Phillip Potter

Soooo, do what others suggest, nice dinner for you, Michael, and your wives!!!

Phil

On 1/19/2020 1:43 PM, Siggi wrote:
Hey Denis,

looks like many people have reported they don't see their PayPal
transaction IDs in your log. I'm going to guess that PayPal assigns
different transaction IDs for each end of the transaction, at least in the
case where there are fees to pay and/or a currency exchange to be made.

Siggi

Re: Risetime calculator (in tekwiki)

Tony Fleming

Where is the calculator?
I do not want the virus one - someone said that one downloadable calculator
was a virus or bad calculator....
Thank you very much.
Tony

On Sun, Jan 19, 2020 at 9:15 AM Roger Evans via Groups.Io <very_fuzzy_logic=
yahoo.com@groups.io> wrote:

Albert,

Thanks for pointing that out, the calculator is quite different to what I
had imagined. I thought the resistance would increase in the clockwise
direction and each pot would just be connected as a two terminal variable
resistor. That does rely on having a good approximation to a square law
for the taper of the pot. As you pointed out the resistance increases ccw
and I can't see immediately why the maths works for the combination of
fixed resistor in parallel with the three terminal connected pot. It might
be a rather clever piece of algebra or an approximation that is good enough
for the intended application.

Roger

Siggi

Hey Denis,

looks like many people have reported they don't see their PayPal
transaction IDs in your log. I'm going to guess that PayPal assigns
different transaction IDs for each end of the transaction, at least in the
case where there are fees to pay and/or a currency exchange to be made.

Siggi

On Sat, Jan 18, 2020 at 11:57 AM Dennis Tillman W7PF <@Dennis_Tillman_W7PF>
wrote:

Wrapping up the TekScopes pledge drive, Michael Dunn and I are STUNNED by
contributions have exceeded the \$340 paid to Groups.io by almost 1,000%.
You
sent us 203 contributions totaling \$3,341.77!

We agree this is a problem that I will have to fix since it was my bright
idea. I did not realize when I sent my request for help that people would
be
so generous. I wrote, "So I am asking for small contributions". What
happened was anything but "small".

Leo Bodnar, a friend, stunned me when he contributed the entire required
amount two days later. This was the first sign I should have chosen a
synonym such as "tiny" or "teeny" instead of small. It was too late at that
point. I could see there was a tsunami headed my way and I had no way to
stop it. I think the contributions have finally stopped. The last one (I
hope) arrived three days ago.

Michael and I have decided that this is far too much money for us to keep
on
behalf of TekScopes. The simplest solution is for us to tear up the checks
and return all the PayPal contributions above \$10.00 (actually all those
above \$10.05) over the next few days, with our sincerest thanks. This will
result in exactly half of the contributions being kept and half being
returned. PayPal allows me to do a total refund very quickly; we considered
partial refunds, but the process would take much longer. If, after you
receive your refund, you would still like to make a contribution to
TekScopes, please don't send more than \$10.00. If you do, we'll be forced
to
spend it on wine and DMMs.

Thank You,
Dennis Tillman W7PF
Michael Dunn VA1XY

As I promised, here is every contribution I received. The four checking
account contributions are listed in numerical order by their bank account
number. Following those, the 199 PayPal contributions are listed in
numerical order by their transaction number. I double and triple checked
the
PayPal notices that came to me or to my wife, Marian, to be sure I didn't
miss any. If I missed your PayPal contribution please let me know so I can
find out what happened to it. The most common contribution was \$10.00 and
the average contribution was \$15.94.

CHECKING ACCOUNT
0000*255 \$50.00 TO BE REFUNDED
0035*054 \$20.00 TO BE REFUNDED
4650*2065 \$50.00 TO BE REFUNDED
9179*1067 \$50.00 TO BE REFUNDED

