Tech: Are SN7400 and SN7404N ICs Interchangeable?

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Archived from groups: rec.games.pinball (More info?)

See this dot . ,well everything I know about IC chips could be legibly
hand written in crayon on top of that dot.

I need to replace a SN7400 IC and I don't have one. I do have a
SN7404N. Are they interchangeable?

TIA


Rick Swanson
 
Archived from groups: rec.games.pinball (More info?)

> I need to replace a SN7400 IC and I don't have one. I do have a
> SN7404N. Are they interchangeable?

NO!

7400 is a quad (4 of them on 1 chip) 2 input NAND gate.

7404 is a 1 input inverting buffer.
 
Archived from groups: rec.games.pinball (More info?)

Rick Swanson wrote:
> See this dot . ,well everything I know about IC chips could be legibly
> hand written in crayon on top of that dot.
>
> I need to replace a SN7400 IC and I don't have one. I do have a
> SN7404N. Are they interchangeable?
>
> TIA
>
>
> Rick Swanson
hehe.. no.
like the crayon comment!
funny stuff!
 
Archived from groups: rec.games.pinball (More info?)

martin wrote:
> So, Rick... how do you know that you have to replace it?
>

Actually, I don't. I'm just guessing. Legs #7 and #9 both buzz out as
being grounded. On all the other SN7400N's only leg #7 buzzes out as
being grounded. I removed the resistor that was at the end of the trace
which immediately connects with leg #9 and leg #9 still buzzes out as
being grounded. Consequently, my guess is that the IC has some internal
problem.


Rick Swanson
 
Archived from groups: rec.games.pinball (More info?)

Rick Swanson <rns510@charter.net> wrote in news:sVXqe.8639$rt3.718
@fe03.lga:

> See this dot . ,well everything I know about IC chips could be legibly
> hand written in crayon on top of that dot.
>
> I need to replace a SN7400 IC and I don't have one. I do have a
> SN7404N. Are they interchangeable?
>
> TIA
>
>
> Rick Swanson
>

No. http://www.kingswood-consulting.co.uk/giicm/7400.html

--
inc
 
Archived from groups: rec.games.pinball (More info?)

johninc wrote:

> Rick Swanson <rns510@charter.net> wrote in news:sVXqe.8639$rt3.718
> @fe03.lga:
>
>
>>See this dot . ,well everything I know about IC chips could be legibly
>>hand written in crayon on top of that dot.
>>
>>I need to replace a SN7400 IC and I don't have one. I do have a
>>SN7404N. Are they interchangeable?
>>
>>TIA
>>
>>
>>Rick Swanson
>>
>
>
> No. http://www.kingswood-consulting.co.uk/giicm/7400.html
>


Thanks guys! I especially want to thank johninc for the link to the
"Giant Internet IC Masturbator".
http://www.kingswood-consulting.co.uk/giicm/

I've bookmarked it for future reference. 🙂


Rick Swanson
 
Archived from groups: rec.games.pinball (More info?)

Well, leg 7 is ground so that's OK. Leg 9 is an input, and it would be
quite reasonable for it to be grounded, although it sounds like it has
a pullup resistor. If you can tell us the game and U nuimber, I'll
check the schematic if I have it.
 
Archived from groups: rec.games.pinball (More info?)

Well, leg 7 is ground so that's OK. Leg 9 is an input, and it would be
quite reasonable for it to be grounded, although it sounds like it has
a pullup resistor. If you can tell us the game and U nuimber, I'll
check the schematic if I have it.
 
Archived from groups: rec.games.pinball (More info?)

Rick Swanson <rns510@charter.net> wrote in news:lFYqe.4372$Ub4.2894
@fe06.lga:

> Thanks guys! I especially want to thank johninc for the link to the
> "Giant Internet IC Masturbator".
> http://www.kingswood-consulting.co.uk/giicm/
>
> I've bookmarked it for future reference. 🙂
>
>
> Rick Swanson
>
>

You're welcome. It's an incredible resource, with a disturbing name.
Kinda fits in with pinball collectors. :)

--
inc
 
Archived from groups: rec.games.pinball (More info?)

I'm bookmarking it too. Really boils it down for quick reference!
Thanks John!

bogart
www.pinrestore.com

johninc wrote:
> Rick Swanson <rns510@charter.net> wrote in news:lFYqe.4372$Ub4.2894
> @fe06.lga:
>
>
>>Thanks guys! I especially want to thank johninc for the link to the
>>"Giant Internet IC Masturbator".
>>http://www.kingswood-consulting.co.uk/giicm/
>>
>>I've bookmarked it for future reference. 🙂
>>
>>
>>Rick Swanson
>>
>>
>
>
> You're welcome. It's an incredible resource, with a disturbing name.
> Kinda fits in with pinball collectors. :)
>
 
Archived from groups: rec.games.pinball (More info?)

