, it gets shorted. So the gate is shorted to
ground or vcc
Enviado do meu Tele-Movel
Em 22/12/2015 19:29, "Chuck Guzis" <cclist at sydex.com> escreveu:
On 12/22/2015 01:10 PM, Alexandre Souza wrote:
It works if the gate is open. But if it is
shorted to gnd/vcc, you're
in trouble :)
In my experience, this is the case with a lot of 4000-series CMOS. Don't
exactly understand why.
--Chuck
1:43 p.m.
Or it is a mechanical fault due to a package/die bond wire becoming an open circuit.
This could happen to where the wire joins to either the package or the die pad, or
a wire that was fused due to excess current. Hard to tell unless you decap the
package.
On 12/22/2015 1:32 PM, Alexandre Souza wrote:
Becaise they have diodes to gnd/vcc. And the common
failure of a diode is a
rupture of the barrier and so, it gets shorted. So the gate is shorted to
ground or vcc
Enviado do meu Tele-Movel
Em 22/12/2015 19:29, "Chuck Guzis" <cclist at sydex.com> escreveu:
> On 12/22/2015 01:10 PM, Alexandre Souza wrote:
>
>> It works if the gate is open. But if it is shorted to gnd/vcc, you're
>> in trouble :)
>>
> In my experience, this is the case with a lot of 4000-series CMOS. Don't
> exactly understand why.
>
> --Chuck
>
>
>
>
2:17 p.m.
New subject: Nuts & Volts ESR Meter
FYI, the January 2016 issue of Nuts & Volts magazine has an ESR meter.
It uses a 1ma panel meter, but of course one could substitute a resistor
and use a voltmeter or a multi-meter with a 1ma scale as well.
http://www.nutsvolts.com/magazine
(Though I see the January issue is not there yet).
It also looks like one can get a 3 month complementary subscription via
the URL http://nutsvolts.texterity.com/nutsvolts .
The digital edition is well worth subscribing.
Better yet, if you subscribe for at least 1 year you can be on their
"Preferred Subscriber Network" (no extra charge - just a check-box when
you subscribe) which gives you access to *all* the "digital archived"
(which I found to be PDFs) issues !!
(BTW, Everyday Practical Electronics, EPE, lost me as a subscriber when
they did away with ordinary PDFs and instead have this odd locked thing
with a plug-in. I refuse to subscribe to an online edition of a
magazine where I cannot be assured of permanent access to the issues I
paid for! I don't find their "EPE PDF" version with its plug-in to be
acceptable. I seem to recall that they restricted printing such that
one could not simply print it to a PDF either. Too bad.).
JRJ
7:06 p.m.
New subject: Nuts & Volts ESR Meter
Ok..
On Tue, Dec 22, 2015 at 4:17 PM, Jay Jaeger <cube1 at charter.net> wrote:
FYI, the January 2016 issue of Nuts & Volts
magazine has an ESR
meter. (...)
(Though I see the January issue is not there yet).
So then what's the point of sending the link if the interesting content
isn't actually present?? ;-p
Not trying to be the arse, but seriously..?
7:26 p.m.
New subject: Nuts & Volts ESR Meter
On 12/22/2015 9:06 PM, drlegendre . wrote:
Ok..
On Tue, Dec 22, 2015 at 4:17 PM, Jay Jaeger <cube1 at charter.net> wrote:
Well, I'm VERRRRY Sorry. NOT. Sheesh.
It will, presumably, be there very soon, since I got my paper copy just
yesterday. It isn't like I am connected to the magazine, wrote the
article, or anything like that. I happened to think of it today, and
this week being a celebratory week, I might not get the chance later (or
remember).
Maybe next time I just won't bother. This group is waaaaaaaaayyyyyy to
eager to pick on folks for this or that.
JRJ
FYI, the January 2016 issue of Nuts & Volts
magazine has an ESR
meter. (...)
(Though I see the January issue is not there yet).
So then what's the point of sending the link if the interesting content
isn't actually present?? ;-p
Not trying to be the arse, but seriously..?
7:45 p.m.
