Re: Machinable Potting Material ???
Epoxy resin mixed with enough ground silica to make a stiff paste then rammed into the hole
Robin
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On 19 Aug 2018, at 05:45, ¸é±ð²Ô¨¦±ð <k6fsb.1@...> wrote:
plastic is fairly soft compared to metal, normal thread is 70%, you can use a smaller tap hole to approach 95% thread, use a good sharp tap. plastic threads will hold better and longer with more thread contact.
I have used heli-coil in a few cases. moved to 5-40 or 6-32 in others.
¸é±ð²Ô¨¦±ð
On 2018-08-18 04:27 PM, Bill Riches wrote:
Is the knob large enough to use a 6-32 set screw? If so make sure you use a correct numbered drill with the tap.
73,
Blll, WA2DVU
Cape Mah
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Paul Koretko
Sent: Saturday, August 18, 2018 5:55 PM
To: [email protected]
Subject: [TekScopes] Machinable Potting Material ???
Greetings,
I'm trying to save a couple old plastic knobs that have stripped set screw threads, that don't have brass inserts. I remember reading someplace about a machinable potting material that is easily flowed into a mold. I've tried JB Weld, but it doesn't flow well. It has a tendency to leave void areas. I want to drill a new set screw hole and hand tap it for 4-40 set screw.
I remember seeing some discussion on potting material on one of the groups I read, so I'm asking for help. Any advice will be appreciated. I will also post this to some of the other groups I read.
TNX es 73 de WABAG ..
Paul K.
|
Re: Machinable Potting Material ???
plastic is fairly soft compared to metal, normal thread is 70%, you can use a smaller tap hole to approach 95% thread, use a good sharp tap. plastic threads will hold better and longer with more thread contact.
I have used heli-coil in a few cases. moved to 5-40 or 6-32 in others.
¸é±ð²Ô¨¦±ð
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On 2018-08-18 04:27 PM, Bill Riches wrote: Is the knob large enough to use a 6-32 set screw? If so make sure you use a correct numbered drill with the tap.
73,
Blll, WA2DVU
Cape Mah
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Paul Koretko
Sent: Saturday, August 18, 2018 5:55 PM
To: [email protected]
Subject: [TekScopes] Machinable Potting Material ???
Greetings,
I'm trying to save a couple old plastic knobs that have stripped set screw threads, that don't have brass inserts. I remember reading someplace about a machinable potting material that is easily flowed into a mold. I've tried JB Weld, but it doesn't flow well. It has a tendency to leave void areas. I want to drill a new set screw hole and hand tap it for 4-40 set screw.
I remember seeing some discussion on potting material on one of the groups I read, so I'm asking for help. Any advice will be appreciated. I will also post this to some of the other groups I read.
TNX es 73 de WABAG ..
Paul K.
|
Re: Machinable Potting Material ???
He is wanting to replace stripped inserts in knobs, seems like a great
application for easily tap-able jb weld. No concern about viscosity in that
application.
I'm not sure Micromark's bismuth/tin allow would hold a thread for very
long though.
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On Sat, Aug 18, 2018 at 8:05 PM james morton <JRM38510@...> wrote: Warming the JB Weld will decrease the viscosity. I used to pot solid
state modules for the side-winder AIM_9H using Hysol epoxy, it was done in
a vacum chamber, no voids or bubbles allowed.
On Sat, Aug 18, 2018 at 5:21 PM, Richard L. Wurdack <dickw@...>
wrote:
Micromark has some low-temp casting materials <= 160 degrees F. (Metal)
R.
----- Original Message ----- From: "Mike D" <vfd.ninja@...>
To: <[email protected]>
Sent: Saturday, August 18, 2018 4:16 PM
Subject: Re: [TekScopes] Machinable Potting Material ???
JB weld works well for this.
