Metalwork - Lathe and Mill topics: 2024

Friday, 9 August 2024

Re: [electronics101] wife reminded me of the 6/12V test light...

Mine uses a bulb sort of like an AGC fuse, or European dome light, with the terminals on each end.

I suspect it will be less expensive to buy a new one or rig your own using a small 12V bulb.

I just ordered a "probe" with a built in voltmeter, it would be useless for placing in series to measure parasitic load but nice to verify the actual voltage at a test point. With modern cars the difference between 10 and 12V might be enough to be a problme

https://www.mpja.com/Low-Voltage-DC-3-Digit-LED-Meter-Probe-with-Coilcord/productinfo/38380+TE/

The Electronic Goldmine has a lamp 6/12V tester

https://theelectronicgoldmine.com/products/g26432?_pos=9&_sid=1f3082334&_ss=r

I ordered several as 'gag' (but practical) gifts for friends and we have one in each car.

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[electronics101] wife reminded me of the 6/12V test light...

I have one of these testers but the bulb is gone. I searched w/o success for a replacement 'bulb?' Anyone know where I might buy a replacement bulb?

Test Light Automotive, 6V-12V-24V Circuit Tester with Light for Continuity Voltage Electrical Fuse Tester, Car Electric Tester Pen ABS Handle with Sharp Probe&Alligator Clip
and
G26432 - Antique Circuit Tester with 36" Cord for 6V or 12V Car Battery Systems

This one with a red lead . . .

Cen-tech Circuit Tester Set $4.19 w/Coupon 80572744 exp 8/11/24

G.T.

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Tuesday, 23 July 2024

Re: [Amateur-repairs] test

You sending to it now.

Lou WA5LOU

On Tue, Jul 23, 2024 at 11:40 AM Ray W4BYG via groups.io <w4byg=att.net@groups.io> wrote:

Not been able to send to the group this AM. sorry for the bandwidth.
--   "The world is desperate for a faith that combines two things: awestruck sight of unshakable divine Truth, and   utterly practical, round-the-clock power to make a liberating difference in life"... John Piper
Virus-free.www.avg.com

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[Amateur-repairs] test

Not been able to send to the group this AM. sorry for the bandwidth.

--   "The world is desperate for a faith that combines two things: awestruck sight of unshakable divine Truth, and   utterly practical, round-the-clock power to make a liberating difference in life"... John Piper

Virus-free.www.avg.com

Wednesday, 26 June 2024

Re: [Amateur-repairs] Wanted: Bird 43 wattmeter and slugs #test-equipment

have a good one with 10-30, 25-60, and 100-250 MHz slugs...

PG
k3llh@arrl.net

On 6/25/2024 7:24 PM, Ham Radio wrote:

Looking for a working Bird model 43 watt meter and slug to cover 2-30 MHz at 100 watts.

Please DM me if you have such a meter for sale.

Tuesday, 25 June 2024

[Amateur-repairs] Wanted: Bird 43 wattmeter and slugs #test-equipment

Looking for a working Bird model 43 watt meter and slug to cover 2-30 MHz at 100 watts.

Please DM me if you have such a meter for sale.

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Monday, 24 June 2024

[sherline] Laser/Non-Contact Dial test indicator tool?

Any suggestions for an affordable Laser/Non-Contact Dial test indicator tool? I have tried a lot of searches and found nothing. There are a number of laser measuring tools for large distances (100 feet or more) but they only have accuracy to tenths or perhaps hundredths of an inch but not to Thousandths or ten-thousandths that would be desirable for machinist work. There are paint thickness gauges for under $30 that claim to have such resolution so it can be done cheaply. I have done a lot of searches for a laser or contactless measuring tool to replace my mechanical Dial Test Indicator tool but have found nothing. Suggestions wanted!

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Monday, 19 February 2024

Re: [SouthBendLathe] Set Up my 16" - Test Cut

Brilliant! I'd planned to do the two collar test and the 12" long cut test, but I'm going to add this one to the list, probably at the beginning. Still have to mount my chuck, making the back plate this week.

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Sunday, 18 February 2024

Re: [SouthBendLathe] Set Up my 16" - Test Cut

To be clear once I used the 2 1/2 inch bar and skimmed the final coat, over 9 inches I got measurement error. So roughly within 0.00005". That is crazy good for a machine like this.
--
1969 16" x 6' South Bend Lathe
Garage full of old Mopars........