Maybe somebody wrote BAD on it.

In crayon.

bogart
www.pinrestore.com

martin wrote:
> So, Rick... how do you know that you have to replace it?
>
 
Archived from groups: rec.games.pinball (More info?)

yes, ugly - looking at the schemtic, a sensitive TTL input exposed
directly to playfield voltages. Make a mistake under the pf and the
switch matrix is going down.

Rick, for what it is worth I would cut pin 9 and test again to prove
that it is the IC. That way, if it is a short or something you can
reconnect it.
 
Archived from groups: rec.games.pinball (More info?)

martin wrote:
> Well, leg 7 is ground so that's OK. Leg 9 is an input, and it would be
> quite reasonable for it to be grounded, although it sounds like it has
> a pullup resistor. If you can tell us the game and U nuimber, I'll
> check the schematic if I have it.
>

It's Z13 on the Control Board on Hollywood Heat.

Thanks,

Rick Swanson
 
Archived from groups: rec.games.pinball (More info?)

Ahh Rick,

it is ABOUT TIME you delve into the joys of Gottlieb System 80!!

Z13 is the TTL chip that buffers return lines R0, R1, R2, and R3, to the U4
6532 RIOT chip. This chip, as well as Z11, Z12, and Z14 (and Z15, depending
on who you ask) all comprise the "switch matrix" ICs the system 80 nerds are
perseverant over. Also, very commonly they are bad, and will prevent the
game from starting. Be sure to solder in a socket, before you replace that
chip. You may have to socket and replace the other mentioned chips as well,
before that board boots.

Good luck,
Dan (system 80 nerd-intern)

"Rick Swanson" <rns510@charter.net> wrote in message
news:xr3re.2149$eL5.1473@fe04.lga...
> martin wrote:
>> Well, leg 7 is ground so that's OK. Leg 9 is an input, and it would be
>> quite reasonable for it to be grounded, although it sounds like it has
>> a pullup resistor. If you can tell us the game and U nuimber, I'll
>> check the schematic if I have it.
>>
>
> It's Z13 on the Control Board on Hollywood Heat.
>
> Thanks,
>
> Rick Swanson
 
Archived from groups: rec.games.pinball (More info?)

"martin" <martin.reynolds@gmail.com> wrote in message
news:1118622915.646251.206190@g44g2000cwa.googlegroups.com...
> yes, ugly - looking at the schemtic, a sensitive TTL input exposed
> directly to playfield voltages. Make a mistake under the pf and the
> switch matrix is going down.

Yes Martin, you are correct about that, but better a cheap 7400 than an
almost obsolete, expensive 6532!

Regards,
Dan
 
Archived from groups: rec.games.pinball (More info?)

martin wrote:
> yes, ugly - looking at the schemtic, a sensitive TTL input exposed
> directly to playfield voltages. Make a mistake under the pf and the
> switch matrix is going down.


Yes, that is exactly what happened. The owner was replacing some burned
out bulbs with the game powered up. The next then he knew the game was
acting weird.

Thanks guys.

Rick Swanson
 
Archived from groups: rec.games.pinball (More info?)

Um, Rick? Does this mean you are working on someone else's machine? I
*know* your liability insurance is up to date, right?

Good of you to help out...

John!

Rick Swanson wrote:
>
> Yes, that is exactly what happened. The owner was replacing some burned
> out bulbs with the game powered up. The next then he knew the game was
> acting weird.
>
> Thanks guys.
>
> Rick Swanson
 
Archived from groups: rec.games.pinball (More info?)

GA Pinhead wrote:

> Um, Rick? Does this mean you are working on someone else's machine? I
> *know* your liability insurance is up to date, right?
>
LOL! No, but I told the guy my name was John Shields. ;-)


Rick Swanson
 
Archived from groups: rec.games.pinball (More info?)

In a Cajun accent no doubt. Oh wait that would be cannuck, or Italian...

John!

Rick Swanson wrote:
> GA Pinhead wrote:
>
>> Um, Rick? Does this mean you are working on someone else's machine?
>> I *know* your liability insurance is up to date, right?
>>
> LOL! No, but I told the guy my name was John Shields. ;-)
>
>
> Rick Swanson
 
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