need IC


DANNN31
 

Hello,

I am having a problem finding a replacement IC for a Tektronix 212 scope.
The Tek part
number is 156-0280-00 and the MFR part number is SN74L72N. Does anyone have
one or know where I can get this part?

Thanks,
Dan Tulloss


Robert Morein <morepub@...>
 

THe part number is standard low power TTL.
Possibly Digikey.

----- Original Message -----
From: Dan Tulloss
To: 'TekScopes@yahoogroups.com'
Sent: Thursday, November 06, 2003 10:17 AM
Subject: [TekScopes] need IC


Hello,

I am having a problem finding a replacement IC for a Tektronix 212 scope.
The Tek part
number is 156-0280-00 and the MFR part number is SN74L72N. Does anyone have
one or know where I can get this part?

Thanks,
Dan Tulloss


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Jeff W <vwthingy@...>
 

Standard low power TTL, yes. However, very obscure part; single J-K
flip flop. Out of production by the majors. So Digikey, Mouser, and
the like will not have it. Suggest you go to the surplus houses
looking for it.

You may have more luck with the straight SN7472N part. I doubt that
it will affect the operation of the circuit; you should check it out
to be sure.

I know the local surplus place here in San Diego, Gateway, carries
the SN7472N, but not the L version.

Jeff


Robert Morein wrote:
THe part number is standard low power TTL.
Possibly Digikey.
Hello,

I am having a problem finding a replacement IC for a Tektronix
212 scope.
The Tek part
number is 156-0280-00 and the MFR part number is SN74L72N. Does
anyone have
one or know where I can get this part?


Bruce Lane
 

Hi, gang,

*********** REPLY SEPARATOR ***********

On 06-Nov-03 at 18:09 Jeff W wrote:

Standard low power TTL, yes. However, very obscure part; single J-K
flip flop. Out of production by the majors. So Digikey, Mouser, and
the like will not have it. Suggest you go to the surplus houses
looking for it.

You may have more luck with the straight SN7472N part. I doubt that
it will affect the operation of the circuit; you should check it out
to be sure.
Suggestion: If the original chip is socketed, it would probably be pretty easy to construct an adapter to allow the use of a more modern replacement, such as a 74L or LS76.


-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Bruce Lane, Owner & Head Hardware Heavy,
Blue Feather Technologies -- http://www.bluefeathertech.com
ARS KC7GR (Formerly WD6EOS) since 12-77 -- kyrrin@bluefeathertech.com
"Quando Omni Flunkus Moritati" (Red Green, aka Steve Smith)


ROLYNN PRECHTL K7DFW
 

Dan,

Use this tool......
http://www.findchips.com/avail

No luck with SN74L72N.
Got a hit using SN7472N.

K7DFW

..._._


John Miles <jmiles@...>
 

Couple of vendors on www.findchips.com show it in stock. Their
minimum-order fees may be prohibitive, though.

-- jm

-----Original Message-----
From: Jeff W [mailto:vwthingy@cox.net]
Sent: Thursday, November 06, 2003 10:09 AM
To: TekScopes@yahoogroups.com
Subject: [TekScopes] Re: need IC


Standard low power TTL, yes. However, very obscure part; single J-K
flip flop. Out of production by the majors. So Digikey, Mouser, and
the like will not have it. Suggest you go to the surplus houses
looking for it.

You may have more luck with the straight SN7472N part. I doubt that
it will affect the operation of the circuit; you should check it out
to be sure.

I know the local surplus place here in San Diego, Gateway, carries
the SN7472N, but not the L version.

Jeff



Craig Sawyers <c.sawyers@...>
 

Standard low power TTL, yes. However, very obscure part; single J-K
flip flop. Out of production by the majors. So Digikey, Mouser, and
the like will not have it. Suggest you go to the surplus houses
looking for it.
Or do what I've done in the past to replace an obsolete TTL part - shoehorn
in a modern part. If it is a JK, use instead a dual JK such as an LS73.
Solder or plug in power and ground, then cross wire the other pins into the
original '72 connections. Might have to be careful with preset and clear
connections - but beyond that it should be possible to stitch something
together that works.

Last thing I resurrected this way was my HP5328A counter.

Craig


Miroslav Pokorni
 

Do a search on Google and you will get few sources, among them
http://www.hobid.com/inventory/7/12.html and
http://www.sphere.bc.ca/test/hpparts.html . Parts will probably not be
cheap; I would guess several bucks a piece. The last letter in part number
specifies package and it can vary with manufacturer; the N is TI's
designation for plastic DIP, while their ceramic DIP is designated J. You
can use either package material. However, watch out that you do not get
ceramic flat pack; the 74L72 was also made in that style. Also watch that
you do not get regular TTL, 7472 (no L). They draw double current, roughly,
and can possibly cause problem with a small scope like 212.

You can also use 54L72, what is military temperature range, basically same
part just tested for that temperature range and parameters adjusted to hold
over that range.

Regards

Miroslav Pokorni

----- Original Message -----
From: "Dan Tulloss" <dtulloss@ntecusa.com>
To: <TekScopes@yahoogroups.com>
Sent: Thursday, November 06, 2003 7:17 AM
Subject: [TekScopes] need IC


Hello,

I am having a problem finding a replacement IC for a Tektronix 212 scope.
The Tek part
number is 156-0280-00 and the MFR part number is SN74L72N. Does anyone
have
one or know where I can get this part?

Thanks,
Dan Tulloss


Michael Dunn <mdunn@...>
 

At 12:51 PM -0800 2003/11/6, Miroslav Pokorni wrote:
can use either package material. However, watch out that you do not get
ceramic flat pack; the 74L72 was also made in that style. Also watch that
you do not get regular TTL, 7472 (no L). They draw double current, roughly,
and can possibly cause problem with a small scope like 212.
I'm not sure about the '72, but if I remember correctly, a lot of L TTL had (oddly enough) different pinouts from the other varieties. I have a vague memory of wiring up some 40085s once (some company's name for a 74C85, which I assumed to have a standard 74_85 pinout), and having the circuit not work too well until I rewired them as 74L85s!

Of course, if you end up subbing and rewiring, a 74HC(T) series part might work well too...

Michael


Miroslav Pokorni
 

The 74C series was a derivative of RCA's CD4000 series (metal gate CMOS), I
believe it was matter of trademark that prevented use of 4000 designation.
Some people paid royalties to RCA but National came up with 74C and
functional equivalent designation of TTL. In the process, some DIPs did get
weird pinouts.

Regards

Miroslav Pokorni

----- Original Message -----
From: "Michael Dunn" <mdunn@cantares.on.ca>
To: <TekScopes@yahoogroups.com>
Sent: Thursday, November 06, 2003 1:51 PM
Subject: Re: [TekScopes] need IC


At 12:51 PM -0800 2003/11/6, Miroslav Pokorni wrote:
can use either package material. However, watch out that you do not get
ceramic flat pack; the 74L72 was also made in that style. Also watch that
you do not get regular TTL, 7472 (no L). They draw double current,
roughly,
and can possibly cause problem with a small scope like 212.
I'm not sure about the '72, but if I remember correctly, a lot of
L TTL had (oddly enough) different pinouts from the other varieties.
I have a vague memory of wiring up some 40085s once (some company's
name for a 74C85, which I assumed to have a standard 74_85 pinout),
and having the circuit not work too well until I rewired them as
74L85s!

Of course, if you end up subbing and rewiring, a 74HC(T) series
part might work well too...

Michael