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Re: [SouthBendLathe] Set Up my 16" - Test Cut

Tailstock ram must also be level. You'll find a lot of tailstock bases worn on the front end from heavy handed operators shoving them around. You might have to shim

it level and then you should shim it so the center is .0005"- .001" high.

If you're only out 2/10's of a thou along the length of that bar....that's as good as that machine is going to be. It's not a Hardinge.

Bill

On Sunday, February 18, 2024 at 07:28:24 AM EST, Chips <sakr4360@sbcglobal.net> wrote:

Assuming the twist is out of the bed here's an easy one to set the tailstock.

Say the diameter of the quill in the tailstock is 1.4985 inches.
Turn a short piece of metal in the chuck to that dimension.
Put the tailstock at the far end and lock it down.
Set up a dial indicator in a tool post and zero it on the piece you turned to 1.4985.
Run the carriage down and put the indicator on the tailstock quill. It should read zero.
Now you just tweak the tailstock alignment screws until it reads 0.
You don't need an x feet long bar to work with, just a 1 inch stub of scrapbinium.

Re: [SouthBendLathe] Set Up my 16" - Test Cut

.0002" taper sounds pretty good on a 55 year old machine.

What are you trying to test because your setup has at least 5 variables?

On 2/16/2024 11:00 PM, Mark Z via groups.io wrote:

Having problems with zeroes! Worst is 0.0002" per inch. Missed a zero there too! Its late............. LOL!
--
1969 16" x 6' South Bend Lathe
Garage full of old Mopars........

Re: [SouthBendLathe] Set Up my 16" - Test Cut

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Saturday, 17 February 2024

Re: [SouthBendLathe] Set Up my 16" - Test Cut

THANKS!! that was the Best I've seem!! Figures!! It'd take a meticulous girl

to show us how to get it done!! lol

On Saturday, February 17, 2024 at 10:59:32 AM CST, Rogan Creswick <creswick@gmail.com> wrote:

For aligning a lathe, I use the process Blondihacks describes:

https://youtu.be/H0MwCyWeP7I?si=xxxzUihtQkf_h402

On Sat, Feb 17, 2024, 8:24 AM Mark Z via groups.io <bode528=yahoo.com@groups.io> wrote:

For sure deflection is a problem in the middle so I discarded the numbers that I felt would have been affected. But the number I stated included everything but the actual middle.

In retrospect if I was totally serious about this I would cut a 2 1/2" diameter 18" long piece of aluminum and use it to minimize deflection. Might actually do that at some point. I started the testing by only cutting a 1" wide cut at the ends. Once I was happy with that I did a full cut to get a better profile and eliminate tool position error from the DRO.

What do others do?
--
1969 16" x 6' South Bend Lathe
Garage full of old Mopars........

Re: [SouthBendLathe] Set Up my 16" - Test Cut

Thank you Rogan! That was very helpful in making me understand that I had a brain cramp. I should of know better. My tailstock center alignment was way off and really skewed my numbers.

I redid it with a 12" long 2 1/2" diameter aluminum bar without a center. I did it just at the ends (9 inch measurement difference) and got it to measurement error. I then skimmed the whole 9 inches and did a final cut taking 0.002" off the diameter. Measured every inch over the 9 inches and every measurement was within measurement error (50 millionths of an inch or half a tenth). I am shocked that its is that good.

--
1969 16" x 6' South Bend Lathe
Garage full of old Mopars........

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Re: [SouthBendLathe] Set Up my 16" - Test Cut

For aligning a lathe, I use the process Blondihacks describes:

https://youtu.be/H0MwCyWeP7I?si=xxxzUihtQkf_h402

On Sat, Feb 17, 2024, 8:24 AM Mark Z via groups.io <bode528=yahoo.com@groups.io> wrote:

For sure deflection is a problem in the middle so I discarded the numbers that I felt would have been affected. But the number I stated included everything but the actual middle.

In retrospect if I was totally serious about this I would cut a 2 1/2" diameter 18" long piece of aluminum and use it to minimize deflection. Might actually do that at some point. I started the testing by only cutting a 1" wide cut at the ends. Once I was happy with that I did a full cut to get a better profile and eliminate tool position error from the DRO.

What do others do?
--
1969 16" x 6' South Bend Lathe
Garage full of old Mopars........

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Re: [SouthBendLathe] Set Up my 16" - Test Cut

For sure deflection is a problem in the middle so I discarded the numbers that I felt would have been affected. But the number I stated included everything but the actual middle.

