Metalwork - Lathe and Mill topics: October 2025

Tuesday, 28 October 2025

Re: [electronics101] Test Probes Wash 0402 LED strips

There are also tweezer test probes that have tiny metal tips connected to a pair of test leads.

They are convenient for measuring loose SMT parts on the work bench.

There are also tiny “pen-style” capacitance / resistance DMM with built in tweezers.

I use a stereo microscope when working on tiny parts. It works extremely well! My eyes are old too.

Bertho

From: electronics101@groups.io <electronics101@groups.io> On Behalf Of Andy via groups.io
Sent: 28 October, 2025 9:24
To: electronics101@groups.io
Subject: Re: [electronics101] Test Probes Wash 0402 LED strips

For probing 0402 parts, personally I think a small fixture with both probes glued to it, would not be a bad idea. They should be the right spacing for 0402 sized components. I have enough trouble getting one probe in the right place (ancient eyes), so getting two of them to both "stay put" where I want them can be a near impossibility. Having to hold only one fixture with the right probe spacing, helps with that.

I was a little surprised that you could solder to sewing needles, but honestly I never tried it. It might depend on the brand of needle, and the heat of your iron, especially if the needle is clamped in a vise for soldering.

Andy

Re: [electronics101] Test Probes Wash 0402 LED strips

Andy

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Re: [electronics101] Test Probes Wash 0402 LED strips

No question asked by me. I just explained a very good way to make test probes for working on electronics. I soldered the test wire to the eye of the needle using regular 63/37% solder with flux core. Regular flux works fine too.

Keep them very sharp and they will not slip. Very fine sandpaper can be used to sharpen them.

Bertho

From: electronics101@groups.io <electronics101@groups.io> On Behalf Of paul larner via groups.io
Sent: 28 October, 2025 7:19
To: electronics101@groups.io
Subject: Re: [electronics101] Test Probes Wash 0402 LED strips

so is anything being asked here? or am i missing something? or are they statements only?If wou made probes with sewing needles how did you solder the wires onto them and what solder and flux did you use 60/40 leaded and rosin?.

Re: [electronics101] Test Probes Wash 0402 LED strips

On Tue, Oct 28, 2025 at 07:19 AM, paul larner wrote:

so is anything being asked here? or am i missing something? or are they statements only?

I think you might have missed that this was a misplaced "reply" to another message thread about LEDs that were sold in long strips:

https://groups.io/g/electronics101/message/100099

(and its replies).

These homemade sewing needle probes were suggested as a way to probe and test those SMT diodes, but they probably do not help with that. These probes might help if the LEDs were wired in a circuit with insulated wires, such as holiday decoration wire strips in the old days when they used wires.

Andy

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Re: [electronics101] Test Probes Wash 0402 LED strips

so is anything being asked here? or am i missing something? or are they statements only?If wou made probes with sewing meedles how did you solder the wires onto them and what solder and flux did you use 60/40 leaded and rosin?.

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Tuesday, 21 October 2025

[Amateur-repairs] FS: Vintage Most-Often-Needed Radio Service Manuals by Supreme Publications #test-equipment

From an estate, an incomplete collection of Most-Often-Needed Radio Service manuals by Supreme Publications & compiled by M N Beitman. Years range from 1939 to early 1960s. I have multiple copies of some years. The manuals are in good to very good condition but all show age and signs of being stored. All pages appear fully legible and no manual appears to be missing pages. I've organized them by year and photographed the index pages of each year. 33 manuals in total, including a couple of miscelaneous. Overall photos show the range. If interested, please state the year(s) you want. $20 per manual, USPS shipping included. International shipping at an appropriate postage rate. Will sell the entire lot to an interested person; please inquire. The manuals are being advertised across multiple platforms.

Photos here: https://photos.app.goo.gl/Mv2r9oxKVKwvjdqy6.

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Monday, 13 October 2025

Re: [Amateur-repairs] Test Leads

On Monday, October 13, 2025 at 04:48:09 AM PDT, Dino Papas via groups.io <kl0s=cox.net@groups.io> wrote:

Thanks for the sourcing tip on the TMP connectors, didn't know K6IOK had those available...still have to install the TS-940S PA that's sitting in the project queue, so many, so little time!

I hate those connectors, maybe a bit less than UFLs. You can make your own but you have to first find the darn connectors and then build them with RG-174/RG-316 coax, been there, done that. But as you say it's really the only way to I/O with older radios that use them for interconnects.

TNX again, and big TNX for all the work you do for our old Kenwood favorites!

