I need a electronics supplier recommendation; see details

[Gunstar]

I'm looking to purchase a 74s139 and 74HC158. I already ordered a bunch of stuff from Digi-key, but these components they did not have for sale individually, only in 300+ quantities. I need somewhere I can buy them 1 at a time. Thanks!

[HiassofT]

I'm looking to purchase a 74s139 and 74HC158. I already ordered a bunch of stuff from Digi-key, but these components they did not have for sale individually, only in 300+ quantities. I need somewhere I can buy them 1 at a time. Thanks!

You could try Mouser or Newark, they have these chips on stock (in DIP).

 

so long,

 

Hias

[Gunstar]

Thanks, I checked into those, and Mouser has one but not the other, and Newark wants to charge me $20 for handling $2 in merchandise. So I need some more alternatives.

[unholy]

74HC158 & 74S139, both in stock at Mouser...

[kenfused]

Thanks, I checked into those, and Mouser has one but not the other, and Newark wants to charge me $20 for handling $2 in merchandise. So I need some more alternatives.

i used to get most of my ics and related parts from bgmicro but their selection has been dwindling over the years. they have the ls139s but not the hc158s. sometimes i have been lucky on ebay too.

[+bob1200xl]

Jameco??

 

Sometimes you need to be flexible when you specify ICs. The 139, for example, could probably work with the faster CMOS parts, which were not available when the part was originally spec'd. Nobody uses 'S' parts anymore - that's why you can't find them.

 

Bob

 

 

I'm looking to purchase a 74s139 and 74HC158. I already ordered a bunch of stuff from Digi-key, but these components they did not have for sale individually, only in 300+ quantities. I need somewhere I can buy them 1 at a time. Thanks!

[kenfused]

i used to get most of my ics and related parts from bgmicro but their selection has been dwindling over the years. they have the ls139s but not the hc158s. sometimes i have been lucky on ebay too.

Doh didn't notice it was S139 and read LS139. You might be able to substitute another type like F, ALS, or HCT depending on speed that is needed.

[+David_P]

If you don't mind ordering from Thailand, http://www.futurlec.com has a wide array of parts, generally at good prices, with no minimums.

[sloopy]

If you don't mind ordering from Thailand, http://www.futurlec.com has a wide array of parts, generally at good prices, with no minimums.

 

i order from futurlec also...

 

sloopy.

[Gunstar]

Thanks guys, I'll check this stuff out. As for nobody using "s" parts anymore, I guess your wrong. I do. Anyone who works with 25+ year old computers will at some point. Yeah, I know there may be newer alternatives, and I'd use them if I were doing my own circuits, but since I'm doing upgrade mods by others, I definately want to use exactly the same parts as them to make sure it is right, besides, I'm too lazy to research alternatives. If an elctronics supplier lists an alternative next to the original, then I'll take it.

Edited November 26, 2011 by Gunstar

[Gunstar]

74HC158 & 74S139, both in stock at Mouser...

 

Thanks, don't know how I missed one before...ordered and done. Thanks for the help.

[HiassofT]

Another question: What do you need the 74HC158 for?

 

Speaking generally, it's the wrong type for use in an Atari computer. You need to use chips with TTL compatible inputs, like 74HCT, 74LS etc. 74HC chips have CMOS inputs, with a different high/low threshold voltage and they can cause all sorts of (intermittent) problems when driven by a TTL output.

 

so long,

 

Hias

[Gunstar]

It's for a 1 megabyte 30-pin simm memory upgrade.

[HiassofT]

It's for a 1 megabyte 30-pin simm memory upgrade.

Which one would that be? Never heard of a RAM upgrade using 74HC158 chips (which would be the wrong type, anyway).

 

so long,

 

Hias

[Gunstar]

It's for a 1 megabyte 30-pin simm memory upgrade.

Which one would that be? Never heard of a RAM upgrade using 74HC158 chips (which would be the wrong type, anyway).

 

so long,

 

Hias

 

It's Bob Wooley's upgrade...I think he knows what he's doing: http://atari.a8maest...ry/simm1meg.htm

Unless it's a mistake in his schematic drawing. But it's all HC chips...4 total.

Edited November 26, 2011 by Gunstar

[HiassofT]

It's Bob Wooley's upgrade...I think he knows what he's doing: http://atari.a8maest...ry/simm1meg.htm

Unless it's a mistake in his schematic drawing. But it's all HC chips...4 total.

Phew.

 

Yes, usually Bob knows what he's doing, but this specific upgrade has 2 issues:

- input thresholds of HC chips (LS or HCT would be fine) might lead to intermittent problems

- combining REF and CAS with an AND gate (to generate kind of CAS-before-RAS or hidden refresh) is problematic with a lot of SIMMs (I think I wrote a few postings about this issue here).

 

so long,

 

Hias

[Gunstar]

Well, thanks for the heads up, if I have a problem I'll look into the alternatives, but I have a box full of 30-pin simm cards, so if I have a problem with the simm, I've got plenty of different brands to try.

[kurtm]

I'm looking to purchase a 74s139 and 74HC158. I already ordered a bunch of stuff from Digi-key, but these components they did not have for sale individually, only in 300+ quantities. I need somewhere I can buy them 1 at a time. Thanks!

 

I use bgmicro.com periodically. They are a surplus-like store. They didn't have 74s139, but did have 74hc139. It's been a while since I actually ordered, but I don't recall shipping being outrageous.