In retrospect if I was totally serious about this I would cut a 2 1/2" diameter 18" long piece of aluminum and use it to minimize deflection. Might actually do that at some point. I started the testing by only cutting a 1" wide cut at the ends. Once I was happy with that I did a full cut to get a better profile and eliminate tool position error from the DRO.

What do others do?
--
1969 16" x 6' South Bend Lathe
Garage full of old Mopars........

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Friday, 16 February 2024

Re: [SouthBendLathe] Set Up my 16" - Test Cut

I'm not a lathe expert or a real machinist, but I'd guess your deviation is in the middle of the cut & likely

from the shaft/work piece flexing. (can't read your measurements on my pc) the guys in the know here

will probably recommend a follow rest.

On Friday, February 16, 2024 at 10:00:55 PM CST, Mark Z via groups.io <bode528=yahoo.com@groups.io> wrote:

Having problems with zeroes! Worst is 0.0002" per inch. Missed a zero there too! Its late............. LOL!
--
1969 16" x 6' South Bend Lathe
Garage full of old Mopars........

Re: [SouthBendLathe] Set Up my 16" - Test Cut

Having problems with zeroes! Worst is 0.0002" per inch. Missed a zero there too! Its late............. LOL!
--
1969 16" x 6' South Bend Lathe
Garage full of old Mopars........

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Re: [SouthBendLathe] Set Up my 16" - Test Cut

Ooops. Over 17" max deviation is 0.0013" Missed a zero.........
--
1969 16" x 6' South Bend Lathe
Garage full of old Mopars........

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[SouthBendLathe] Set Up my 16" - Test Cut

I rebuilt my 1969 16" x 6' lathe some years ago with help from Ted! Thank you Ted! I bought it from work around 1990 - they had bought it new in 1969. But it was not in great shape. Ted provided many new parts and even quite a bit of labor. I had set it up in the old shop and it cut pretty good.

Built a new shop a little over 2 years ago and finally got around to taking a test cut. Started about 0.001" per inch. The worst part is around the chuck area (no surprise) but worst is around 0.002" per inch. But over 17 inches, maximum deviation is 0.013" . From 0 to 17" its 0.0011". I don't know what is typical, but this will work just fine for most of my needs.

What do you typically see from these lathes when in nice shape?

--
1969 16" x 6' South Bend Lathe
Garage full of old Mopars........

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Friday, 2 February 2024

Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

Hello, wow already February and so much to do in retirement! J

I wanted to share something with the group that I found interesting. As I prepare to dig back into my Collins 51S-1 radio, I mentioned that I would start the process over and test all the tubes again. Previously tested on a B&K 747 checker… Since then I have added to my tube checker collection and decided to use my Heathkit TT-1 tester, so I went and validated the calibration again.. Tested a 6V6 and 5Y4 as they were just sitting on the side of my bench and easy to get to. They both checked good!

Then the fun began when I grabbed a 6C4 tube. Being a 7 pin tube it went into a different socket than the 6V6 or 5Y4 tube.

The tube began to act very erratic, On-Off, low then high, testing it for shorts showed no shorts.. At first I suspected a bad tube socket but further inspection showed no issues??? The tube was marked on the box as good with a GM reading of 2150..

So I dug up 4 other 7 pin tubes like a 6BA6, and several others… All checked fine with no problems. Put the 6C4 back in same erratic problem.. My brain began to go in many different directions!!!

So out came my Hickok 6000A, Jackson 658 and Weston 978 Military version it was time to try that 6C4 and see what I get…

6000A said the tube was Good??? But the meter did move a little, like a ¼ of an inch on the needle..

Then I tried the Jackson, and same results, tube was good but again a very small amount of needle movement, like 1/16 of and inch…

!!!!!! Then a big surprise happened, tried it in the Weston 978, same version as the 981 series.. and wow, the tube was acting erratic like it did on the Heathkit TT-1,,, What is going on here??????

So after some coffee and a bit of a rest, we do that at age 76, LOL,, we began to look at some literature in my "How To Use, Calibrate, Repair And Upgrade Tube Testers by Igor S. Popovich" A nice Birthday present and surprise from my son last November…

Their it was in clear print, The Heathkit has a built in 5KHz Oscillators to place signal on the Grid, and the Weston has a 1 KHz oscillator to also place a signal on the tube Grid under test.. Apparently the 6C4 was not happy with this test signal… A good reason why having different tube checkers can help out a lot, or at least one of the Top Testers available…

So I will definitely be using the Heathkit TT-1 with the Weston 978 standing buy when I go back and re-check the tubes in the Collins radio, wonder what I might discover???? I will report back with a follow up, still a few weeks out as I have several other projects now on the bench, like I said Busy in retirement, J

If you have had similar experiences please do share it with the group… Like one of you said early on the only real test for a tube is when it is working in the circuit it was designed for.