PAYPAL TRANSACTION
02079*******9581B \$10.00
03E74*******9033E \$100.00 TO BE REFUNDED
05P54*******33704 \$20.00 TO BE REFUNDED
0DV52*******9640N \$20.00 TO BE REFUNDED
0FX24*******0225D \$12.61 TO BE REFUNDED
0GH61*******5321H \$10.00
0H164*******7324J \$5.00
0HP31*******79205 \$10.00
0TB16*******6233S \$10.00
0V228*******9483Y \$15.00 TO BE REFUNDED
0WE54*******4492F \$20.00 TO BE REFUNDED
0XD49*******99831 \$10.00
0XX33*******5571C \$20.00 TO BE REFUNDED
10F89*******59157 \$20.00 TO BE REFUNDED
11D81*******1581M \$25.00 TO BE REFUNDED
13W62*******8082B \$5.00
16621*******82104 \$20.00 TO BE REFUNDED
16T81*******89037 \$21.00 TO BE REFUNDED
16U30*******4884J \$10.00
17T42*******7831E \$10.00
1C179*******04615 \$10.00
1C830*******8112P \$10.00
1KB10*******35308 \$10.00
1KC35*******1823E \$10.00
1KK41*******81702 \$40.00 TO BE REFUNDED
1MJ87*******7921S \$20.00 TO BE REFUNDED
1PL71*******8194S \$20.00 TO BE REFUNDED
1SF61*******75325 \$6.28
1U469*******7321A \$10.00
1UN19*******71331 \$21.50 TO BE REFUNDED
1XL88*******0010V \$10.00
21K47*******0942J \$5.00
26M35*******2652B \$20.00 TO BE REFUNDED
26W48*******18439 \$10.00
27955*******6435G \$2.00
28784*******31459 \$10.00
2AJ63*******9742M \$20.00 TO BE REFUNDED
2BB60*******7284T \$10.05
2C041*******7435F \$15.00 TO BE REFUNDED
2CF51*******55300 \$10.00
2GN07*******6691P \$21.36 TO BE REFUNDED
2HA37*******2763N \$20.00 TO BE REFUNDED
2JP56*******9614M \$6.00
2L669*******5001S \$20.03 TO BE REFUNDED
2LL81*******2181A \$10.00
2NX73*******6334E \$25.00 TO BE REFUNDED
2PE83*******8434J \$20.00 TO BE REFUNDED
2R866*******6484Y \$25.00 TO BE REFUNDED
2S663*******60054 \$10.00
2UD84*******92512 \$20.00 TO BE REFUNDED
2WG55*******8174X \$10.00
30988*******3613G \$10.00
31532*******3440H \$25.00 TO BE REFUNDED
32S52*******3263Y \$25.00 TO BE REFUNDED
33N46*******8874F \$20.00 TO BE REFUNDED
35J04*******2071X \$5.00
37611*******3481X \$30.28 TO BE REFUNDED
38D56*******6900H \$40.00 TO BE REFUNDED
38H00*******74637 \$10.00
39503*******91844 \$10.00
3C222*******60057 \$5.00
3DL81*******49307 \$10.00
3DN03*******6580W \$10.00
3HN95*******74316 \$20.00 TO BE REFUNDED
3JY75*******0415H \$10.00
3MK47*******8000V \$20.00 TO BE REFUNDED
3ML12*******7670M \$30.00 TO BE REFUNDED
3RW61*******7583B \$110.00 TO BE REFUNDED
3SV52*******0093K \$10.00
3U066*******6064R \$10.00
3W759*******4273V \$10.00
3WN84*******32644 \$20.00 TO BE REFUNDED
3X630*******09454 \$10.00
43V15*******1315P \$30.00 TO BE REFUNDED
43W14*******2963X \$10.00
4C132*******25402 \$20.78 TO BE REFUNDED
4CP43*******1271K \$15.00 TO BE REFUNDED
4E489*******92025 \$20.00 TO BE REFUNDED
4GU02*******14949 \$10.00
4H892*******5443S \$10.00
4NK97*******39943 \$30.00 TO BE REFUNDED
4NS27*******8414L \$20.00 TO BE REFUNDED
4PM01*******5380X \$10.00
4RA41*******16029 \$20.00 TO BE REFUNDED
4V179*******50029 \$25.00 TO BE REFUNDED
4VU25*******5244C \$10.00
4WE10*******2420U \$12.00 TO BE REFUNDED
4WG41*******2952L \$20.00 TO BE REFUNDED
4XH55*******98246 \$10.00
4XM94*******9951L \$20.00 TO BE REFUNDED
4XU29*******2203A \$5.00
52Y94*******9314H \$10.00
53E69*******9450U \$15.00 TO BE REFUNDED
53M48*******1162D \$10.04
54264*******83607 \$20.00 TO BE REFUNDED
54350*******3123J \$10.00
56419*******9740B \$10.68 TO BE REFUNDED
57958*******19248 \$10.00
57M28*******3463Y \$15.00 TO BE REFUNDED
