Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Old January 7th 19, 08:32 PM posted to sci.electronics.repair
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Default Calibrated dial knob repair

I recently bought an old Eico 955 In circuit capacitor tester. It worked
right away, but I am going to recap it. But there is a problem. The
Calibrated dial knob wont clamp to the shaft. Someone apparently over
tightened the set screw and cracked the part that fits around the 1/4"
shaft. Someone also must have glued it, then broke it again. That only
makes gluing it again a worse option because the old glue is gooped all
over the pieces, so they wont fit together properly anymore.

Finding a replacement is likely not an option.
Knob Part number - Eico 89678

How would you fix this?

I do have one thought. To carefully grind away the entire center part of
that knob with a dremyl tool. Then take a new smallish knob with a set
screw and drill out the 1/4" hole thru to the face of that knob, and use
JB Weld to glue that new knob inside the old one. Of course the set
screw has to line up with the original set screw hole. (there is room
for a small knob inside). I might even have a solid aluminum knob that
will fit in there, but I have to find them....

However, grinding out that center will be tricky and time consuming,
since the new knob needs to be centered very precisely.


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Old January 7th 19, 09:09 PM posted to sci.electronics.repair
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First recorded activity by DIYBanter: Jun 2017
Posts: 372
Default Calibrated dial knob repair

On Monday, January 7, 2019 at 2:33:24 PM UTC-5, wrote:
I recently bought an old Eico 955 In circuit capacitor tester. It worked
right away, but I am going to recap it. But there is a problem. The
Calibrated dial knob wont clamp to the shaft. Someone apparently over
tightened the set screw and cracked the part that fits around the 1/4"
shaft. Someone also must have glued it, then broke it again. That only
makes gluing it again a worse option because the old glue is gooped all
over the pieces, so they wont fit together properly anymore.

Finding a replacement is likely not an option.
Knob Part number - Eico 89678

How would you fix this?

I do have one thought. To carefully grind away the entire center part of
that knob with a dremyl tool. Then take a new smallish knob with a set
screw and drill out the 1/4" hole thru to the face of that knob, and use
JB Weld to glue that new knob inside the old one. Of course the set
screw has to line up with the original set screw hole. (there is room
for a small knob inside). I might even have a solid aluminum knob that
will fit in there, but I have to find them....

However, grinding out that center will be tricky and time consuming,
since the new knob needs to be centered very precisely.





The knobs all look different, the number of shaft configurations is very limited...
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Old January 7th 19, 11:20 PM posted to sci.electronics.repair
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Posts: 3,918
Default Calibrated dial knob repair

On Mon, 07 Jan 2019 13:32:51 -0600, wrote:

I recently bought an old Eico 955 In circuit capacitor tester. It worked
right away, but I am going to recap it. But there is a problem. The
Calibrated dial knob wont clamp to the shaft. Someone apparently over
tightened the set screw and cracked the part that fits around the 1/4"
shaft. Someone also must have glued it, then broke it again. That only
makes gluing it again a worse option because the old glue is gooped all
over the pieces, so they wont fit together properly anymore.

Finding a replacement is likely not an option.
Knob Part number - Eico 89678

How would you fix this?

I do have one thought. To carefully grind away the entire center part of
that knob with a dremyl tool. Then take a new smallish knob with a set
screw and drill out the 1/4" hole thru to the face of that knob, and use
JB Weld to glue that new knob inside the old one. Of course the set
screw has to line up with the original set screw hole. (there is room
for a small knob inside). I might even have a solid aluminum knob that
will fit in there, but I have to find them....

However, grinding out that center will be tricky and time consuming,
since the new knob needs to be centered very precisely.


A few questions:

1. Which knob?
https://c1.staticflickr.com/4/3834/11055642634_e5daa78fe7_b.jpg

2. What part of the knob is cracked? Is it the plastic part or the
brass center insert? I haven't seen too many knobs without this brass
insert as threading the plastic doesn't last very long on small
diameter knobs.

I'll assume it's the brass insert. These are very much the same for
all similar sized knobs that use a 1/4" dia shaft. I've actually done
what you're proposing. I used a lathe to insure that everything was
centered. Instead of trying to totally drill out the brass insert, I
used a smaller drill (or end mill) that left a thin brass annular
ring. I removed that with a pair of pliers.

The replacement brass insert was provided by a random knob from my
collection. I inserted a 1/4" steel rod into the knob, gouged two
grooves 180 degrees apart in the plastic (being careful to NOT hit the
brass insert), and split open the knob.