Robert WA6PHN,,

What do they sing,, "It Never Rains In Southern California", Sure!!!! L

From: Amateur-repairs@groups.io [mailto:Amateur-repairs@groups.io] On Behalf Of Robert Lonn WA6PHN
Sent: Sunday, January 21, 2024 2:32 PM
To: Amateur-repairs@groups.io
Subject: Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

I will keep this all in mind for sure 👍!!

On Jan 21, 2024, at 1:31 PM, Don Root VA3DRL <drootofallevil@teksavvy.com> wrote:

Robert , that method likely wont to much. I was mainly suggesting that many applications of tubes are not at one bias voltage. Variable Mu tubes are often have the bias controlled by the AVC. For the tube to do its job, it has to work as intended over a wide range of bias voltages/ gains.
Your testers likely test that the tube can provide lots of transcconductance[Gm] [gain, sort-of]. however when the bias is say minus 20 V, they don't bother to do another test the Gm ,, But they do/ can test for gas. It the tube is gassy it mucks-up the tube operation so it cant operate at small gain/ plate current so the tube can't throttle-back to low amplification.
I think I just saw that a 6SK7 has a normal Gm of 5000, but should throttle -back to only 10, [micro-Mhos] I think.
reading back; many 1930's gas tests were not very sensitive, but likely your testers have a good separate gas test using a marked "gas"switch. I wonder if you have tried that on the tube in question?

On Sat, Jan 20, 2024 at 07:56 AM, Robert Lonn WA6PHN wrote:
Not sure about that till I get further into this.. Sometimes I will turn the Bias up and down just to watch how the meter responds.. Not very scientific..
--
73 don va3drl

Sunday, 21 January 2024

Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

I will keep this all in mind for sure 👍!!

On Jan 21, 2024, at 1:31 PM, Don Root VA3DRL <drootofallevil@teksavvy.com> wrote:

Robert , that method likely wont to much. I was mainly suggesting that many applications of tubes are not at one bias voltage. Variable Mu tubes are often have the bias controlled by the AVC. For the tube to do its job, it has to work as intended over a wide range of bias voltages/ gains.
Your testers likely test that the tube can provide lots of transcconductance[Gm] [gain, sort-of]. however when the bias is say minus 20 V, they don't bother to do another test the Gm ,, But they do/ can test for gas. It the tube is gassy it mucks-up the tube operation so it cant operate at small gain/ plate current so the tube can't throttle-back to low amplification.
I think I just saw that a 6SK7 has a normal Gm of 5000, but should throttle -back to only 10, [micro-Mhos] I think.
reading back; many 1930's gas tests were not very sensitive, but likely your testers have a good separate gas test using a marked "gas"switch. I wonder if you have tried that on the tube in question?

On Sat, Jan 20, 2024 at 07:56 AM, Robert Lonn WA6PHN wrote:

Not sure about that till I get further into this.. Sometimes I will turn the Bias up and down just to watch how the meter responds.. Not very scientific..
--
73 don va3drl

Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

Robert , that method likely wont to much. I was mainly suggesting that many applications of tubes are not at one bias voltage. Variable Mu tubes are often have the bias controlled by the AVC. For the tube to do its job, it has to work as intended over a wide range of bias voltages/ gains.
Your testers likely test that the tube can provide lots of transcconductance[Gm] [gain, sort-of]. however when the bias is say minus 20 V, they don't bother to do another test the Gm ,, But they do/ can test for gas. It the tube is gassy it mucks-up the tube operation so it cant operate at small gain/ plate current so the tube can't throttle-back to low amplification.
I think I just saw that a 6SK7 has a normal Gm of 5000, but should throttle -back to only 10, [micro-Mhos] I think.
reading back; many 1930's gas tests were not very sensitive, but likely your testers have a good separate gas test using a marked "gas"switch. I wonder if you have tried that on the tube in question?