New subject: Nuts & Volts ESR Meter
Jay,
I can certainly appreciate your enthusiasm.. but for some reason, I found
it particularly (and oddly) funny that someone would post a link to "Hey,
this really cool thing would be here - if it were, in fact, here - but it
isn't".
Now don't take +me+ so seriously, then, eh? It's all in good humor.
On Tue, Dec 22, 2015 at 9:26 PM, Jay Jaeger <cube1 at charter.net> wrote:
On 12/22/2015 9:06 PM, drlegendre . wrote:
Ok..
On Tue, Dec 22, 2015 at 4:17 PM, Jay Jaeger <cube1 at charter.net> wrote:
Well, I'm VERRRRY Sorry. NOT. Sheesh.
It will, presumably, be there very soon, since I got my paper copy just
yesterday. It isn't like I am connected to the magazine, wrote the
article, or anything like that. I happened to think of it today, and
this week being a celebratory week, I might not get the chance later (or
remember).
Maybe next time I just won't bother. This group is waaaaaaaaayyyyyy to
eager to pick on folks for this or that.
JRJ
FYI, the January 2016 issue of Nuts & Volts
magazine has an ESR
meter. (...)
(Though I see the January issue is not there yet).
So then what's the point of sending the link if the interesting content
isn't actually present?? ;-p
Not trying to be the arse, but seriously..?
23 Dec
23 Dec
4:23 a.m.
New subject: Nuts & Volts ESR Meter
On Tue, Dec 22, 2015 at 10:26 PM, Jay Jaeger <cube1 at charter.net> wrote:
On 12/22/2015 9:06 PM, drlegendre . wrote:
fwiw, Jay, I appreciated your input, followed your link and subscribed,
having never heard of the magazine before.. Looking forward to the Jan.
issue with the ESR meter stuff, which I need for diagnosing my 11/45's
caps. My opinion is that this list is pretty indispensable specifically
for the mentorship that's happening with situations like this. Thank you.
--jake
So then what's the point of sending the link
if the interesting content
isn't actually present?? ;-p
Not trying to be the arse, but seriously..?
Well, I'm VERRRRY Sorry. NOT. Sheesh.
[...]
Maybe next time I just won't bother. This group is waaaaaaaaayyyyyy to
eager to pick on folks for this or that.
5:18 a.m.
New subject: Nuts & Volts ESR Meter
On 23/12/15 12:23, Jacob Ritorto wrote:
fwiw, Jay, I appreciated your input, followed your
link and
subscribed, having never heard of the magazine before.. Looking
forward to the Jan. issue with the ESR meter stuff, which I need for
diagnosing my 11/45's caps. My opinion is that this list is pretty
indispensable specifically for the mentorship that's happening with
situations like this. Thank you. --jake
At $20 for a year for the digital edition, it does look quite good.
However, it says: " *Q: Is Nuts & Volts available in a digital format?*
A: Yes!/Nuts & Volts/Online is an exact replica of the print edition. It
provides the same visual experience, but is delivered and viewed via the
web, using Published Web Format (PWF) technology. It enables readers to
link directly to advertiser information and additional web content
referenced in articles./Nuts & Volts/Online is viewed via the web and is
printable AND downloadable."
Nowhere does it say PDF. I don't want to pay for something that could
vanish, I want something tangible for my $20.
Can someone with the digital edition clarify whether it really is a PDF
or not?
Thanks
Antonio
--
Antonio Carlini
arcarlini at iee.org
6:47 a.m.
New subject: Nuts & Volts ESR Meter
On 12/23/2015 7:18 AM, Antonio Carlini wrote:
On 23/12/15 12:23, Jacob Ritorto wrote:
It is indeed a PDF, with no strings attached. I have been subscribed
for more than 4 years.
JRJ
fwiw, Jay, I appreciated your input, followed
your link and
subscribed, having never heard of the magazine before.. Looking
forward to the Jan. issue with the ESR meter stuff, which I need for
diagnosing my 11/45's caps. My opinion is that this list is pretty
indispensable specifically for the mentorship that's happening with
situations like this. Thank you. --jake
At $20 for a year for the digital edition, it does look quite good.