73 - Dino KLØS

Re: [Amateur-repairs] Test Leads

Thanks for the sourcing tip on the TMP connectors, didn't know K6IOK had those available...still have to install the TS-940S PA that's sitting in the project queue, so many, so little time!

TNX again, and big TNX for all the work you do for our old Kenwood favorites!

73 - Dino KLØS

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Sunday, 12 October 2025

Re: [Amateur-repairs] Test Leads

Yes, very true, my statement made is seem like 50 Ohm impedance was an absolute, but it is simply to accomodate the specified input impedance of the test equipment. Most RF test instruments use either 50 or 75 ohm native input impedance simply to accomodate an intended application. Very few amateur techs posses the collection of attenuators and pads to transform an odd impedance to one compatible with their test instrument.

In reality, it depends on the circuit under test. Then again, I find absolute level measurements are seldom critical. I have fount that in most Transceivers, circuit implementation ditcates the native impedance of Internal RF paths between components, so absolute level measurements there are challenging, which is why the Japanese service manuals typically document the internal IF levels in terms of gain in dB from the previous stage or relative to the specified Rx or Tx source input.

Cheers

________________
73's
Dave - KB7JS

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Re: [Amateur-repairs] Test Leads

That may be true if the source impedance and load impedance are both 50 Ohms. However at the very short runs we encounter at the frequencies we usually work with the characteristic impedance of the cable is not relevant. Your typical scope probe proves this. What may be important is the capacitive loading of the cable, which would be lower for 75 or 93 Ohm coax, but those can be problematic for other mostly mechanical reasons.

On Sun, 12 Oct 2025 12:25:24 -0700
"Dave Phillips KB7JS via groups.io" <utahdog=msn.com@groups.io> wrote:

> For RF level measurements, it is important to match the impecance of the test point with the test instrument port. I use a 50 ohm coaxial test leads with dual grabbers on one end, BNC male on the other for direct connection to the test equipment

--

73

-Jim
NU0C

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Re: [Amateur-repairs] Test Leads

Here's a pretty good looking set of test leads for a DMM: https://www.amazon.com/Young-Dance-24-Multimeter-Insulation/dp/B0C288XZM8. I haven't used this particular set, so I can't vouch for their quality, but they look good and the specs are good. I have a set that looks like this that came with my Agilent handheld DMM. I think this would cover most of your needs for your DMM.

I work for a semiconductor manufacturer as an engineering technician. One of my duties is to maintain the test equipment in the labs at our location and to keep an adequate supply of test leads and test jumper on hand. At work, price is not really a problem. At home, I'm quite a bit more conservative about spending money. I usually get the best I can reasonably afford.

73 de AC7EW

Kelly

From: Amateur-repairs@groups.io <Amateur-repairs@groups.io> On Behalf Of jahman via groups.io
Sent: Sunday, 12 October, 2025 12:42
To: Amateur-repairs@groups.io
Subject: Re: [Amateur-repairs] Test Leads

What a great idea! Thanks for sharing!

73 de Andrew/N5ASE

On Sun, Oct 12, 2025 at 4:19 PM maxwelloau via groups.io <maxwelloau=gmail.com@groups.io> wrote:

Tip: Make one of these too. I have made these for 40 or closer to 50years!

Get a felt tipped pen, looks like a normal biro (balltel/pentel or similar) normally constructed with a plugin tip area containing a narrow long felt rod, and a plug in top area keeping the large plastic tube containing the felt wet ink reservoir in place. Use it till it runs dry. Keep them in a jar!
Remove all the felt stuff and throw away.
Use a sewing machine needle, a jeans needle is usually a bit thicker than some, and super glue or araldite this into the pointy tip holder (knock the ball out, drill whatever), drill a hole in the top plug end, size of a silicon 512 strand cable lead (firm fit best).
Assemble silicon lead through a firm top plug hole (got 2 be careful spelling here) and through the body of the pen. Bare some of the silicon wire to stick out the bottom tip area, solder to the flat of the sewing needle (after the glue/araldite dried solid) and push the tip back into the holder. Keep the cap, most important.

Now you have a VERY sharp tipped probe ideal for dense wires and circuitry. I have even gone into the wire insulation itself to make a measurement (only low voltage cabling) to make measurements not available elsewhere.

Ideal for solder pads, IC legs, square IC's, small tabs, etc.

Goes without saying the more tip protruding from the bottom of the pen tip is more prone to snap off (sewing machine needles are brittle) or short stuff!
Of course put the cap on when not in use and that stops getting jabbed later on! Clip top cap onto the silicon wire when probe is in use.