Mike kd5rjz
On Sat, Aug 18, 2018 at 4:55 PM, Paul Koretko <hglent@...> wrote:
Greetings,
I'm trying to save a couple old plastic knobs that have stripped set
screw
threads, that don't have brass inserts. I remember reading someplace
about
a machinable potting material that is easily flowed into a mold. I've
tried JB Weld, but it doesn't flow well. It has a tendency to leave
void
areas. I want to drill a new set screw hole and hand tap it for 4-40
set
screw.
I remember seeing some discussion on potting material on one of the
groups
I read, so I'm asking for help. Any advice will be appreciated. I
will
also post this to some of the other groups I read.
TNX es 73 de WABAG ..
Paul K.
|
Re: Tektronix 465,NO Trigger
Hello John,
I'm glad you made progress in so little time.
On the tekwiki website, down there is a reference material section and a Tektronix semiconductor design catalog.
Link is here:
There you will find the specs of those FETs,
They are selected matched pairs of 2N4416.
Those are out of production but they're not hard to find.
Ideally, you would need to buy a bunch of them and try to find between them, a pair that are similar to each other and are as close as possible to the target specification.
IIRC, those are selected to have Idss between 10 and 15mA, while the plain 2N4416s are anything between 5 and 15mA.
The voltage offset you're getting is due to the only two last FETs you got working are not matched.
The A level triggering center trimpot is able to compensate for up to 200mV so, you' re at the edge of the cliff but still workable.
Still, with the offset so high, they are so unmatched that they will not track well one to another with changes in temperature.
You may be lucky to find the matched ones at Sphere Research, or Qservice (the latter probably better choice for you as they're in Greece)..
Those are two very well known traders of Tek parts, that many in this group can endorse (me included, for Sphere, I never dealt with Qservice).
Good luck,
Rgrds,
Fabio
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On Sat, Aug 18, 2018 at 06:04 PM, Bert Haskins wrote:
On 8/18/2018 3:49 PM, John Stoole wrote:
Hi Bert
No its not the Tunnel Diodes that are faulty its the Trigger driver JFET's have blown, in fact one of them was cracked which I was unable to see until I
removed the Heatsink, so I hope someone can suggest a substitute
Regards
John
|
Re: Machinable Potting Material ???
An alternate approach would be to hand machine delrin rod on a drill press.
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On Sat, Aug 18, 2018 at 6:05 PM, james morton <jrm38510@...> wrote: Warming the JB Weld will decrease the viscosity. I used to pot solid
state modules for the side-winder AIM_9H using Hysol epoxy, it was done in
a vacum chamber, no voids or bubbles allowed.
On Sat, Aug 18, 2018 at 5:21 PM, Richard L. Wurdack <dickw@...>
wrote:
Micromark has some low-temp casting materials <= 160 degrees F. (Metal)
R.
----- Original Message ----- From: "Mike D" <vfd.ninja@...>
To: <[email protected]>
Sent: Saturday, August 18, 2018 4:16 PM
Subject: Re: [TekScopes] Machinable Potting Material ???
JB weld works well for this.
Mike kd5rjz
On Sat, Aug 18, 2018 at 4:55 PM, Paul Koretko <hglent@...> wrote:
Greetings,
I'm trying to save a couple old plastic knobs that have stripped set
screw
threads, that don't have brass inserts. I remember reading someplace
about
a machinable potting material that is easily flowed into a mold. I've
tried JB Weld, but it doesn't flow well. It has a tendency to leave
void
areas. I want to drill a new set screw hole and hand tap it for 4-40
set
screw.
I remember seeing some discussion on potting material on one of the
groups
I read, so I'm asking for help. Any advice will be appreciated. I will
also post this to some of the other groups I read.
TNX es 73 de WABAG ..
Paul K.
|
Re: Machinable Potting Material ???
Warming the JB Weld will decrease the viscosity. I used to pot solid state modules for the side-winder AIM_9H using Hysol epoxy, it was done in a vacum chamber, no voids or bubbles allowed. On Sat, Aug 18, 2018 at 5:21 PM, Richard L. Wurdack <dickw@...> wrote: Micromark has some low-temp casting materials <= 160 degrees F. (Metal)
R.