However, it says: " *Q: Is Nuts & Volts available in a digital format?*
A: Yes!/Nuts & Volts/Online is an exact replica of the print edition. It
provides the same visual experience, but is delivered and viewed via the
web, using Published Web Format (PWF) technology. It enables readers to
link directly to advertiser information and additional web content
referenced in articles./Nuts & Volts/Online is viewed via the web and is
printable AND downloadable."
Nowhere does it say PDF. I don't want to pay for something that could
vanish, I want something tangible for my $20.
Can someone with the digital edition clarify whether it really is a PDF
or not?
Thanks
Antonio
7:48 a.m.
New subject: Nuts & Volts ESR Meter
On 2015-12-23 7:18 AM, Antonio Carlini wrote:
Can someone with the digital edition clarify whether
it really is a PDF
or not?
If you look at the online version, there is a "download" link to the
.PDF in the upper right corner. It downloads and reads just fine.
Thanks Jay!
-Jon
8:13 a.m.
New subject: Nuts & Volts ESR Meter
-----Oorspronkelijk bericht-----
From: Jay Jaeger
Sent: Tuesday, December 22, 2015 11:17 PM
To: cctalk at classiccmp.org
Subject: Nuts & Volts ESR Meter
FYI, the January 2016 issue of Nuts & Volts magazine has an ESR meter.
It uses a 1ma panel meter, but of course one could substitute a resistor
and use a voltmeter or a multi-meter with a 1ma scale as well.
http://www.nutsvolts.com/magazine
(Though I see the January issue is not there yet).
It also looks like one can get a 3 month complementary subscription via
the URL http://nutsvolts.texterity.com/nutsvolts .
The digital edition is well worth subscribing.
Better yet, if you subscribe for at least 1 year you can be on their
"Preferred Subscriber Network" (no extra charge - just a check-box when
you subscribe) which gives you access to *all* the "digital archived"
(which I found to be PDFs) issues !!
(BTW, Everyday Practical Electronics, EPE, lost me as a subscriber when
they did away with ordinary PDFs and instead have this odd locked thing
with a plug-in. I refuse to subscribe to an online edition of a
magazine where I cannot be assured of permanent access to the issues I
paid for! I don't find their "EPE PDF" version with its plug-in to be
acceptable. I seem to recall that they restricted printing such that
one could not simply print it to a PDF either. Too bad.).
JRJ
---------
Thanks for this post Jay.
On the Viperpits forum I received a digital issue (PDF) some 8 months ago.
I remember it was fun reading, even if I was not planning on building it.
Thanks also for the hint "Preferred Subscriber Network" - I checkmarked it!
I subscribed just a few minutes ago. My first issue will be February 2016.
I have not yet checked, but with the "Preferred Subscriber Network",
I hope to have lots of reading stuff during the season's holidays.
Hmmm, as if I had nothing else to do :-/
The list may have a lot of chatter, but the "Delete" key is always within
reach. But your post is exactly one of the reasons to stay aboard!
Thanks Jay!
- Henk
3:37 p.m.
New subject: Nuts & Volts ESR Meter
Thanks all.
I've tried the free subscription for now. That's got me Dec 2015 (which
I can download as a PDF!) and will presumably get me Jan + Feb 2016.
After that I'll probably take out a 1 year subscription and see how it goes.
I'm happy :-)
Antonio
25 Dec
25 Dec
8:22 a.m.
New subject: Nuts & Volts ESR Meter
On 2015-12-23 17:13, Henk Gooijen wrote:
-----Oorspronkelijk bericht----- From: Jay Jaeger
Sent: Tuesday,
December 22, 2015 11:17 PM To: cctalk at classiccmp.org Subject: Nuts &
Volts ESR Meter
FYI, the January 2016 issue of Nuts & Volts magazine has an ESR meter.
It uses a 1ma panel meter, but of course one could substitute a resistor
and use a voltmeter or a multi-meter with a 1ma scale as well.
http://www.nutsvolts.com/magazine
(Though I see the January issue is not there yet).