58J72*******8751M \$5.05
59K74*******6614F \$10.00
59M25*******3721R \$10.72 TO BE REFUNDED
5FC22*******9632C \$10.00
5GA43*******4223M \$5.00
5K650*******2512S \$10.00
5L001*******9890K \$30.00 TO BE REFUNDED
5L631*******0780F \$5.00
5P795*******19647 \$20.00 TO BE REFUNDED
5SE25*******18324 \$20.00 TO BE REFUNDED
5UP40*******89642 \$20.00 TO BE REFUNDED
5UU92*******40032 \$10.20
61H86*******4671Y \$15.00 TO BE REFUNDED
61W04*******0651P \$5.00
62172*******4981K \$10.03
62762*******2074B REFUNDED
64M95*******0450J \$20.20 TO BE REFUNDED
69567*******7993L \$10.00
69G97*******6681W \$5.00
6AX91*******2221W \$10.00
6DC49*******7192J \$2.20
6DY20*******43532 \$10.00
6FR77*******2981V \$20.00 TO BE REFUNDED
6GH42*******5101K \$25.00 TO BE REFUNDED
6JF13*******51538 \$13.42 TO BE REFUNDED
6M239*******2634X \$20.00 TO BE REFUNDED
6M818*******3010R \$10.75 TO BE REFUNDED
6MW55*******8294T \$4.00
6NN32*******4542V \$10.00
6PN72*******3184X \$20.00 TO BE REFUNDED
6SJ24*******7280W \$10.00
6TX54*******6691J \$10.00
6UC87*******60625 \$5.00
6W050*******3122G \$25.00 TO BE REFUNDED
6YC11*******1694V \$10.00
6YR09*******24211 \$10.00
70R50*******48816 \$40.00 TO BE REFUNDED
71A57*******04246 \$20.00 TO BE REFUNDED
71B15*******9210H \$5.00
77749*******2345C \$5.00
7AA50*******6582S \$5.00
7BH77*******10502 \$10.00
7C686*******0453C \$20.00 TO BE REFUNDED
7C834*******0923E \$10.00
7CK01*******1245K \$5.00
7D080*******7730E \$10.00
7HC88*******8542G \$50.00 TO BE REFUNDED
7JC48*******6100G \$50.00 TO BE REFUNDED
7LV25*******2193G \$30.00 TO BE REFUNDED
7M285*******92740 \$25.00 TO BE REFUNDED
7MK85*******1842C \$10.00
7MS44*******5362B \$15.00 TO BE REFUNDED
7NK34*******5412S \$31.44 TO BE REFUNDED
7PE90*******5070C \$15.00 TO BE REFUNDED
7PW51*******11256 \$5.00
7SB72*******7192F \$20.00 TO BE REFUNDED
7UJ45*******9004U \$5.00
7V986*******7741K \$10.00
7WL39*******4140E \$10.00
80874*******3273N \$20.00 TO BE REFUNDED
82A24*******71901 \$20.00 TO BE REFUNDED
85T72*******59347 \$10.00
86464*******0522V \$25.00 TO BE REFUNDED
89L93*******2080C \$20.00 TO BE REFUNDED
8AB06*******94251 \$20.00 TO BE REFUNDED
8BM27*******0873M \$20.00 TO BE REFUNDED
8BP86*******45402 \$20.00 TO BE REFUNDED
8DF32*******6052V \$10.00
8EJ68*******08541 \$12.00 TO BE REFUNDED
8FJ75*******8872W \$20.00 TO BE REFUNDED
8GC22*******34141 \$25.00 TO BE REFUNDED
8GT73*******09326 \$12.61 TO BE REFUNDED
8MC99*******59946 \$11.00 TO BE REFUNDED
8N867*******6281R \$20.00 TO BE REFUNDED
8P783*******6711A \$23.00 TO BE REFUNDED
8PJ76*******6821F \$10.00
8TL81*******09540 \$20.00 TO BE REFUNDED
8X573*******06030 \$10.00
8XN50*******4422L \$20.00 TO BE REFUNDED
90T91*******35713 \$10.00
91410*******3142B \$10.00
91U38*******2105T \$11.00 TO BE REFUNDED
92261*******0350X \$10.00
94C22*******3914J \$50.00 TO BE REFUNDED
97618*******3223U \$20.00 TO BE REFUNDED
98Y68*******70508 \$1.24
99954*******8720E \$5.00
9A088*******0853S \$20.00 TO BE REFUNDED
9AP46*******63352 \$10.00
9B390*******8403F \$10.00
9DH47*******6461J \$10.00
9GJ81*******0164P \$10.00
9HK96*******73147 \$25.00 TO BE REFUNDED
9HS74*******5364F \$20.00 TO BE REFUNDED
9HY36*******94500 \$10.00
9KN17*******5330K \$5.00
9N383*******7605L \$5.36
9SK43*******0851N \$22.57 TO BE REFUNDED
9SN87*******3420T \$10.00
9UB93*******8990M \$20.00 TO BE REFUNDED
9V074*******7422K \$5.37