On Sat, Jan 20, 2024 at 07:56 AM, Robert Lonn WA6PHN wrote:

Not sure about that till I get further into this.. Sometimes I will turn the Bias up and down just to watch how the meter responds.. Not very scientific..

--
73 don va3drl

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Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

They did this so that there could be a number of different voltages used for the filament voltage for "portable" or mobile use.
You have to be very careful when wiring up the AC cord for Collins or you can easily wire it for the wrong voltage.
Also of note is often with extended use the alignment key on the 11 pin (IIRC) on the socket in the chassis can wear and the plug inserted incorrectly and zip go all of your tubes as well.
The 51S1 was uses extensively by the ASA (Army Security Agency) in the Vietnam era. It was used as a light receiver where the big boat anchors were a little cumbersome. Two were used in helicopters for RDF (and other unspecified uses).
When used with the Collins transmitters of the series they would allow almost full coverage of the range.
All of this is from a very poor memory of way back then.
JD
KE4MD

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Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

Not familiar with it at all, so this is just a guess. But perhaps to create a smaller magnetic filed around the filament leads? 1 amp vs 4 amps means much small magnetic field.

Again, just a guess

Will N4JBD

On 01/21/2024 11:58 AM CST Robert Lonn WA6PHN <roblonn@cox.net> wrote:

Not sure Electrically why Collins did this type of Filament set up, but it must have been for a very sound engineering reason..

This is a link to a short 1 minute Video of the filament circuit and 25.2 Volt AC power transformer. If your familiar as to why this was done this way, it would be appreciated to share your knowledge.. The KWM-2A has a somewhat similar setup for some of its tubes..

Robert WA6PHN

From: Amateur-repairs@groups.io [mailto:Amateur-repairs@groups.io] On Behalf Of Gary WB6OGD
Sent: Friday, January 19, 2024 8:58 AM
To: Amateur-repairs@groups.io
Subject: Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

Robert,
Good advice.
I am no expert but I believe you can't rely too heavily on any tube tester. The actual circuit where the tube goes is the best tester.

I downloaded the 51s1 manual just to have a look. The BFO is one tube. I would try another, there are probably many types that could substitute
there if you don't have a good spare. I am thinking it maybe has a filament to cathode short or leakage of some kind that lets the AC filament signal onto
the BFO signal. But just a guess.
73,
Gary
WB6OGD

Grownups never understand anything by themselves and it is tiresome for children to be always and forever explaining things to them,

Antoine de Saint-Exupery in The Little Prince

Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

Spent an hour going through the 51S-1 Schematic to get myself familiar with the layout again.. Interesting is the 25.2 Volts AC used to feed all the Filaments in the 6 volt tubes.. You basically have 4 tubes in series, with several stages divided with dropping resistors and filter capacitors.. I did get some feedback early last year that someone who had the same issue found a cold soldering connection/Bad Capacitor on one of the filament of a tube..

Not sure Electrically why Collins did this type of Filament set up, but it must have been for a very sound engineering reason..

This is a link to a short 1 minute Video of the filament circuit and 25.2 Volt AC power transformer. If your familiar as to why this was done this way, it would be appreciated to share your knowledge.. The KWM-2A has a somewhat similar setup for some of its tubes..

https://www.youtube.com/watch?v=x4S52RDGNgM

Robert WA6PHN

From: Amateur-repairs@groups.io [mailto:Amateur-repairs@groups.io] On Behalf Of Gary WB6OGD
Sent: Friday, January 19, 2024 8:58 AM
To: Amateur-repairs@groups.io
Subject: Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

Robert,
Good advice.
I am no expert but I believe you can't rely too heavily on any tube tester. The actual circuit where the tube goes is the best tester.

I downloaded the 51s1 manual just to have a look. The BFO is one tube. I would try another, there are probably many types that could substitute
there if you don't have a good spare. I am thinking it maybe has a filament to cathode short or leakage of some kind that lets the AC filament signal onto
the BFO signal. But just a guess.
73,
Gary
WB6OGD

Saturday, 20 January 2024

Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

Not sure about that till I get further into this.. Sometimes I will turn the Bias up and down just to watch how the meter responds.. Not very scientific..

BTW, I was watching a YouTube video on someone restoring a 1960's vintage tube table top AM radio..

He dripped some contact cleaner into the tube socket, OK nothing new there, but then he scrubbed the pin sockets with something??? I could not figure out what he was using?? So I asked him and then the light went off in my head… I think I will use these on the radio just to be sure everything is nice and clean..

