Digest for sci.electronics.repair@googlegroups.com - 25 updates in 8 topics

Meanie <meanie@gmail.com>: Dec 21 03:40PM -0500

On 12/21/2016 2:42 PM, Frank Baron wrote:
>> locations.
 
> I think you replied to "Frank" who is different than I am, so you're both
> in agreement that you can get to the edge of the tire tread.
 
You're correct, my apologies.
 
 
Wade Garrett <wade@cooler.net>: Dec 21 11:38AM -0500

On 12/21/16 11:10 AM, Frank Baron wrote:
> Is it that the patch won't hold? Why?
> Is it that the patch will flex too much?
> Or is it that the belts are damaged and they will break?
 
Gotta' ask....what is your ongoing fascination with tire
dismounting/mounting/repairing ;-)
 
--
Make America great again? Hell, I'd be happy if you just made it America
again.
- @KelsowFarlander
Frank <"frank "@frank.net>: Dec 21 01:37PM -0500

On 12/21/2016 12:08 PM, Meanie wrote:
> few mm from the corner and it held up for the remaining tread life.
 
> If the patch/plug job is well prepped and well applied, there shouldn't
> be a reason it will fail.
 
Belts are on the part of the tire that touches the road. Keeps the
tread rigid so it does not flex much on the road and wear faster. Side
wall are made more flexible and are not as easy to patch.
Meanie <meanie@gmail.com>: Dec 21 01:58PM -0500

On 12/21/2016 1:37 PM, Frank wrote:
 
> Belts are on the part of the tire that touches the road. Keeps the
> tread rigid so it does not flex much on the road and wear faster. Side
> wall are made more flexible and are not as easy to patch.
 
I'm very aware of the tire design. That doesn't erase the fact of proper
patching/plugging them. As I stated, your holes aren't even neat the
sidewall. Thus, I'm wondering why you'd even be concerned in those
locations.
Meanie <meanie@gmail.com>: Dec 21 04:22PM -0500

On 12/21/2016 2:31 PM, Frank Baron wrote:
>> be a reason it will fail.
 
> Thanks Meanie, as that was the kind of information I was seeking.
> How close can you get to the edge, and, why.
 
Keep in mind, the industry standard requires patches within right to
left tread area only and never to patch a hole larger than 1/4". Thus, a
repair facility will not usually patch or plug a tire beyond that area.
My experience is just that...mine and I have plugged/patch a few tires
in my days. I've plugged a few tires in my days to help friends and
because service shops will not or just to save a few buck.
 
Overall, it depends on the tire brand as I don't know how much they
differ in design or placement of their belts. I know the more expensive
brands (Bridgestone, Michelin, Pirelli, etc.) have stronger sidewalls
than the cheaper and would benefit a patched hole near the edge. Also,
low profile tires have shorter sidewalls and offer greater strength over
higher sidewall tires.
 
 
> I am assuming it flexes more at the edges.
> I am assuming that flex will eventually work the patch free.
 
Yes, they will flex at the edge and down the sidewall but the tread
portion remains in contact with the road. IMO, a plug or patch anywhere
along the tread area should hold if prepped properly.
> http://i.cubeupload.com/35mRC3.jpg
 
> Although, when I buffed it with the wire wheel, it was flush:
> http://i.cubeupload.com/ZoudZU.jpg
 
A patch roughly 1" to 1 1/4" in diameter is sufficient but I also
recommend a patch/plug combo if one can be used. Otherwise, it is
important to ensure that proper prep is performed.
 
In the areas you plugged, if you're just using a plug, there is no need
to remove the tire, You can simply plug the hole from the outside.
There's no need to cut the plug on the inside. But in those open areas,
a patch/plug is better.
http://i.ebayimg.com/00/s/MzgyWDUwMA==/$T2eC16VHJGYE9nooiLK+BQUlyRvG4Q~~60_57.JPG?set_id=8800005007
if you want to ensure a good seal. You protrude the plug from the inside
out. The patch makes contact with the inner tire and the plug sticks out
from the tread. That is where you cut using a pair of dykes.
http://cdn.mscdirect.com/global/images/ProductImages/5727864-24.jpg
You don't want to cut the plug flush. It is best to leave some
straddling out. As it makes contact with the road, it will help seal the
area from the outside. Even if the hole is inside a tread, cut if flush
with the top of the tread. As the tire wears, so will the plug stem.
Frank Baron <frankbaron@example.com>: Dec 21 04:10PM

