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Michael Black
Guest

Thu Jul 07, 2016 7:16 pm   



On Wed, 6 Jul 2016, jjrjra16988816_at_gmail.com wrote:

Quote:
I am interested in just the TENMA 72-2040 meter. I either had mine
stolen or I managed to lose it after 7 years of use. Please contact
jjrjra16988816_at_gmail.com

Come on, the original post is from 2000. The guy either sold the stuff
long ago, or trashed it. He's certainly not reading this newsgroup after
all this time, especially when this newsgroup has never had much traffic.

And this isn't a buy and sell newsgroup. There are newsgroups for that
over there.

Michael


Guest

Fri Aug 19, 2016 9:05 pm   



This is Annan old thread but I was going to throw away the cards I have and wonder if anybody is interested in them, since now PE is available on the net probable will be ok to scan them and give them away.
I noticed that most circuits are taken from the components datasheet a and some also have mistakes or non existing components

Michael A. Terrell
Guest

Wed Aug 24, 2016 1:58 am   



eduardo.artigas_at_gmail.com wrote:
Quote:
This is Annan old thread but I was going to throw away the cards I have and wonder if anybody is interested in them, since now PE is available on the net probable will be ok to scan them and give them away.
I noticed that most circuits are taken from the components datasheet a and some also have mistakes or non existing components



Offer them to http://www.archive.org or
http://www.americanradiohistory.com/


Guest

Mon Apr 16, 2018 8:45 pm   



Managed to score one my self in decent condition. Looking at the back of the unot dont reveal mich but that nine pin connector is numberd internally. Pin 1-9 from back of unit starting on the left. 1 gnd 2 gnd 3 gnd 4 -10v 5 SW 6 +10v 7 -27v 8 FL 9 FL. From my little experience the FL is most likely for the VFD display and can range any where from 16 to 24 volts. And the -27 volts is possibly for the internal op amps. Getting a positive and a negative voltage for 10 volts shouldent be too hard. I will try some experiments my self and I can drop you some messages if youd like

Adrian Caspersz
Guest

Tue Apr 17, 2018 11:45 pm   



On 16/04/18 20:15, xeratais_at_gmail.com wrote:
Quote:
Managed to score one my self in decent condition. Looking at the back of the unot dont reveal mich but that nine pin connector is numberd internally. Pin 1-9 from back of unit starting on the left. 1 gnd 2 gnd 3 gnd 4 -10v 5 SW 6 +10v 7 -27v 8 FL 9 FL. From my little experience the FL is most likely for the VFD display and can range any where from 16 to 24 volts. And the -27 volts is possibly for the internal op amps. Getting a positive and a negative voltage for 10 volts shouldent be too hard. I will try some experiments my self and I can drop you some messages if youd like


20 years ago, he would have been interested....

--
Adrian C

New England Area Ham - E
Guest

Sat Sep 15, 2018 1:45 am   



The Sept Flea is this Sunday... Have you put out a rally call to w1af??

73 Steve F
w1gsl
________________________________
>From: Collins, William E. [collins_at_chemistry.harvard.edu]
Sent: Thursday, August 16, 2018 8:57 PM
To: 'hwc-list_at_lists.hcs.harvard.edu'
Cc: Steven L. Finberg
>Subject: MIT Flea

Hi All, the August MIT Flea will be held this Sunday, August 19th.

The Harvard Wireless Club co-sponsors the Flea Market and it provides a sou
rce of funding for our club. It is also sponsored by the MIT Radio Society,
the MIT UHF Repeater Association, and the MIT Electronics Research Society
.. It is a good opportunity to meet some of the people over at MIT. Just go
the main gate, and announce to the folks at the gate that you are from the
Harvard Wireless Club and are there to work. There is a sign in sheet where
you will put down your name, callsign (W1AF) and time in/out. Usually memb
ers put in a few hours, whatever you decide you can do. Also, try to intro
duce yourself to Steve Finberg from MIT/W1XM, who "runs the show". Before o
r after you "work", be sure to spend some time to browse around, there are
always some interesting things there (only technical/scientific items gener
ally allowed).
It is held at the MIT garage at Albany and Main Street. Lately, it is based
on the 2nd floor.
Anyone with a Harvard or MIT ID gets a dollar off admission. In addition, H
arvard and MIT students are admitted free of charge (with school ID).