----- Original Message ----- From: "Mike D" <vfd.ninja@...>
To: <[email protected]>
Sent: Saturday, August 18, 2018 4:16 PM
Subject: Re: [TekScopes] Machinable Potting Material ???
JB weld works well for this.
Mike kd5rjz
On Sat, Aug 18, 2018 at 4:55 PM, Paul Koretko <hglent@...> wrote:
Greetings,
I'm trying to save a couple old plastic knobs that have stripped set
screw
threads, that don't have brass inserts. I remember reading someplace
about
a machinable potting material that is easily flowed into a mold. I've
tried JB Weld, but it doesn't flow well. It has a tendency to leave void
areas. I want to drill a new set screw hole and hand tap it for 4-40 set
screw.
I remember seeing some discussion on potting material on one of the
groups
I read, so I'm asking for help. Any advice will be appreciated. I will
also post this to some of the other groups I read.
TNX es 73 de WABAG ..
Paul K.
|
Re: TEK 466 Analog Storage
On 2018-08-18 4:16 PM, Paul B. via Groups.Io wrote: Thanks, but that link you provided only seems to point to an extremely high resolution scan of the front cover of the manual (69Mb's worth!) unless there's something I'm doing wrong! It's a multipage TIFF -- most system previewers (Windows, OS X) can page through it. Sorry, I should have warned about that :-) --Toby But no worries, I found another manual/service book quite easily elsewhere and will study that. In the mean time, if anyone knows what the screen should appear like at switch-on (which doesn't seem to be covered in the manual i downloaded) please feel free to chip in here with a description; thanks!
|
Re: Machinable Potting Material ???
Micromark has some low-temp casting materials <= 160 degrees F. (Metal)
R.
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----- Original Message ----- From: "Mike D" <vfd.ninja@...> To: < [email protected]> Sent: Saturday, August 18, 2018 4:16 PM Subject: Re: [TekScopes] Machinable Potting Material ??? JB weld works well for this.
Mike kd5rjz
On Sat, Aug 18, 2018 at 4:55 PM, Paul Koretko <hglent@...> wrote:
Greetings,
I'm trying to save a couple old plastic knobs that have stripped set screw
threads, that don't have brass inserts. I remember reading someplace about
a machinable potting material that is easily flowed into a mold. I've
tried JB Weld, but it doesn't flow well. It has a tendency to leave void
areas. I want to drill a new set screw hole and hand tap it for 4-40 set
screw.
I remember seeing some discussion on potting material on one of the groups
I read, so I'm asking for help. Any advice will be appreciated. I will
also post this to some of the other groups I read.
TNX es 73 de WABAG ..
Paul K.
|
Re: Machinable Potting Material ???
Is the knob large enough to use a 6-32 set screw? If so make sure you use a correct numbered drill with the tap.
73,
Blll, WA2DVU
Cape Mah
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] < [email protected]> On Behalf Of Paul Koretko Sent: Saturday, August 18, 2018 5:55 PM To: [email protected]Subject: [TekScopes] Machinable Potting Material ??? Greetings, I'm trying to save a couple old plastic knobs that have stripped set screw threads, that don't have brass inserts. I remember reading someplace about a machinable potting material that is easily flowed into a mold. I've tried JB Weld, but it doesn't flow well. It has a tendency to leave void areas. I want to drill a new set screw hole and hand tap it for 4-40 set screw. I remember seeing some discussion on potting material on one of the groups I read, so I'm asking for help. Any advice will be appreciated. I will also post this to some of the other groups I read. TNX es 73 de WABAG .. Paul K.
|
Re: Machinable Potting Material ???
JB weld works well for this.