Of course with the inscrutable friends great manufacturing ability and low cost, they now have 4mm banana socket pointy probes and spare probes available too!

Short answer, a lead for each probe ready to go is better than fiddling about with little plugon dodads any day.

Happy probing.

Re: [Amateur-repairs] Test Leads

I have done much the same. I have made RF probes, capacitor isolated probes, and inductive probes doing this. Apparently, if you use industrial sewing needles, they aren't as brittle and will last much longer, however, I generally use whatever my wife has available. The really fine needles are great for SMT probing.

73, Clint, VE3CMQ

From: Amateur-repairs@groups.io <Amateur-repairs@groups.io> On Behalf Of maxwelloau via groups.io
Sent: Sunday, 12 October 2025 14:20
To: Amateur-repairs@groups.io
Subject: Re: [Amateur-repairs] Test Leads

Tip: Make one of these too. I have made these for 40 or closer to 50years!

Get a felt tipped pen, looks like a normal biro (balltel/pentel or similar) normally constructed with a plugin tip area containing a narrow long felt rod, and a plug in top area keeping the large plastic tube containing the felt wet ink reservoir in place. Use it till it runs dry. Keep them in a jar!

Remove all the felt stuff and throw away.

Use a sewing machine needle, a jeans needle is usually a bit thicker than some, and super glue or araldite this into the pointy tip holder (knock the ball out, drill whatever), drill a hole in the top plug end, size of a silicon 512 strand cable lead (firm fit best).

Assemble silicon lead through a firm top plug hole (got 2 be careful spelling here) and through the body of the pen. Bare some of the silicon wire to stick out the bottom tip area, solder to the flat of the sewing needle (after the glue/araldite dried solid) and push the tip back into the holder. Keep the cap, most important.

Now you have a VERY sharp tipped probe ideal for dense wires and circuitry. I have even gone into the wire insulation itself to make a measurement (only low voltage cabling) to make measurements not available elsewhere.

Ideal for solder pads, IC legs, square IC's, small tabs, etc.

Goes without saying the more tip protruding from the bottom of the pen tip is more prone to snap off (sewing machine needles are brittle) or short stuff!

Of course put the cap on when not in use and that stops getting jabbed later on! Clip top cap onto the silicon wire when probe is in use.

Of course with the inscrutable friends great manufacturing ability and low cost, they now have 4mm banana socket pointy probes and spare probes available too!

Short answer, a lead for each probe ready to go is better than fiddling about with little plugon dodads any day.

Happy probing.

Re: [Amateur-repairs] Test Leads

What a great idea! Thanks for sharing!

73 de Andrew/N5ASE

On Sun, Oct 12, 2025 at 4:19 PM maxwelloau via groups.io <maxwelloau=gmail.com@groups.io> wrote:

Tip: Make one of these too. I have made these for 40 or closer to 50years!

Get a felt tipped pen, looks like a normal biro (balltel/pentel or similar) normally constructed with a plugin tip area containing a narrow long felt rod, and a plug in top area keeping the large plastic tube containing the felt wet ink reservoir in place. Use it till it runs dry. Keep them in a jar!

Remove all the felt stuff and throw away.

Use a sewing machine needle, a jeans needle is usually a bit thicker than some, and super glue or araldite this into the pointy tip holder (knock the ball out, drill whatever), drill a hole in the top plug end, size of a silicon 512 strand cable lead (firm fit best).

Assemble silicon lead through a firm top plug hole (got 2 be careful spelling here) and through the body of the pen. Bare some of the silicon wire to stick out the bottom tip area, solder to the flat of the sewing needle (after the glue/araldite dried solid) and push the tip back into the holder. Keep the cap, most important.

Now you have a VERY sharp tipped probe ideal for dense wires and circuitry. I have even gone into the wire insulation itself to make a measurement (only low voltage cabling) to make measurements not available elsewhere.

Ideal for solder pads, IC legs, square IC's, small tabs, etc.

Goes without saying the more tip protruding from the bottom of the pen tip is more prone to snap off (sewing machine needles are brittle) or short stuff!

Of course put the cap on when not in use and that stops getting jabbed later on! Clip top cap onto the silicon wire when probe is in use.

Of course with the inscrutable friends great manufacturing ability and low cost, they now have 4mm banana socket pointy probes and spare probes available too!

Short answer, a lead for each probe ready to go is better than fiddling about with little plugon dodads any day.

Happy probing.

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Re: [Amateur-repairs] Test Leads

Thank you. After doing a little more research I was kind of leaning in that direction.