How do I decide if these five tires are holed too close to the sidewall?
http://i.cubeupload.com/qD9rZv.jpg
 
Yesterday, for practice in dismounting, patching, and remounting, I patched
these 5 tires above, which a friend and I had lying around.
http://i.cubeupload.com/gCNODb.jpg
 
For the purpose of this thread, we can ignore the tread wear since the
question is being asked about how to decide when a nail hole is too close
to the sidewall.
http://i.cubeupload.com/0X8NfQ.jpg
 
I guess the first question is *WHY* we can't patch next to the sidewall.
Is it that the patch won't hold? Why?
Is it that the patch will flex too much?
Or is it that the belts are damaged and they will break?
Frank Baron <frankbaron@example.com>: Dec 21 06:34PM

On Wed, 21 Dec 2016 10:14:36 -0600, dpb advised:
>> Or is it that the belts are damaged and they will break?
 
> All of the above in greater/lesser degree depending on just where and
> how bad the damage is...
 
Thank you for the information as some were on the last tread groove (see
below how we patched it with a home-made plug patch.
 
> None of those are even close to the sidewall; they're all well out in
> tread area.
 
Thank you for that advice because I wasn't sure at all how close you can
get to the sidewall for it to fail the patch test.
 
We patched this alloy-wheel 55-series tire where a flat-on-both-sides tiny
bolt (with no sharp edges whatsoever) had wedged itself into the last
groove, and eventually punctured the tire.
http://i.cubeupload.com/09PwHs.jpg
 
Here you see the tiny (now headless) bolt next to the puncture hole:
http://i.cubeupload.com/6F0CnI.jpg
 
To properly patch that hole, we reamed the hole with this hand tool:
http://i.cubeupload.com/sZ6qxo.jpg
 
Using that hand tool, we probed the hole slant (it went in straight):
http://i.cubeupload.com/UxYLNx.jpg
 
Then we grabbed this second hand tool & slobbered glue on the plug:
http://i.cubeupload.com/EMU9zy.jpg
 
This is the plug sticking up on the outside of the 55-series tire:
http://i.cubeupload.com/V1dCGA.jpg
 
To cut off the protruding plug, we failed trying the diagonal cutter:
http://i.cubeupload.com/ra3Prp.jpg
 
We also failed with the flush dikes because the plug was too rubbery:
http://i.cubeupload.com/M2BHaA.jpg
 
We ended up slicing it off with a utility knife but we learned how to slice
the plug off more neatly when we cut off the plug protruding on the inside:
http://i.cubeupload.com/r0n5WI.jpg
 
The dremel tool metal blade cut off the plug flush with the inside wall:
http://i.cubeupload.com/QSBXAK.jpg
 
Then we buffed with a wire wheel, where we learned that it would be much
nicer to have a "ball" shaped wire wheel because of the angles involved in
buffing away the outside rubber to expose the virgin rubber to the
vulcanizing glue:
http://i.cubeupload.com/QNrRco.jpg
 
Here is the buffed result before applying the patch over the plug:
http://i.cubeupload.com/otho8w.jpg
 
After applying vulcanizing glue, we stitched down the patch:
http://i.cubeupload.com/BrkYl3.jpg
 
Where this is what the final patch looked like:
http://i.cubeupload.com/UBOmyw.jpg
 
Any advice you can provide will be helpful as the whole point was to learn
by doing, where already I'd do it differently the next time (e.g., I'd use
the dremel tool on both the inside and outside and I would get a roundish
wire brush that fit the inside of a tire better.
Frank Baron <frankbaron@example.com>: Dec 21 07:42PM

On Wed, 21 Dec 2016 13:58:01 -0500, Meanie advised:
 
> patching/plugging them. As I stated, your holes aren't even neat the
> sidewall. Thus, I'm wondering why you'd even be concerned in those
> locations.
 