Mike kd5rjz
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On Sat, Aug 18, 2018 at 4:55 PM, Paul Koretko <hglent@...> wrote: Greetings,
I'm trying to save a couple old plastic knobs that have stripped set screw
threads, that don't have brass inserts. I remember reading someplace about
a machinable potting material that is easily flowed into a mold. I've
tried JB Weld, but it doesn't flow well. It has a tendency to leave void
areas. I want to drill a new set screw hole and hand tap it for 4-40 set
screw.
I remember seeing some discussion on potting material on one of the groups
I read, so I'm asking for help. Any advice will be appreciated. I will
also post this to some of the other groups I read.
TNX es 73 de WABAG ..
Paul K.
|
Re: TEK 466 Analog Storage
Just what I was looking for; many thanks.
|
Re: Tek 2467b test 05 error
On Fri, 17 Aug 2018 at 23:01 <Sscandizzo@...> wrote: I'm definitely new to scope repair. But old hand at other electronics repair? The 2467 could not be passed up but it did come with the faults when I
purchased it. I do have an inexpensive digital scope that I hope I can use
to bring this one back to life. Excellent - for the most part you don't need a whole lot'o'scope to diagnose another scope. The power supply ripple is typically measured under the 20MHz bandwidth limiter, and the digital & control signalling on this scope is mostly below 1MHz. The only other instrument you need is a decent DMM (or the like). I'll need a quiet afternoon to open it up. I will check the points you
have mentioned and post my results.
Looking forward to it - good hunting!
|
Machinable Potting Material ???
Greetings,
I'm trying to save a couple old plastic knobs that have stripped set screw threads, that don't have brass inserts. I remember reading someplace about a machinable potting material that is easily flowed into a mold. I've tried JB Weld, but it doesn't flow well. It has a tendency to leave void areas. I want to drill a new set screw hole and hand tap it for 4-40 set screw.
I remember seeing some discussion on potting material on one of the groups I read, so I'm asking for help. Any advice will be appreciated. I will also post this to some of the other groups I read.
TNX es 73 de WABAG ..
Paul K.
|
Re: Tektronix 465,NO Trigger
On 8/18/2018 3:49 PM, John Stoole wrote: Hi Bert
No its not the Tunnel Diodes that are faulty its the Trigger driver JFET's have blown, in fact one of them was cracked which I was unable to see until I removed the Heatsink, so I hope someone can suggest a substitute
Regards
John
mi0dfg If you feel like doing a lot of work, you can look up the part number and cross-reference it to find what else it is used in. Some Tek parts are common and some are made out of unatatium, hope I spelled that right. Are these dual FETs? Bert
On 18 August 2018 at 19:07 Bert Haskins <bhaskins@...> wrote:
On 8/18/2018 1:33 PM, John Stoole wrote:
Well Success at last Fabio !!!!!
I did not realize that the FET's were in sockets under the heatsinks, I decided to change them and I still had no Trigger, as they were out I tested the FETt's on my component tester and there was one faulty on the B TRIG and one on the A TRIG so I used the good ones on Trig A and found that as I turned the Trigger Level control to about 3 o'clock it locked and I had Trigger sync, and the trigger lamp is on. The voltages on the U640 chip 14/15 is 0v but 2/3 is 179 mv I have had a look around and have not found the reason for this ?
Have you any thoughts for a suitable replacement for the FET's?, something I might get locally in UK
We are getting there thanks to you
John
I'm really surprised that no one else has mentioned the infamous tunnel
diode problem.
This often shows up on a lot of the older Tek products and the are many,
many previous discussions on this and other lists.
The problem summery is that as the TDs age their characteristics
change/drift,etc
Some people have managed to obtain replacements that are as good or even
better than the Tek original parts.
This includes me.
I had this on a 465B and some other Tek stuff.
My first solution was to swap the pairs from the B timebase with those
from the A section.
This worked for a few years but course, the B timebase was now bad.
Later I had problems in some 7K units and my good old lugable Cosser scope.
To shorten a very long story, I ended up spending a lot of money on 4,7
and 10 ma. diodes from a ?Russian? ebay seller/s.