--
Dennis Tillman W7PF
TekScopes Moderator

Paul Amaranth

I concur. Consider it an appreciation award from the members of Tekscopes :-)

Paul

On Sun, Jan 19, 2020 at 01:17:54PM -0800, Errick wrote:
A nice dinner for two \$250
A couple of bottles of wine \$100
Taking care of TekScopes, Priceless!
Dennis and Michael should: Put some of the money in your wallets.
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@... | Unix & Windows

Errick

A nice dinner for two \$250
A couple of bottles of wine \$100
Taking care of TekScopes, Priceless!
Dennis and Michael should: Put some of the money in your wallets.

Richard in Edenton NC

Dennis, I did not see mine in the list.

January 1st for \$20.00

3SH79206CC5260117 via PayPal

I don't need it back. Please put it in a savings account aside for the future of the group. Or donate to a local ham club. Glad the group is here and I learn lots and enjoy it much.

73 Richard W4MCD

Re: 465 (Late S/N) Timing Board (A7) 670-3467-00?

DaveH52

DaveH52

Maybe ask for just one dollar next time.

Re: Risetime calculator (in tekwiki)

Albert Otten

On Sun, Jan 19, 2020 at 09:07 PM, Leo Bodnar wrote:

It's not intuitive but if you do the math it is, indeed works out perfectly
linear - assuming the trim pots are set to the value of 50R.
Whoever designed it, deserves to be an employee of the month.
These days such a gadget would have at least some duino inside it.
Leo
On Sun, Jan 19, 2020 at 05:28 PM, Albert Otten wrote:
Actually the math appears to be surprisingly simple and in theory the
instrument shows EXACT results with LINEAR pots..
This originates I think from the idea that around a maximum or minimum a function is quadratic plus higher order terms.
If you short together both ends of a linear pot then the resistance to the wiper is maximum midway and decreases quadratically (in this case exact, without higher order terms) when moving away from midway. In our instrument consider a wiper as a wiper of a 10 k pot, blocked midway in one direction.
I must confess that I only recognized the trick after further investigation.

Albert

Phillip Potter

Hi Dennis,

As a list owner, I can attest to the amount of work that it can be.

PLEASE keep my donation for the future, and even (as someone else said) take your wife and Michael and his wife out to a nice dinner on us.

Best wishes for 2020,

Phil

Re: Risetime calculator (in tekwiki)

Leo Bodnar

It's not intuitive but if you do the math it is, indeed works out perfectly linear - assuming the trim pots are set to the value of 50R.
Whoever designed it, deserves to be an employee of the month.
These days such a gadget would have at least some duino inside it.
Leo

On Sun, Jan 19, 2020 at 05:28 PM, Albert Otten wrote:
Actually the math appears to be surprisingly simple and in theory the instrument shows EXACT results with LINEAR pots..

Re: Risetime calculator (in tekwiki)

Chuck Harris

Albert has already determined that the taper of the pots is
*linear* and the scales of the two pots are *linear*, and
proved it out mathematically.

Read his description of the math.

And, the schematic is just fine. The negative terminal is
implied.

-Chuck Harris

Roy Thistle wrote:

Hi Dave:
If you have a chance... maybe you can determine the taper of the pots, with an multimer/ohmmeter (they are all identical, stamped 5000, 140416).
You might have to disconnect the wiper lug, and one of the others, on a pot, to avoid a lot of parallel resistance, from the other parts of the circuit.
It would be nice to know, if indeed, they are log taper pots. (The could be quadratic taper... I guess... but, that would be rare?)
Best regards, best wishes.
Roy

EB4APL

Hi,

I'm sure that I'm something wrong, but I don't see the list of contributors. A cue is appreciated.

Ignacio, EB4APL

El 18/01/2020 a las 20:59, Steve Hendrix escribiÃ³:
At 2020-01-18 01:07 PM, Colin Herbert via Groups.Io wrote:

I don't see my contribution, which had the transaction number
Likewise for mine, transaction #97334760EC9519925, Dec 31. Glad to donate, I know how much work it is to keep something like this running, and I greatly enjoy all the stories from the "old greybeards" who designed the equipment that I could only drool over during college and afterwards, back in the 70's and 80's. My donation said it went to Marian Tillman, whom you've already explained is your other half. Let us know if we should go complain to PayPal and get the money back to send to you another way.