Since both the plastic knobs and brass inserts were knurled, there was
no way these were going to fit together without some modification.
After some careful measurement, I put the original knob back into the
lathe, and enlarged the hole slightly so that the new brass insert
would fit. I then roughed up the plastic with sandpaper to give the
glue something to grab onto. I stuffed a grease covered steel (not
brass) screw into the set screw hole, smeared the brass insert with
epoxy, and let it harden. The nylon screw was easily removed, but if
there has been some difficulty, I could easily have removed it with a
little brute force.

Good luck.
--
Jeff Liebermann

150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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Old January 8th 19, 10:44 AM posted to sci.electronics.repair
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Posts: 1,931
Default Calibrated dial knob repair

On Monday, January 7, 2019 at 11:33:24 AM UTC-8, wrote:
I recently bought an old Eico 955 In circuit capacitor tester. ... Someone apparently over
tightened the set screw and cracked the part that fits around the 1/4"
shaft.


A lathe and some aluminum to make a metal fitting, and some creative hollowing-out
of the old knob, can fix it. Old plastic with cracks and glue just won't be a part of
the solution (it needn't look like the original, IMHO).

If the shaft is fully round, consider a lock fitting as used on old trimpots: the
knob can grab that shaft like a collet, but still come off with the right wrenches.


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Old January 10th 19, 03:09 AM posted to sci.electronics.repair
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First recorded activity by DIYBanter: Dec 2018
Posts: 75
Default Calibrated dial knob repair

On Mon, 07 Jan 2019 14:20:44 -0800, Jeff Liebermann
wrote:

On Mon, 07 Jan 2019 13:32:51 -0600, wrote:

I recently bought an old Eico 955 In circuit capacitor tester. It worked
right away, but I am going to recap it. But there is a problem. The
Calibrated dial knob wont clamp to the shaft. Someone apparently over
tightened the set screw and cracked the part that fits around the 1/4"
shaft. Someone also must have glued it, then broke it again. That only
makes gluing it again a worse option because the old glue is gooped all
over the pieces, so they wont fit together properly anymore.

Finding a replacement is likely not an option.
Knob Part number - Eico 89678

How would you fix this?

I do have one thought. To carefully grind away the entire center part of
that knob with a dremyl tool. Then take a new smallish knob with a set
screw and drill out the 1/4" hole thru to the face of that knob, and use
JB Weld to glue that new knob inside the old one. Of course the set
screw has to line up with the original set screw hole. (there is room
for a small knob inside). I might even have a solid aluminum knob that
will fit in there, but I have to find them....

However, grinding out that center will be tricky and time consuming,
since the new knob needs to be centered very precisely.


A few questions:

1. Which knob?
https://c1.staticflickr.com/4/3834/11055642634_e5daa78fe7_b.jpg


The CALIBRATED one with numbers on it.

2. What part of the knob is cracked? Is it the plastic part or the
brass center insert? I haven't seen too many knobs without this brass
insert as threading the plastic doesn't last very long on small
diameter knobs.

No brass parts, the set screw is in plastic, part of the piece that fits
on the 1/4" shaft is broken away (opposite set screw).

I'll assume it's the brass insert. These are very much the same for
all similar sized knobs that use a 1/4" dia shaft. I've actually done
what you're proposing. I used a lathe to insure that everything was
centered. Instead of trying to totally drill out the brass insert, I
used a smaller drill (or end mill) that left a thin brass annular
ring. I removed that with a pair of pliers.


Like I said, there is no brass in it. not the best quality knob in my
opinion..... even if it is 50 years old.........

The replacement brass insert was provided by a random knob from my
collection. I inserted a 1/4" steel rod into the knob, gouged two
grooves 180 degrees apart in the plastic (being careful to NOT hit the
brass insert), and split open the knob.

Since both the plastic knobs and brass inserts were knurled, there was
no way these were going to fit together without some modification.
After some careful measurement, I put the original knob back into the
lathe, and enlarged the hole slightly so that the new brass insert
would fit. I then roughed up the plastic with sandpaper to give the
glue something to grab onto. I stuffed a grease covered steel (not
brass) screw into the set screw hole, smeared the brass insert with
epoxy, and let it harden. The nylon screw was easily removed, but if
there has been some difficulty, I could easily have removed it with a
little brute force.

Good luck.


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Old January 23rd 19, 04:59 PM posted to sci.electronics.repair
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First recorded activity by DIYBanter: Jun 2017
Posts: 372
Default Calibrated dial knob repair

On Wednesday, January 23, 2019 at 1:54:34 AM UTC-5, Jeff Liebermann wrote:

Drivel: The Kidney stones are finally gone after six weeks and three
laser lithotripsy surgeries. Not much pain and no complexications. I
win.