I think you replied to "Frank" who is different than I am, so you're both
in agreement that you can get to the edge of the tire tread.
 
As I replied to Frank, I hadn't realized there were circumferential steel
belts on top of radial nylon plies, so, it seems (but I'm not sure) that
the delineation line is the edge of the steel belts.
http://www.tirefailures.com/images/tire-tread-diagram.jpg
 
The problem is, of course, figuring out *where* those steel belt edges lie:
http://www.tirefailures.com/images_vf/img/TireCutaway.jpg
 
From the diagrams, they seem to lie just below the last tread marks:
https://www.lesschwab.com/images/backcountry_radialtire_layers.jpg
 
From what you said, the sides that don't have belts flex so much that the
patch would fall off. Is that a correct assessment of the edge problem?
Frank Baron <frankbaron@example.com>: Dec 21 07:42PM

On Wed, 21 Dec 2016 13:37:16 -0500, Frank advised:
 
> Belts are on the part of the tire that touches the road. Keeps the
> tread rigid so it does not flex much on the road and wear faster. Side
> wall are made more flexible and are not as easy to patch.
 
Thanks Frank for explaining as I didn't realize until I just looked it up
that there are circumferential steel "belts" and then there are these
"radial" body plies.
http://www.idmsvcs.com/2vmod/suspension/wheels/tires/beadairleak/tirecutaway.gif
 
If I look at these cutaway diagrams, it seems we can patch to the edge of
the steel belts, but not after that edge (where there is only the "body
plies". Is that right?
https://www.treaddepot.com/assets/images/content/content-atv-construction-1.png
Frank <"frank "@frank.net>: Dec 21 03:17PM -0500

On 12/21/2016 2:42 PM, Frank Baron wrote:
> https://www.lesschwab.com/images/backcountry_radialtire_layers.jpg
 
> From what you said, the sides that don't have belts flex so much that the
> patch would fall off. Is that a correct assessment of the edge problem?
 
That was my point.
Meanie <meanie@gmail.com>: Dec 21 06:25PM -0500

> even if it does not cause loss of control. I've seen fenders (wings to
> our British friends) torn off or totally destroyed by an exploding
> tire belt, and the side of a travel trailer totally demolished.
 
 
I agree about the damage a tire can do
 
Throughout the years, I have often heard warnings such as dropping or
painting a motorcycle helmet halts it's ability to protect, patching or
plugging a motorcycle or car tire is dangerous, etc. and I've have yet
to hear. read or experience any mishaps related from such an event. Not
saying it hasn't happened, but I've yet to hear about such a case. I
won't dispute the possibilities, but I also believe many warnings are in
place for the manufacturer to protect themselves from liability and
warranty. Thus, each person should proceed at their own risk.
 
I have done many repair jobs on car and motorcycle tires to save money
while growing up. I do so now cause I know how even though I can afford
to have it done or replace a product but I cannot see replacing a good
product because it has a minor flaw. Could I be at risk? Possibly, but
it's a risk I've taken often and I'm willing to take again due to the
100% success rate thus far.
Frank Baron <frankbaron@example.com>: Dec 21 11:28PM


> An improperly installed tire repair is a disaster waiting to happen.
> I hope Frankie's liability insurance is adequate and paid
> up.Particularly if the tires are not going on his own vehicle.
 
That's good advice except it's not usable advice unless you actually think
the plug-and-then-patch repairs I made are "a disaster waiting to happen".
 
It's like saying "don't run with scissors", which is great advice, but
essentially not useful advice.
 
What I'm looking for is useful advice, particularly with respect to my
technique. I agree with you that a single-piece patch-plug is superior to
my two piece arrangement but other than that, what do you see "unsafe"
about my plug-and-then-patch method?
 
The whole point is to find out if this method is a safe patch.
 
To help you advise me, I provided plenty of pictures of the plug and then
patch which, I think, is a valid patch [except for the tread wear (which is
a separate issue unrelated to the patch itself)].
 