I "selected" the trigger diodes using a combination of several test
methods and used the ones that if liked in my 465B.
My 465B now triggers solidly well above 300Mhz.
Now the dirty part is that I have had several old TDs that looked good
on the curve tracer but did not work well in any instrument.
I really don't know the real why of this but my stuff works!.
GOOD LUCK,
Bert
|
Re: TEK 466 Analog Storage
A good start would be to have the controls thus:
POWER Off
INTEN Fully ccw
FOCUS Midrange
SCALE ILLUM As desired
VERT MODE Ch 1
POSITION Midrange
VOLTS/DIV 5V
VAR VOLTS/DIV Calibrated detent
AC-GND-DC DC
INVERT Normal
TRIG VIEW/BANDWIDTH Full bandwidth (No yellow showing)
STORAGE Non Store
TRIGGER (A & B):
COUPLING AC
LEVEL Midrange
SLOPE +
A TRIGGER SOURCE Norm
B (DELAYED) TRIGGER SOURCE Starts after delay
TRIG MODE Auto
A TRIG HOLDOFF Norm
SWEEP (A & B):
HORIZ DISPLAY A
A TIME/DIV 1ms
B TIME/DIV 1ms
VAR TIME/DIV Calibrated detent
DELAY TIME POSITION Full counterclockwise
X10 MAG Off (button out)
Position (Horiz) Midrange
Fine Midrange
Check that the line voltage selector and the Regulating Range Selectors are correctly set for your area.
Pull the power switch on. After about a minute, turn the INTEN control clockwise until you see a horizontal scan. If you can't see this, press the "BEAM FINDER" button and adjust the position controls to roughly centre the display, if you see one. If there's no display at all, you might have any number of faults.
If you connect a probe plugged into the Ch 1 input BNC to a signal source (the CALIBRATOR loop on the rear of the scope will do just fine), you should see a display of the waveform. You might need to increase the VOLTS/DIV setting to see the waveform initially, depending on the amplitude of the applied signal.
A lot of this is taken from the 466 Service Manual, see p 2-11, so RTFM.
E&OE.
Good Luck, Colin.
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-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Paul B. via Groups.Io Sent: 18 August 2018 21:16 To: [email protected]Subject: Re: [TekScopes] TEK 466 Analog Storage Thanks, but that link you provided only seems to point to an extremely high resolution scan of the front cover of the manual (69Mb's worth!) unless there's something I'm doing wrong! But no worries, I found another manual/service book quite easily elsewhere and will study that. In the mean time, if anyone knows what the screen should appear like at switch-on (which doesn't seem to be covered in the manual i downloaded) please feel free to chip in here with a description; thanks!
|
Re: TEK 466 Analog Storage
On Sat, 18 Aug 2018 13:16:06 -0700, you wrote: Thanks, but that link you provided only seems to point to an extremely high resolution scan of the front cover of the manual (69Mb's worth!) unless there's something I'm doing wrong! But no worries, I found another manual/service book quite easily elsewhere and will study that.
In the mean time, if anyone knows what the screen should appear like at switch-on (which doesn't seem to be covered in the manual i downloaded) please feel free to chip in here with a description; thanks! I have a feeling that it depends on whether or not it is in storage mode at startup. With storage mode turned off, IIRC, any storage scope ought to look "normal". In storage mode, then you'll get a screen depending on the type of storage (there are several) and the appropriate controls. Harvey
|
Re: TEK 466 Analog Storage
Thanks, but that link you provided only seems to point to an extremely high resolution scan of the front cover of the manual (69Mb's worth!) unless there's something I'm doing wrong! But no worries, I found another manual/service book quite easily elsewhere and will study that.