On 10/12/2025 12:26 PM, Mike N2MS via groups.io wrote:

I have a set of Military surplus screw on test leads and I would not recommend them. The tips come loose resulting in intermittent connections. I now use dedicated test lead sets with fixed tips so I always have a secure connection.

Mike N2MS

On 10/12/2025 2:42 PM EDT K2KKB Gary via groups.io <k2kkb=proton.me@groups.io> wrote:

It is time for me to replace/make new test probes for some of my equipment as well as a newly purchased Tektronix 503 bay, in nearly pristine condition, with DMM, frequency counter, and function generator.

I did not see this addressed in previous discussions so I'll ask it here.

As I'm am relatively new to ham radio repair and not in a commercial set-up, I have been considering test leads with interchangeable tips to help keep the clutter down from a multitude of test probes. My question is: does anyone use this type of test probe? It seems as though the only choices are banana clips or screw-on. I'm curious about any adverse effects of the banana style (and my preference would be the screw-on but I'm also concerned about the availability of the replacement tips). Or, would I be better off to go ahead and have dedicated leads for each job/project?

--   Gary H White K2KKB  Webmaster K7JEP.ORG

Re: [Amateur-repairs] Test Leads

I have a set of Military surplus screw on test leads and I would not recommend them. The tips come loose resulting in intermittent connections. I now use dedicated test lead sets with fixed tips so I always have a secure connection.

Mike N2MS

On 10/12/2025 2:42 PM EDT K2KKB Gary via groups.io <k2kkb=proton.me@groups.io> wrote:

It is time for me to replace/make new test probes for some of my equipment as well as a newly purchased Tektronix 503 bay, in nearly pristine condition, with DMM, frequency counter, and function generator.

I did not see this addressed in previous discussions so I'll ask it here.

As I'm am relatively new to ham radio repair and not in a commercial set-up, I have been considering test leads with interchangeable tips to help keep the clutter down from a multitude of test probes. My question is: does anyone use this type of test probe? It seems as though the only choices are banana clips or screw-on. I'm curious about any adverse effects of the banana style (and my preference would be the screw-on but I'm also concerned about the availability of the replacement tips). Or, would I be better off to go ahead and have dedicated leads for each job/project?

Re: [Amateur-repairs] Test Leads

Gary

The most useful test probe for general troubleshooting is a standard O-Scope probe. Granted, their native impedance, 1M or 10M, can induce attenuation of RF signals, but in most cases, this is not a significant problem as accurate measurement of the RF level is not necessary, you are simply trying to verify its existence or adjust it for max amplitude. The flexibility of an O-Scope probe gives you a clip on grabber, or you can remove that and use the pointed tip. It also affords a close parallel ground terminal that will help significantly in reducing induced RF noise.

For difficult to access test points, I use fine tip grabbers with a wire lead, attach the grabber, clip them to the test point, then attach the scope probe to the wire.

See the following links. You can get a kit with grabbers and leads, from Amazon, very useful, but the clips are a bit fragile.

https://www.amazon.com/BOCEUC-Grabber-Silicone-Analyzer-Electrical/dp/B0BMZD68LJ/ref=sxin_16_pa_sp_search_thematic_sspa

https://www.amazon.com/Goupchn-Breadboard-Flexible-Silicone-Electrical/dp/B08M5GNY47/ref=sr_1_3

https://www.ebay.com/itm/116780774317

The gold standard are grabbers manufactured by Tektronix and HP, but they tend to be available only in quantity to support logic analysis and are typically pricey. Still, well worth having in your test bench kit.

https://www.ebay.com/itm/296267591009

https://www.ebay.com/itm/116780774317

For RF level measurements, it is important to match the impecance of the test point with the test instrument port. I use a 50 ohm coaxial test leads with dual grabbers on one end, BNC male on the other for direct connection to the test equipment. These are common test leads available from many sources. Most are RG58 coaxial cable, which is a bit stiff, I prefer this one from Pamona Electronics with more flexible RG174.

https://www.digikey.com/en/products/detail/pomona-electronics/5187-K-36/737183

If you find you will be working on Japanese radios produced by Kenwood, Icom, Yaesu, you will find that internal RF signals are often routed via coacial cables terminated with Taiko Denki connectors. These present a challengy for signal monitoring. I used to obtain custom test cables and loose connectors from the RF Connection, the only US based supplier of these now obsolete connectors, but they are no longer in business. Jeff Hilliard, K6IOK, acquired their stock and now provides these test cables. I find these test cables to be indespensible.

https://k6iok.com/products/ols/categories/test-cables

________________
73's
Dave - KB7JS

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Re: [Amateur-repairs] Test Leads

Thank you

On 10/12/2025 12:19 PM, maxwelloau via groups.io wrote:

Tip: Make one of these too. I have made these for 40 or closer to 50years!