Steve Hendrix

Re: Risetime calculator (in tekwiki)

Albert Otten

Hi GerryR, see for instance https://groups.io/g/TekScopes/message/163507 .
Albert

Re: Risetime calculator (in tekwiki)

Albert Otten

On Sun, Jan 19, 2020 at 07:54 PM, Roy Thistle wrote:

Hi Albert:
Though it has been mentioned... I think because the pot scales are marked off,
linearly... one needs to use log tapered pots (math won't change, unless you
add in the function(s) necessary to express resistance as a function of shaft
rotation.)
Best wishes and regards
Roy
I'm not sure I understand what you mean Roy. The x in my story is linear in the rotation angle, linear but rescaled to run from 0 (fully ccw) to 1 (fully cw). Of course you can avoid the angle in the expressions when you call the pot parts say R1 (top) and R2 (bottom), with R2 = R - R1. Then in the expressions x has to be replaced by R1/R. You end up with quadratic expressions in R1/R. So the scale has to be linear function of R1/R, otherwise you would not get a quadratic function in the scale reading. The easiest way to draw the markings is linear in angle, which only applies when the pots are linear.

Albert

Re: Risetime calculator (in tekwiki)

GerryR

Albert,
That's great, but where do you use such an instrument. I'm trying to figure out where three risetimes, or two as the case may be, react to give me a single total risetime. It's a neat calculator, but where do you use it?
GerryR

----- Original Message -----
From: "Albert Otten" <aodiversen@...>
To: <TekScopes@groups.io>
Sent: Sunday, January 19, 2020 12:28 PM
Subject: Re: [TekScopes] Risetime calculator (in tekwiki)

Actually the math appears to be surprisingly simple and in theory the instrument shows EXACT results with LINEAR pots..
Suppose all fixed (plus their trimpots) and variables have equal resistance R (5 k in our case).
Each pot is in parallel with one fixed resistor.
The wiper of a pot splits the pot resistance in xR (top part) and (1 - x)R (bottom part) where x varies linearly with angle from 0 (ccw) to 1 (cw).
The effective resistance, say z, of one pot circuit is seen between wiper and bottom terminal. The path consists of parallel (1 -x)R and xR + R = (1 + x)R.
Hence z = (1 - x)R*(1 + x)R / [(1 - x)R + (1 + x)R] = (1 - x^2)R^2 / (2R) = R(1 - x^2)/2.
There is the quadratic function we need!
To make it complete:
F branch including the extra R to the meter: R + zF = R + R(1 - xF^2)/2 = (3/2)R - (R/2)*xF^2,
A+B+C branch: zA + zB + zC = R(1 - xA^2)/2 + R(1 - xB^2)/2 + R(1 - xC^2)/2 = (3/2)R - (R/2)*(xA^2 + xB^2 +xC^2)
Balance when xF^2 = xA^2 + xB^2 +xC^2.
Q.E.D.

Albert

On Sun, Jan 19, 2020 at 04:15 PM, Roger Evans wrote:

Albert,

Thanks for pointing that out, the calculator is quite different to what I had
imagined. I thought the resistance would increase in the clockwise direction
and each pot would just be connected as a two terminal variable resistor.
That does rely on having a good approximation to a square law for the taper of
the pot. As you pointed out the resistance increases ccw and I can't see
immediately why the maths works for the combination of fixed resistor in
parallel with the three terminal connected pot. It might be a rather clever
piece of algebra or an approximation that is good enough for the intended
application.

Roger

Re: Risetime calculator (in tekwiki)

Roger Evans

Thanks Albert, I did one spot calculation with ABC at mid-travel and the result was exact so I was just settling down to do the full calculation.

Roger

Re: 7A26 transient response 5 nS all atten

Albert Otten

Hello Jon,

Difficult to read in the picture, but for probe calibration remember that the input capacitance changed at some S/N from 20 pF to 22 pF.
I also have several 7A26s as general purpose plugins. Saves time and wear when going from one scoop to another.

Albert

Hi Dennis,
I haven't been able to make my contribution without paying a transfer fee going to Paypal. I tried but couldn't because of my funds coming from outside the USA (where you as the beneficiary live), although ISTR having been able to make transfers to USA beneficiaries (as a friend or family) before, without paying a fee.
I think I'll lose the Paypal fee on refunding.

BTW, I can't find my transaction dated January 1, #2AA90158M6841150H @ USD 22,57.

So, please if you can, find my transfer and do something good with the money.
That would exclude refunding.
As far as I'm concerned, it would include having a bite with your wife, who probably suffers enough from all the time you spend moderating TekScopes

Raymond

Re: 555 replacement pair fan motor

John Williams

Hi David. I noticed a fan motor listed on eBay. I have had much success repairing these motors. I take them apart so I can clean and re lubricate the bushings. This usually works although not always. I have gotten rid of most of those although I think I have one or two still around. If you get really stuck let me know and I will take a look. John