People are needed as early as 5:30 AM, and as late as noon- 1 PM. Last mont
h we had a shortage of people at the end, at 2 PM. So, whatever time may be
convenient for you, the club would appreciate any time that you could put
in at the Flea.

It is usually held on the third Sunday of every month until October. This y
ear's other remaining date are: 8/19, 9/16, 10/21.
Questions? w1af.harvard.edu

Thanks! 73 -Bill Collins W1PL


**************************************
William E. Collins W1PL
Electronic Technician IV
Harvard University
Department of Chemistry and Chemical Biology
Nuclear Magnetic Resonance Laboratory
12 Oxford Street, Box 41
Cambridge, Massachusetts 02138
1-617-495-4042<tel:1-617-495-4042>
collins_at_chemistry.harvard.edu<mailto:collins_at_chemistry.harvard.edu>
**************************************


_______________________________________________
Flea mailing list
Flea_at_mit.edu
http://mailman.mit.edu/mailman/listinfo/flea

Geo
Guest

Tue Oct 16, 2018 4:45 pm   



On Tue, 16 Oct 2018 14:04:24 +0100, James Harris
<james.harris.1_at_gmail.com> wrote:

Quote:
Having not touched any of this kind of stuff for years I'm looking to
power a small TTL test circuit which I intend to built on a breadboard.
I wondered if I could run it off USB power. In other words, is it
feasible to power a TTL cct via a USB lead and USB socket?

I found a "USB Mini B Breakout Board"

http://www.hobbytronics.co.uk/cables-connectors/usb-connectors/usb-minib-breakout

but I'm not sure that the PCB bit of it is necessary and, besides, it's
only rated for 100mA (which may be enough but I can't be sure at this
stage). If not USB, I guess I should go for a wall wart and a 7805.

So the question is whether there's a good way to power a circuit via
USB, or whether you think I should go down the wall-wart or some other
route.

Any suggestions?


I use the USB connector on my projects now even if they have no
connection to a PC. It gives the choice of a PC/Laptop or one of the
many cheap USB wall wart chargers or a car charger. The USB connector
is almost a standard but for home use the breakout board is convenient
as the holes are on 0.1" pictch so you can fit a header to plug it in
to a protoboard etc.

James Harris
Guest

Wed Oct 17, 2018 2:45 pm   



On 16/10/2018 15:45, Geo wrote:
Quote:
On Tue, 16 Oct 2018 14:04:24 +0100, James Harris
james.harris.1_at_gmail.com> wrote:

Having not touched any of this kind of stuff for years I'm looking to
power a small TTL test circuit which I intend to built on a breadboard.
I wondered if I could run it off USB power. In other words, is it
feasible to power a TTL cct via a USB lead and USB socket?

I found a "USB Mini B Breakout Board"

http://www.hobbytronics.co.uk/cables-connectors/usb-connectors/usb-minib-breakout

but I'm not sure that the PCB bit of it is necessary and, besides, it's
only rated for 100mA (which may be enough but I can't be sure at this
stage). If not USB, I guess I should go for a wall wart and a 7805.

So the question is whether there's a good way to power a circuit via
USB, or whether you think I should go down the wall-wart or some other
route.

Any suggestions?

I use the USB connector on my projects now even if they have no
connection to a PC. It gives the choice of a PC/Laptop or one of the
many cheap USB wall wart chargers or a car charger. The USB connector
is almost a standard but for home use the breakout board is convenient
as the holes are on 0.1" pictch so you can fit a header to plug it in
to a protoboard etc.


That's good. If USB power is stable enough (and, if not, I guess I could
add smoothing) then it seems the most convenient option, what with
sources including mains, computer, car battery, portable power pack etc.