It also looks like one can get a 3 month complementary subscription via
the URL http://nutsvolts.texterity.com/nutsvolts .
The digital edition is well worth subscribing.
Better yet, if you subscribe for at least 1 year you can be on their
"Preferred Subscriber Network" (no extra charge - just a check-box when
you subscribe) which gives you access to *all* the "digital archived"
(which I found to be PDFs) issues !!
(BTW, Everyday Practical Electronics, EPE, lost me as a subscriber when
they did away with ordinary PDFs and instead have this odd locked thing
with a plug-in. I refuse to subscribe to an online edition of a
magazine where I cannot be assured of permanent access to the issues I
paid for! I don't find their "EPE PDF" version with its plug-in to be
acceptable. I seem to recall that they restricted printing such that
one could not simply print it to a PDF either. Too bad.).
JRJ
---------
Thanks for this post Jay.
On the Viperpits forum I received a digital issue (PDF) some 8 months
ago.
I remember it was fun reading, even if I was not planning on building it.
Thanks also for the hint "Preferred Subscriber Network" - I
checkmarked it!
I subscribed just a few minutes ago. My first issue will be February
2016.
I have not yet checked, but with the "Preferred Subscriber Network",
I hope to have lots of reading stuff during the season's holidays.
Hmmm, as if I had nothing else to do :-/
The list may have a lot of chatter, but the "Delete" key is always within
reach. But your post is exactly one of the reasons to stay aboard!
Thanks Jay!
- Henk
Here is a link to an ESR meter project:
http://ludens.cl/Electron/esr/esr.html
I think Manfred may well be a member here.
A while back I invented my own ESR meter, it is not hard at all.
Essentially an ESR meter is an oscillator which puts out something like
50-100 kHz or so, buffered and divided down to a couple of hundred
millivolts (so that you can measure in-circuit without any PN junctions
conducting and causing errors). That voltage goes across the capacitor
under test, and parallel to the capacitor is a detector which measures
the AC voltage across the capacitor. You then calibrate the meter by
substituting known resistors for the capacitor under test and marking
the dial of the meter appropriately. Manfred's design puts the capacitor
in series with a known resistor instead, making the scale read in the
other direction. There are lots of ESR meter designs on the net.
Jonas
22 Dec
22 Dec
2:16 p.m.
On 22/12/2015 20:50, "Terry Stewart" <terry at webweavers.co.nz> wrote:
Hi,
I've written up my recent third Apple II repair, this time an Apple IIe.
http://www.classic-computers.org.nz/blog/2015-12-22-appleiIIe-no-video.htm
One interesting aspect of this repair is that piggy-backing a logic chip
helped confirm a faulty one. I'd only ever used this technique with RAM.
I'm sure it only works if the chip has a particular type of fault, but it
worked this time for me.
Terry (Tez)
I did this last night with my latest PET-under-repair, in this case an
8032-SK that I bought 15 years ago and am only just getting round to fixing
now. I wasn't getting any display but the video pins LOOKED ok, I could see
the flashing cursor on pin 1 for example. Shortly before giving up for the
night I remembered a post elsewhere that said if the H signal wasn't spot on
20Hz the monitor wouldn't get any HV so I put my logic analyser on the
74LS86 that does the output to the video pins and one pin was stuck low.
Piggybacked another one over the top and I got a display...
--
Adrian/Witchy
Binary Dinosaurs creator/curator
Www.binarydinosaurs.co.uk - the UK's biggest private home computer
collection?
3285
days inactive
3288
days old
18 comments
13 participants
participants (13)
-
a.carlini＠ntlworld.com -
alexandre.tabajara＠gmail.com -
auringer＠tds.net -
cclist＠sydex.com -
cube1＠charter.net -
drlegendre＠gmail.com -
henk.gooijen＠hotmail.com -
hp-fix＠xs4all.nl -
jacob.ritorto＠gmail.com -
jonas＠otter.se -
north＠alum.mit.edu -
terry＠webweavers.co.nz -
witchy＠binarydinosaurs.co.uk