In the mean time, if anyone knows what the screen should appear like at switch-on (which doesn't seem to be covered in the manual i downloaded) please feel free to chip in here with a description; thanks!
|
Re: Tektronix 465,NO Trigger
Hi Bert
No its not the Tunnel Diodes that are faulty its the Trigger driver JFET's have blown, in fact one of them was cracked which I was unable to see until I removed the Heatsink, so I hope someone can suggest a substitute
Regards
John
mi0dfg
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Show quoted text
On 18 August 2018 at 19:07 Bert Haskins <bhaskins@...> wrote:
On 8/18/2018 1:33 PM, John Stoole wrote:
Well Success at last Fabio !!!!!
I did not realize that the FET's were in sockets under the heatsinks, I decided to change them and I still had no Trigger, as they were out I tested the FETt's on my component tester and there was one faulty on the B TRIG and one on the A TRIG so I used the good ones on Trig A and found that as I turned the Trigger Level control to about 3 o'clock it locked and I had Trigger sync, and the trigger lamp is on. The voltages on the U640 chip 14/15 is 0v but 2/3 is 179 mv I have had a look around and have not found the reason for this ?
Have you any thoughts for a suitable replacement for the FET's?, something I might get locally in UK
We are getting there thanks to you
John
I'm really surprised that no one else has mentioned the infamous tunnel
diode problem.
This often shows up on a lot of the older Tek products and the are many,
many previous discussions on this and other lists.
The problem summery is that as the TDs age their characteristics
change/drift,etc
Some people have managed to obtain replacements that are as good or even
better than the Tek original parts.
This includes me.
I had this on a 465B and some other Tek stuff.
My first solution was to swap the pairs from the B timebase with those
from the A section.
This worked for a few years but course, the B timebase was now bad.
Later I had problems in some 7K units and my good old lugable Cosser scope.
To shorten a very long story, I ended up spending a lot of money on 4,7
and 10 ma. diodes from a ?Russian? ebay seller/s.
I "selected" the trigger diodes using a combination of several test
methods and used the ones that if liked in my 465B.
My 465B now triggers solidly well above 300Mhz.
Now the dirty part is that I have had several old TDs that looked good
on the curve tracer but did not work well in any instrument.
I really don't know the real why of this but my stuff works!.
GOOD LUCK,
Bert
|
Re: Tektronix 465,NO Trigger
On 8/18/2018 1:33 PM, John Stoole wrote: Well Success at last Fabio !!!!!
I did not realize that the FET's were in sockets under the heatsinks, I decided to change them and I still had no Trigger, as they were out I tested the FETt's on my component tester and there was one faulty on the B TRIG and one on the A TRIG so I used the good ones on Trig A and found that as I turned the Trigger Level control to about 3 o'clock it locked and I had Trigger sync, and the trigger lamp is on. The voltages on the U640 chip 14/15 is 0v but 2/3 is 179 mv I have had a look around and have not found the reason for this ?
Have you any thoughts for a suitable replacement for the FET's?, something I might get locally in UK
We are getting there thanks to you
John
I'm really surprised that no one else has mentioned the infamous tunnel diode problem. This often shows up on a lot of the older Tek products and the are many, many previous discussions on this and other lists. The problem summery is that as the TDs age their characteristics change/drift,etc Some people have managed to obtain replacements that are as good or even better than the Tek original parts. This includes me. I had this on a 465B and some other Tek stuff. My first solution was to swap the pairs from the B timebase with those from the A section. This worked for a few years but course, the B timebase was now bad. Later I had problems in some 7K units and my good old lugable Cosser scope. To shorten a very long story, I ended up spending a lot of money on 4,7 and 10 ma. diodes from a ?Russian? ebay seller/s. I "selected" the trigger diodes using a combination of several test methods and used the ones that if liked in my 465B. My 465B now triggers solidly well above 300Mhz. Now the dirty part is that I have had several old TDs that looked good on the curve tracer but did not work well in any instrument. I really don't know the real why of this? but my stuff works!. GOOD LUCK, ? Bert
|
Re: tektronix 214 option 94
This scope is currently on eBay. If it is of any significance, the probes are permanently wired in, according to the description.
Colin.
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Mike D
Fabio Trevisan
Bill Riches