Here is what is underneath the patch:
http://i.cubeupload.com/ZoudZU.jpg
 
Here is the final repair on the inside (using a big patch):
http://i.cubeupload.com/UBOmyw.jpg
 
Here is the final repair on the inside (using a small patch):
http://i.cubeupload.com/heSWKF.jpg
 
Other than the treadwear, did you see anything unsafe in my patch
technique?
 
a. Location of patch
b. Patch materials
c. Patch technique
 
Or is it all safe?
"Steve W." <csr684@NOTyahoo.com>: Dec 22 01:11AM -0500

Frank Baron wrote:
> my tests so I just wonder what you recommend for two-piece plugs if a
> one-piece patch-plug isn't around.
 
> Would you do it the way I did it, or differently?
 
For practice on techniques the cheap string plugs are good. They will
even work on a good repair as long as you prep the hole correctly.
 
I have a variety of different repair materials depending on the tire and
it's intended use.
 
A mushroom plug gun that works great as a quick plug, and they get used
a lot on lawn, ATV and golf cart tires.
http://www.stopngo.com/
 
Good string plugs -
http://safetyseal.com/index.php
 
combo patch/plugs and boots, plus various other supplies.
http://www.blackjacktirerepair.com/
 
--
Steve W.
"James Wilkinson Sword" <invalid@something.com>: Dec 22 01:57AM

> Is it that the patch won't hold? Why?
> Is it that the patch will flex too much?
> Or is it that the belts are damaged and they will break?
 
They're TYRES. TIRES means run out of energy. Learn basic English.
 
--
The most effective way to remember your wife's birthday is to forget it once.
N_Cook <diverse@tcp.co.uk>: Dec 20 04:11PM

Dropped on hard floor and now just 1/2 second LED illumination.
No sophisticated chippery inside, an LM324 and 2x TL494, no SMD unless
under something.
No obviously failed solder joints of big lumps or elsewhere , no cracked
pcb.
4 IRF740 and 4x RFPN06 and a 7812 complete the main active stuff, what
would be most likely mechanical failure inside? DIP IC, transistor,
diode, other?
N_Cook <diverse@tcp.co.uk>: Dec 21 08:16PM


> those things usually both sides of the output outlet differential relative to chassis ground and they have a kind of ground fault sensor to shut
> the inverter off if there is any significant flow to the ground pin.
 
> m
 
Cracked ferrite of the inverter transformer or AC output RFI filer
torroid with live and neutral turns both around it?
Ralph Mowery <rmowery28146@earthlink.net>: Dec 21 02:51PM -0500

In article <01f5802b-4edd-48e1-9216-80bbb818d031@googlegroups.com>,
makolber@yahoo.com says...
 
> So in each case the answer is ...it depends.
 
> I think it would be a gross exaggeration to say that digital TV is environmentally more friendly compared to analog because of power consumption.
 
> m
 
 
There is another factor also. For the same bandwidth there can be
several low resolution TV 'chanels' on the same ammount of bandwidth as
one analog tv chanel.
boomer#6877250@none.com: Dec 20 01:25AM -0600

On Mon, 12 Dec 2016 10:38:29 -0800, John Robertson <spam@flippers.com>
wrote:
 
>machines that are portable. I take mine home every night for example,
>the rest are left wherever the staff last used them (cable locks).
 
>John :-#)#
 
I used to leave my Thinkpad T43 plugged in all the time. I used the
computer maybe twice a month. I had used it in my car and it was working
fine. I got home, plugged it in, and a gr days later I turned it on. The
computer refused to turn on both with battery and AC power. The power
module was working. I replaced the coin cell in the computer, it still
did not turn on. I tested the hard drive in another computer, that was
fine.
 
I thought about it, and recall we had a bad lightning storm on between
the last time I used the computer and the time it refused to start.
Apparently lightning fryed the motherboard.
 
I'm not equipped to repair this sort of thing, and being an older
computer, I simply bought an identical model on ebay for about $40.
I was able to use the power converter, battery, hard drive, and CD drive
from the old computer in the new one. I did have to reinstall Windows XP
though. Swapping the old HDD simply would not boot. I was told that has
soemthing to do with the activation for XP. But I did not lose any data,
all of that was fine on the old HDD, I just had to copy it to a flash
drive (using another computer), and put it on the new laptop.
 