--


Wow, sorry to hear you were afflicted with those *******s. I've had them several times and had one lithotripsy as did my wife (we're fertile I guess). I passed a 6mm stone about three months ago.

Glad you're feeling better; drink more water and don't drink tea!
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Old January 23rd 19, 06:43 PM posted to sci.electronics.repair
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Posts: 3,918
Default Calibrated dial knob repair

On Wed, 23 Jan 2019 07:59:07 -0800 (PST), John-Del
wrote:

On Wednesday, January 23, 2019 at 1:54:34 AM UTC-5, Jeff Liebermann wrote:

Drivel: The Kidney stones are finally gone after six weeks and three
laser lithotripsy surgeries. Not much pain and no complexications. I
win.


Wow, sorry to hear you were afflicted with those *******s. I've had
them several times and had one lithotripsy as did my wife (we're
fertile I guess). I passed a 6mm stone about three months ago.


Medicine has progressed considerably since I had my last stone 10
years ago. These days, the doctors insert a stent (plastic tube)
between the bladder and the affected kidney. This takes the back
pressure off the kidney and therefore eliminated most of the pain. It
was rather painful for about 2 days, until they inserted the stents
(one for each kidney). However, there were some problems breaking up
the stones with the laser and extracting the resulting rubble.

Glad you're feeling better; drink more water and don't drink tea!


Water yes, but your advice about tea is wrong. Most stones are
calcium oxalate. Prior to a few years ago, the recommendation was a
low oxalate diet and low calcium diet. Tea has variable amounts of
oxalate content depending on type. Same with many plant based foods
(kale, spinach, etc). However, the main problem is not oxalates, but
rather calcium. Reducing calcium intake is VERY difficult. I also
have heart problems. Finding a diet that is suitable for both is
difficult or impossible.

Today, the game plan of the year has changed. Instead of reducing
calcium input, calcium rich foods are recommended to reduce kidney
stone production. The idea is to have the calcium bind with the
oxalates in the foods BEFORE the mix gets to the kidneys, where it
gets precipitated as stones. These need to be in the diet, not pills,
and need to have the calcium and oxalate foods eaten at the same time.
For example, adding cheese to the salad.

"Oxalate content and calcium binding capacity of tea and herbal teas."
https://www.ncbi.nlm.nih.gov/pubmed/12495262

What go me was probably high fructose corn syrup, which is beginning
to appear as a cause of kidney stone production:
"The Not-so-Sweet Side of Fructose"
https://jasn.asnjournals.org/content/20/3/457
"Fructose consumption and the risk of kidney stones"
https://www.sciencedirect.com/science/article/pii/S0085253815529517
This was probably my problem as I had increased my consumption of soda
pop over the last 10 years (when I had a previous stone). Oops. I'm
still reading through the literature on the how this allegedly works,
so please do not treat this rant and gospel.

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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Old January 23rd 19, 07:55 PM posted to sci.electronics.repair
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Posts: 372
Default Calibrated dial knob repair

On Wednesday, January 23, 2019 at 12:43:31 PM UTC-5, Jeff Liebermann wrote:
On Wed, 23 Jan 2019 07:59:07 -0800 (PST), John-Del
wrote:

On Wednesday, January 23, 2019 at 1:54:34 AM UTC-5, Jeff Liebermann wrote:

Drivel: The Kidney stones are finally gone after six weeks and three
laser lithotripsy surgeries. Not much pain and no complexications. I
win.


Wow, sorry to hear you were afflicted with those *******s. I've had
them several times and had one lithotripsy as did my wife (we're
fertile I guess). I passed a 6mm stone about three months ago.


Medicine has progressed considerably since I had my last stone 10
years ago. These days, the doctors insert a stent (plastic tube)
between the bladder and the affected kidney. This takes the back
pressure off the kidney and therefore eliminated most of the pain. It
was rather painful for about 2 days, until they inserted the stents
(one for each kidney). However, there were some problems breaking up
the stones with the laser and extracting the resulting rubble.

Glad you're feeling better; drink more water and don't drink tea!


Water yes, but your advice about tea is wrong. Most stones are
calcium oxalate.



I was given the same info by the urologist, but I've found out that just about everyone I spoke to about kidney stones were all big tea drinkers. While tea may not have any calcium oxalate, it may cause some sort of unknown reaction that will somehow foment something in the body that creates stones..

I switched to green tea (black tea is supposedly worse as are dark sodas), have just one cup at night during the winter, and chase it with a glass of water right before bed.



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