Robert WA6PHN

https://www.walmart.com/ip/GUM-Proxabrush-Go-Betweens-Cleaners-Moderate-10-Count/740700598

From: Amateur-repairs@groups.io [mailto:Amateur-repairs@groups.io] On Behalf Of Don Root VA3DRL
Sent: Friday, January 19, 2024 10:53 PM
To: Amateur-repairs@groups.io
Subject: Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

Robert , thanks for your words. I did read your stuff.

If they all test the tube at the same bias and get the same results, that is good.

Do any of them call for testing at a more negative bias as well ?? as a "normal" bias?

From: Amateur-repairs@groups.io [mailto:Amateur-repairs@groups.io] On Behalf Of Robert Lonn WA6PHN
Sent: Friday, January 19, 2024 10:43 PM
To: Amateur-repairs@groups.io
Subject: Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

Don, as I mentioned in my other post, see below, I now have 4 tube testers and they are precision high end devices, hopefully they can expose any tube issues that might come up.. Robert WA6PHN

When I first did this I only had a B&K 747 tube checker, but last year I visited an estate sale and picked up 3 nice tube checkers…

A Heathkit TT-1, A Triplet 3444A and a Hickok 539C.. Good to be the first on site at 6:30am so I could get the pick of the litter.. Also grabbed all the Tubes, probably around 850 or so..

I think I will start with the 539C checker first and if anything seems strange I will check it on a different checker.. The TT-1 was calibrated by me, and it was very close, the 3444 and 539C tracked very close to the calibrated TT-1.. I did replace all the old capacitor in the Hickok and Triplet and a few in the Heathkit..

The Heathkit TT-1 has a built in " I think" a 5 KHz oscillator that they modulate on the grid of the tube.. ???? Maybe I should use that instead of the 539C, may reveal something with a questionable tube.. We will see how all that goes,, Let The FUN BEGIN, after all it is Ham Radio!!! J

From: Amateur-repairs@groups.io [mailto:Amateur-repairs@groups.io] On Behalf Of Don Root VA3DRL
Sent: Friday, January 19, 2024 7:13 PM
To: Amateur-repairs@groups.io
Subject: Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

Robert and all

Re "I am no expert but I believe you can't rely too heavily on any tube tester. "

Well if it "reads bad" it likely is bad.

if it "reads good" it may well be good under the condition it is being tested at.

Most TTs measure Gm [where amplification is part of the intent in the tube.]

If you have a variable Mu tube you really want to know if it works properly with a small bias. But you want it to also work properly at a large negative bias

.. if you don't test it down there you might not know it has too hi a gm .. maybe that is where the gas messes things up like Jacques said.

I recently saw other postings somewhere the front end tube tested ok … but did similar things

.. but we need to get the books out on the details

From: Amateur-repairs@groups.io [mailto:Amateur-repairs@groups.io] On Behalf Of Gary WB6OGD
Sent: Friday, January 19, 2024 11:58 AM
To: Amateur-repairs@groups.io
Subject: Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

--
73 don va3drl

Friday, 19 January 2024

Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

Robert , thanks for your words. I did read your stuff.

If they all test the tube at the same bias and get the same results, that is good.

Do any of them call for testing at a more negative bias as well ?? as a "normal" bias?

Don, as I mentioned in my other post, see below, I now have 4 tube testers and they are precision high end devices, hopefully they can expose any tube issues that might come up.. Robert WA6PHN

When I first did this I only had a B&K 747 tube checker, but last year I visited an estate sale and picked up 3 nice tube checkers…

A Heathkit TT-1, A Triplet 3444A and a Hickok 539C.. Good to be the first on site at 6:30am so I could get the pick of the litter.. Also grabbed all the Tubes, probably around 850 or so..

Robert and all

Re "I am no expert but I believe you can't rely too heavily on any tube tester. "

Well if it "reads bad" it likely is bad.

if it "reads good" it may well be good under the condition it is being tested at.

Most TTs measure Gm [where amplification is part of the intent in the tube.]

If you have a variable Mu tube you really want to know if it works properly with a small bias. But you want it to also work properly at a large negative bias

.. if you don't test it down there you might not know it has too hi a gm .. maybe that is where the gas messes things up like Jacques said.

I recently saw other postings somewhere the front end tube tested ok … but did similar things

.. but we need to get the books out on the details

--
73 don va3drl

Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

Out of the thousands of tubes I have tested, it was a rare occasion I had to go into the circuit to find a bad tube. So unusual I cant remember the last time that happened with me. Very rare!