I wont be leaving my laptops plugged in all the time anymore. Especially
during the seasons when we have electrical storms.
Bruce Esquibel <bje@ripco.com>: Dec 21 11:30AM


> Correct - 53VAC - I linked the clear schematic, while still looking at the
> blurry one.
 
Ok, if this is a "for yourself" repair, I'd do what someone else suggested
and use multiple transformers. At least one for the low current pair and
the oddball for the dual 53V side.
 
One suggestion, you can probably find dual 48V ones without too many
problems, those had to have been used by the telcos for charging their
batteries when everything was copper based.
 
I really think the 5V difference is going to make little change, probably
cut a couple watts off peak output but should be totally safe to use.
 
At least you can see if the rest of it still works and if it does, just
leave it like that while in search of something closer to the original one.
 
-bruce
bje@ripco.com
"Benderthe.evilrobot" <Benderthe.evilrobot@virginmedia.com>: Dec 25 07:04PM

"mike" <ham789@netzero.net> wrote in message
news:o34q50$his$1@dont-email.me...
>> scrounged a better one on Freegle, I'd just like to know what's going on.
 
>> Thanks.
> it's almost always bad caps.
 
Quite possibly - I'd just about summoned the courage to tackle the clutter
around the monitor so I could swap it out, I wanted something to eat so
fired up the PC while I was sitting there - suddenly the monitor was
behaving itself.
 
Other symptoms were starting to emerge; some display aspects were starting
to look washed out - the cursor would lose contrast while editing email
replies.
 
Today its suddenly working normally.
Jeroni Paul <JERONI.PAUL@terra.es>: Dec 25 03:51PM -0800

Benderthe.evilrobot wrote:
> to look washed out - the cursor would lose contrast while editing email
> replies.
 
> Today its suddenly working normally.
 
 
I've found these microswitches leak some sort of oil, probably disintegration of some rubber part inside that turns conductive over time. This together with high impedance inputs causes false button presses.
Frank Baron <frankbaron@example.com>: Dec 25 07:19PM

On Sun, 25 Dec 2016 18:44:58 +0000 (UTC), Frank Baron advised:
 
> http://i.cubeupload.com/WYoC8J.jpg
 
> what specifically do you think they mean by "urging" and "treading"?
> http://i.cubeupload.com/2Bsddp.gif
 
Restating the question to ask if anyone here can tell us what the patent
says about the single-torsion spring setup...
 
The problem everyone with a clutch has on 3rd-generation Toyota 4Runners,
Tacomas, and Tundras is that the Toyota dealer seems blissfully unaware of
the clutch pedal squeak root cause during the warranty period.
http://i.cubeupload.com/62kbRS.jpg
 
So the dealers simply grease the $5 nylon P bushing and delron Q bushings,
but by the time the squeak occurs, the $100 clutch pedal P-tab groove is
already starting to be destroyed, eventually taking with it the $100 clutch
pedal bracket holding the two $5 Q bushings.
http://i.cubeupload.com/eXICt7.jpg
 
So most of us have redesigned the Toyota clutch-pedal return assembly to
remove the extremely complex (geometrically) torsion spring and replace it
with a far simple linear spring setup.
http://i.cubeupload.com/WO7trl.jpg
 
We've also redesigned the P and Q bushings, using better materials:
http://i.cubeupload.com/UMY0Vl.jpg
 
But they still fail within two or three years.
http://i.cubeupload.com/UnuX55.jpg
 
We're currently at the stage of trying to *understand* why Toyota engineers
used such a horrifically complex clutch-pedal-return mechanism, which we
need to know if we're going to assess the long-term impact of our redesign.
http://i.cubeupload.com/Y18Qdh.jpg
 
We only recently found the patent, which shows a mechanism almost exactly
the same as ours, so, at this point, we're just trying to understand the
patent wording with respect to the single-spring function because we have
been re-designing the single spring setup using a variety of methods:
http://i.cubeupload.com/TYHGRW.jpg
 
The reason it matters is that the patent shows both a two-spring and a
single-spring mechanism, where we presume the two-spring mechanism operates
in both directions while we can intuit that the single-spring mechanism
operates only in one direction.
http://i.cubeupload.com/wYA3iD.jpg
 
But is that the case?
 