As for the connectors, which do you use. I've seen a USB-B receptacle
which might do

https://uk.farnell.com/amp-te-connectivity/1734517-1/usb-connector-2-0-type-b-rcpt/dp/2778492?st=usb%20pcb


There's currently a better shot of the pins of a similar socket at

https://www.ebay.co.uk/itm/K1X4-10-Pcs-USB-Female-Type-B-Port-4-Pin-Right-Angle-PCB-DIP-Jack-Socket-V7S1/302801941235

Is that the connector you use or do you get enough current through a
Mini-B or Micro-B or something else?


--
James Harris

James Harris
Guest

Wed Oct 17, 2018 3:45 pm   



On 17/10/2018 14:41, James Harris wrote:
> On 16/10/2018 15:45, Geo wrote:

....

Quote:
I use the USB connector on my projects now even if they have no
connection to a PC. It gives the choice of a PC/Laptop or one of the
many cheap USB wall wart chargers or a car charger. The USB connector
is almost a standard but for home use the breakout board is convenient
as the holes are on 0.1" pictch so you can fit a header to plug it in
to a protoboard etc.

That's good. If USB power is stable enough (and, if not, I guess I could
add smoothing) then it seems the most convenient option, what with
sources including mains, computer, car battery, portable power pack etc.

As for the connectors, which do you use. I've seen a USB-B receptacle
which might do

https://uk.farnell.com/amp-te-connectivity/1734517-1/usb-connector-2-0-type-b-rcpt/dp/2778492?st=usb%20pcb


Incidentally, there's currently a type-A socket at

https://www.ebay.co.uk/itm/3pcs-USB-surface-PCB-mount-socket-Female-Type-A-connector-right-angle-ref-674-/283186649635

and its pins look like they might be more conveniently laid out /if/
they have 0.1" spacing. Can you see any reason not to use a type-A
connector on a device? Devices are supposed to use type-B.


--
James Harris

Geo
Guest

Wed Oct 17, 2018 4:45 pm   



On Wed, 17 Oct 2018 14:45:33 +0100, James Harris
<james.harris.1_at_gmail.com> wrote:


Quote:
Incidentally, there's currently a type-A socket at

https://www.ebay.co.uk/itm/3pcs-USB-surface-PCB-mount-socket-Female-Type-A-connector-right-angle-ref-674-/283186649635

and its pins look like they might be more conveniently laid out /if/
they have 0.1" spacing. Can you see any reason not to use a type-A
connector on a device? Devices are supposed to use type-B.


Might be more difficult to find a suitable cable.
I have used a type B similar to the one you mentioned but horizontal
mounting. The 4 pins squeezed into a 0.1 pitch veroboard but the two
mouting holes had to be enlarged. Have also used the easier method
with the mini breakout and on one unit I just have a fixed cable with
type A at the end for power.

Geo
Guest

Sat Oct 20, 2018 5:45 pm   



On Sat, 20 Oct 2018 11:50:51 +0100, James Harris
<james.harris.1_at_gmail.com> wrote:


Quote:
Whether such a piece of kit would be generally useful or not, such an
analyser wouldn't help in this specific case as it could not be used to
check the above decoder without also using a test program to cycle
through the inputs. The decoder is not socketed so I guess all I can do
is unsolder the chip and test the 16 permutations of its inputs on a
breadboard. If I'm wrong and there is a better approach please say!


I have a piece of old kit (Fluke Trendar 200 IC Testclip) that we were
issued with when TTL was mainstream. It has a 16 pin clip to attach
to the suspect DUT and a 16 pin socket. A number of special socket
can be plugged in to the one on the unit. Each special can have long
or short pins - long pins connect to the input of the DUT short pins
only connect to the exclusive OR gates which drive the LEDs. A good
IC is placed in the socket and the leds indicate a difference between
the good and DUT outputs. There is also a pulse stretcher which can be
switched to any pin.

Some info on google and at least one on ebay:-
https://www.ebay.co.uk/itm/VINTAGE-FLUKE-TRENDAR-200-IC-TEST-CLIP-WITH-CASE-MANUAL-CABLE-PINS-REFERENCE-/232452265430

if that wraps then:-
https://tinyurl.com/y7oawq4k

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