Get a felt tipped pen, looks like a normal biro (balltel/pentel or similar) normally constructed with a plugin tip area containing a narrow long felt rod, and a plug in top area keeping the large plastic tube containing the felt wet ink reservoir in place. Use it till it runs dry. Keep them in a jar!

Remove all the felt stuff and throw away.

Use a sewing machine needle, a jeans needle is usually a bit thicker than some, and super glue or araldite this into the pointy tip holder (knock the ball out, drill whatever), drill a hole in the top plug end, size of a silicon 512 strand cable lead (firm fit best).

Assemble silicon lead through a firm top plug hole (got 2 be careful spelling here) and through the body of the pen. Bare some of the silicon wire to stick out the bottom tip area, solder to the flat of the sewing needle (after the glue/araldite dried solid) and push the tip back into the holder. Keep the cap, most important.

Now you have a VERY sharp tipped probe ideal for dense wires and circuitry. I have even gone into the wire insulation itself to make a measurement (only low voltage cabling) to make measurements not available elsewhere.

Ideal for solder pads, IC legs, square IC's, small tabs, etc.

Goes without saying the more tip protruding from the bottom of the pen tip is more prone to snap off (sewing machine needles are brittle) or short stuff!

Of course put the cap on when not in use and that stops getting jabbed later on! Clip top cap onto the silicon wire when probe is in use.

Of course with the inscrutable friends great manufacturing ability and low cost, they now have 4mm banana socket pointy probes and spare probes available too!

Short answer, a lead for each probe ready to go is better than fiddling about with little plugon dodads any day.

Happy probing.

--   Gary H White K2KKB  Webmaster K7JEP.ORG

Re: [Amateur-repairs] Test Leads

Tip: Make one of these too. I have made these for 40 or closer to 50years!

Remove all the felt stuff and throw away.

Ideal for solder pads, IC legs, square IC's, small tabs, etc.

Goes without saying the more tip protruding from the bottom of the pen tip is more prone to snap off (sewing machine needles are brittle) or short stuff!

Of course put the cap on when not in use and that stops getting jabbed later on! Clip top cap onto the silicon wire when probe is in use.

Of course with the inscrutable friends great manufacturing ability and low cost, they now have 4mm banana socket pointy probes and spare probes available too!

Short answer, a lead for each probe ready to go is better than fiddling about with little plugon dodads any day.

Happy probing.

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[Amateur-repairs] Test Leads

It is time for me to replace/make new test probes for some of my equipment as well as a newly purchased Tektronix 503 bay, in nearly pristine condition, with DMM, frequency counter, and function generator.
I did not see this addressed in previous discussions so I'll ask it here.

As I'm am relatively new to ham radio repair and not in a commercial set-up, I have been considering test leads with interchangeable tips to help keep the clutter down from a multitude of test probes. My question is: does anyone use this type of test probe? It seems as though the only choices are banana clips or screw-on. I'm curious about any adverse effects of the banana style (and my preference would be the screw-on but I'm also concerned about the availability of the replacement tips). Or, would I be better off to go ahead and have dedicated leads for each job/project?

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Friday, 10 October 2025

[electronics101] Test Probes Wash 0402 LED strips

Test Probes:

My standard test probes for electronic work are made from old plastic pen cases. I solder on a sewing needle to the test wire and then glue it into the old pen.

I can measure PCB voltage through the insulation. I can measure PCB current by probing along a track with two probes using a good DVM.

I have even measured current in individual IC leads when looking for problems.

I also use skinny test wires since I am not going to measure high current.

The only time I use off-the shelf probes is for AC line problems digging into a fuse panel.

Bertho

From: electronics101@groups.io <electronics101@groups.io> On Behalf Of Andy via groups.io

On Fri, Oct 10, 2025 at 10:32 AM, sdmonaco wrote:

These probes will allow you to test the LEDs with your dvm while still in the packaging.

Point of interest - Those probes are "wire piercing", which presumably helps when the devices have insulated leads or are soldered to circuits that have insulated wires. These do not. They are leadless. The connection points are already exposed, but tiny.

That kind of ultra-thin probe might also be good for probing individual LEDs when they are still in their carrier, but I am no expert on that. 'sdmonaco' suggests that it does.

Probing 0402 parts must be challenging. Steady hands and good eyesight are essential.

Andy