We don't know, simply because we don't understand the language of the
patent. https://www.google.com/patents/US4907468
 
Do you?
 
Specifically, what is the patent saying the single-spring apparatus
accomplishes?
Frank Baron <frankbaron@example.com>: Dec 25 08:31PM

On Sun, 25 Dec 2016 19:19:15 +0000 (UTC), Frank Baron advised:
 
>> accomplishes?
 
> The "treading force" is the pressure exerted on the pedal,
> and "urging the pedal" means operating it.
 
I wasn't sure if the terms were "directional" since what we're trying to
figure out is why Toyota uses this method, and what the difference is in
the patent description for the two spring method (which we don't have in
our vehicles) and the one spring method (which is what we have).
 
Since our vehicle diagrams look almost exactly like those in the patent, we
think the rationale as to WHY Toyota used such a complex mechanism will be
described in the patent (if we only understood what the patent says).
 
Here is our vehicle diagram:
http://i.cubeupload.com/2Bsddp.gif
 
Here is the patent diagram (which is almost exactly the same):
http://i.cubeupload.com/wYA3iD.jpg
 
While some of us have re-engineered the bushings, the bushings still fail:
http://i.cubeupload.com/8lgaVh.jpg
 
Given the re-engineered bushings still fail, most of us have simply
dispensed with the torsion spring altogether, replacing it with a linear
spring instead:
http://i.cubeupload.com/pSB77I.jpg
 
We've spent some effort on finding just the right geometries for that
linear spring:
http://i.cubeupload.com/FaKA4k.jpg
 
But, we're really shooting blind if we don't know WHY Toyota used such a
complex torsion spring setup when we know they knew all about the linear
springs (since all the attachment points already exist!).
http://i.cubeupload.com/WO7trl.jpg
 
Given what you've said, which is that "urging" is merely operating the
pedal, and "treading" is the force applied, then we can convert this quote:
https://www.google.com/patents/US4907468
 
"The present invention relates to an apparatus for reducing the /treading/
force required to operate a pedal, such as the clutch pedal of an
automobile. More specifically, the present invention relates to an
improvement of the means for /urging/ the pedal."
 
To this quote:
"The present invention relates to an apparatus for reducing the /amount of/
force required to operate a pedal, such as the clutch pedal of an
automobile. More specifically, the present invention relates to an
improvement of the means for /operating/ the pedal [initially]."
 
It's important to get the interpretation correct because the pedal has
multiple modes of travel, from the initial pressure to the ending release
to the various points in the arc in between (which the patent discusses in
similarly cryptic engineering terms).
 
In summary, it seems that the patent mostly refers to the purpose in being
to alleviate STARTING (urging) force - would you concur?
Jeroni Paul <JERONI.PAUL@terra.es>: Dec 25 09:13AM -0800

I have an HP LaserJet 4L that has sit unused for five years, when last used it printed pefectly. Now I get this:
 
http://imgur.com/a/a51D0
 
I tested to open the printer door halfway in the process to see the print before the fuser and the mess is there, so not a fuser problem. In this test I noticed very little toner transferred to the paper, the part of the OPC that had already passed over the paper had the printed image sharp and clean on it, and the toner transferred to the paper was very faint. Could that point to some missing voltage that should have caused the toner to be attracted into the paper?
N_Cook <diverse@tcp.co.uk>: Dec 25 05:33PM

On 25/12/2016 17:13, Jeroni Paul wrote:
> I have an HP LaserJet 4L that has sit unused for five years, when last used it printed pefectly. Now I get this:
 
> http://imgur.com/a/a51D0
 
> I tested to open the printer door halfway in the process to see the print before the fuser and the mess is there, so not a fuser problem. In this test I noticed very little toner transferred to the paper, the part of the OPC that had already passed over the paper had the printed image sharp and clean on it, and the toner transferred to the paper was very faint. Could that point to some missing voltage that should have caused the toner to be attracted into the paper?
 
Damp paper ?, try drying some before using
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