Lou WA5LOU

On Fri, Jan 19, 2024 at 10:51 PM Jim Shorney <jimNU0C@gmail.com> wrote:

Nevertheless, it remains a fact that a tube can be "good" on a tube tester and fail in circuit, and vise-versa. That is why it is said that the best test of a tube is the circuit that you want it to work in.

73

-Jim
NU0C

On Fri, 19 Jan 2024 22:19:09 -0500
"Lou WA5LOU" <loueverettsr@gmail.com> wrote:

> I've relied on mine for years and years and it has never failed me! I
> could not work on Tube rigs speedily without it!
>
> Lou WA5LOU
>
> On Fri, Jan 19, 2024 at 10:12 PM Don Root VA3DRL <
> drootofallevil@teksavvy.com> wrote:
>
> > Robert and all
> >
> > Re "I am no expert but I believe you can't rely too heavily on any tube
> > tester. "
> >
> >
> >
> > Well if it "reads bad" it likely *is bad. *
> >
> > if it "reads good" it may well be * good *under the condition it is
> > being tested at*. *
> >
> > Most TTs measure Gm [where amplification is part of the intent in the
> > tube.]
> >
> > If you have a variable Mu tube you really want to know if it works
> > properly with a small bias. But you want it to also work properly at a
> > large negative bias
> >
> > .. if you don't test it down there you might not know it has too hi a gm
> > .. maybe that is where the gas messes things up like Jacques said.
> >
> > I recently saw other postings somewhere the front end tube tested ok …
> > but did similar things
> >
> > .. but we need to get the books out on the details
> >
> >
> >
> >
> >
> >
> >
> > *From:* Amateur-repairs@groups.io [mailto:Amateur-repairs@groups.io] *On
> > Behalf Of *Gary WB6OGD
> > *Sent:* Friday, January 19, 2024 11:58 AM
> > *To:* Amateur-repairs@groups.io
> > *Subject:* Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!
> >
> >
> >
> > Robert,
> > Good advice.
> > I am no expert but I believe you can't rely too heavily on any tube
> > tester. The actual circuit where the tube goes is the best tester.
> >
> > I downloaded the 51s1 manual just to have a look. The BFO is one tube. I
> > would try another, there are probably many types that could substitute
> > there if you don't have a good spare. I am thinking it maybe has a
> > filament to cathode short or leakage of some kind that lets the AC filament
> > signal onto
> > the BFO signal. But just a guess.
> > 73,
> > Gary
> > WB6OGD
> >
> >
> > --
> > 73 don va3drl
> >
> >
> >
>
>
>
>
>

--

73

-Jim
NU0C

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You receive all messages sent to this group.

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Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

A general purpose tube tester is great for sorting out gross defects. But the devil is in the details, such as high frequency RF circuits and high impedance AVC/AGC.

An old school TV repairman taught me years ago that you don't toss a tube just because it tests low/weak/bad on a tester. If it works to spec in circuit it is "good".

73

-Jim
NU0C

On Fri, 19 Jan 2024 19:42:34 -0800
"Robert Lonn WA6PHN" <roblonn@cox.net> wrote:

> Don, as I mentioned in my other post, see below, I now have 4 tube testers and they are precision high end devices, hopefully they can expose any tube issues that might come up.. Robert WA6PHN

--

73

-Jim
NU0C

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Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

Nevertheless, it remains a fact that a tube can be "good" on a tube tester and fail in circuit, and vise-versa. That is why it is said that the best test of a tube is the circuit that you want it to work in.

73

-Jim
NU0C

On Fri, 19 Jan 2024 22:19:09 -0500
"Lou WA5LOU" <loueverettsr@gmail.com> wrote:

> I've relied on mine for years and years and it has never failed me! I
> could not work on Tube rigs speedily without it!
>
> Lou WA5LOU
>
> On Fri, Jan 19, 2024 at 10:12 PM Don Root VA3DRL <
> drootofallevil@teksavvy.com> wrote:
>
> > Robert and all
> >
> > Re "I am no expert but I believe you can't rely too heavily on any tube
> > tester. "
> >
> >
> >
> > Well if it "reads bad" it likely *is bad. *
> >
> > if it "reads good" it may well be * good *under the condition it is
> > being tested at*. *
> >
> > Most TTs measure Gm [where amplification is part of the intent in the
> > tube.]
> >
> > If you have a variable Mu tube you really want to know if it works
> > properly with a small bias. But you want it to also work properly at a
> > large negative bias
> >
> > .. if you don't test it down there you might not know it has too hi a gm
> > .. maybe that is where the gas messes things up like Jacques said.
> >
> > I recently saw other postings somewhere the front end tube tested ok …
> > but did similar things
> >
> > .. but we need to get the books out on the details
> >
> >
> >
> >
> >
> >
> >
> > *From:* Amateur-repairs@groups.io [mailto:Amateur-repairs@groups.io] *On
> > Behalf Of *Gary WB6OGD
> > *Sent:* Friday, January 19, 2024 11:58 AM
> > *To:* Amateur-repairs@groups.io
> > *Subject:* Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!
> >
> >
> >
> > Robert,
> > Good advice.
> > I am no expert but I believe you can't rely too heavily on any tube
> > tester. The actual circuit where the tube goes is the best tester.
> >
> > I downloaded the 51s1 manual just to have a look. The BFO is one tube. I
> > would try another, there are probably many types that could substitute
> > there if you don't have a good spare. I am thinking it maybe has a
> > filament to cathode short or leakage of some kind that lets the AC filament
> > signal onto
> > the BFO signal. But just a guess.
> > 73,
> > Gary
> > WB6OGD
> >
> >
> > --
> > 73 don va3drl
> >
> >
> >
>
>
>
>
>

--

73

-Jim
NU0C

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View/Reply Online (#91156): https://groups.io/g/Amateur-repairs/message/91156
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Unsubscribe: https://groups.io/g/Amateur-repairs/leave/4530700/693790/458576413/xyzzy [jhjoshan@gmail.com]
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Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

Don, as I mentioned in my other post, see below, I now have 4 tube testers and they are precision high end devices, hopefully they can expose any tube issues that might come up.. Robert WA6PHN

When I first did this I only had a B&K 747 tube checker, but last year I visited an estate sale and picked up 3 nice tube checkers…

A Heathkit TT-1, A Triplet 3444A and a Hickok 539C.. Good to be the first on site at 6:30am so I could get the pick of the litter.. Also grabbed all the Tubes, probably around 850 or so..

Robert and all

Re "I am no expert but I believe you can't rely too heavily on any tube tester. "

Well if it "reads bad" it likely is bad.

if it "reads good" it may well be good under the condition it is being tested at.

Most TTs measure Gm [where amplification is part of the intent in the tube.]

If you have a variable Mu tube you really want to know if it works properly with a small bias. But you want it to also work properly at a large negative bias

.. if you don't test it down there you might not know it has too hi a gm .. maybe that is where the gas messes things up like Jacques said.

I recently saw other postings somewhere the front end tube tested ok … but did similar things

.. but we need to get the books out on the details

--
73 don va3drl

Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

I've relied on mine for years and years and it has never failed me! I could not work on Tube rigs speedily without it!

Lou WA5LOU

On Fri, Jan 19, 2024 at 10:12 PM Don Root VA3DRL <drootofallevil@teksavvy.com> wrote:

Robert and all
Re   "I am no expert but I believe you can't rely too heavily on any tube tester. "

Well if it "reads bad" it likely is bad.
if it "reads good" it may well be   good under the condition it is being tested at.
Most TTs measure Gm [where amplification is part of the intent in the tube.]
If you have a variable Mu tube you really want to know if it works properly with a small bias. But you want it to also work properly at a large negative bias
.. if you don't test it down there   you might not know it has too hi a gm .. maybe that is where the gas messes things up like Jacques said.
I recently saw other postings somewhere the front end tube tested ok … but did similar things
.. but we need to get the books out on the details

From: Amateur-repairs@groups.io [mailto:Amateur-repairs@groups.io] On Behalf Of Gary WB6OGD
Sent: Friday, January 19, 2024 11:58 AM
To: Amateur-repairs@groups.io
Subject: Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

Robert,
Good advice.
I am no expert but I believe you can't rely too heavily on any tube tester. The actual circuit where the tube goes is the best tester.

I downloaded the 51s1 manual just to have a look. The BFO is one tube. I would try another, there are probably many types that could substitute
there if you don't have a good spare. I am thinking it maybe has a filament to cathode short or leakage of some kind that lets the AC filament signal onto
the BFO signal. But just a guess.
73,
Gary
WB6OGD

--
73 don va3drl

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Groups.io Links:

You receive all messages sent to this group.

_._,_._,_