Help finding 74HCTLS132N IC

[xxxdavidmaysxxx]

Hey there. I was wondering if anyone knew somewhere that I could find an 74HCTLS132N IC. All the parts houses i've found are being greedy bastards and won't sell to you unless you spend 400 dollars. It has 16 pins, btw. If you know if an equivelent, or somewhere that I can get one, I will get your name tattooed on my calve.

[xxxdavidmaysxxx]

Actually looking at the original schematics, it says a 74S138 is in that slot...  Looks like something to try tell you how it goes when I get it.

[Futureman]

Is this one of the IC's that you broke it's pin off?

It doesn't seem like you are looking very hard ..    Ebay is often really cheap for IC's..
Pretty standard 74 series IC.

http://shop.ebay.com.au/?_from=R40&_trksid=p3907.m570.l1313&_nkw=74HCT132&_sacat=See-All-Categories

Why would you put in another IC into it's slot? Maybe the Schem's are wrong or have a typo, or you are looking at the wrong IC. If it was a 74HCT132 in there, and you didn't mess up the IC's and their relative positions, don't go putting in another IC.

They are completely different IC's... one is a Quad 2 input Nand Schmit & the other is a multiplexer.. light years apart.

Regards
Mike

[xxxdavidmaysxxx]

But you see, it was not a plain old 74hct132.... That particular IC only has 7 pins, believe it or not. I checked... I have the chip right here and it is a 74HCTLS132N, ZX branded, date code 8514, and eight pins. It went into IC slot 80, Trust me, I wish you were right :p. I got the info from the schems at the yahoo users group, and I checked some other ICs and they're positions against my EII and they were the same, except this one in question, of course. And I already ordered this peice off of ebay (I aint payin no $75 minumum!) I have looked very hard on google for this part, and by that I mean solid concrete data and came up with none. It looks like I have no choice but to try it... Heres a pic of the IC (for whatever reason   )



After I broke this IC, I put a small sharpie mark on the board away from any current path so that I could remember where to look if it did not work again. But I guess I'll check around some more to check the schematics validity and make sure I didn't commit any all to common human error

[Futureman]

Personally, when something like this has happened in the past to me...

1- I've cut a resistor leg off.. bashed it semi-flat with a few knocks of a hammer, then soldered it onto the broken leg, and then cut to length.

2- Or, you could solder it into an IC holder, and then insert the lot into your E2. (get a IC holder with machined pins etc.. better fit into E2's IC holder.

If you are decent with a soldering iron, this should only take a few seconds for (1).. or take your time with (2) to let the IC stay cool.. ie, 1 pin, wait 20 secs.. 2nd pin.. wait..

Best of luck.
Mike

[xxxdavidmaysxxx]

Thanks Mike, you've been helpful. I actually did that exact thing, I cut off a leg from a small little switch that was useless to me and soldered it on. But alas it did not work. But I looked closer at the schematics, and every slot where it says to have an 74S138, consistantly turns up to have the "mystery chip" inside it.

So at one point E-MU decided to switch to this possibly custom IC from the 74s138. Right now, I'm ordering both a MT-something-15 memory chip, and the replacement 74s138 for the sake of completeness and so if it still does not work after I install the new EPROMS, I can rule those out. if the eproms don't fix it, I'm going to borrow my Uncles multi-meter and check all the chips to find faults. I've never taken any of my musical instruments to a tech in my life, and I'm not going to without a fight!  . This is actually (as I'm sure you've noticed) my first venture into "complicated" electronics. I've rewired guitars and fixed tube amps before. But nothing quite like this....

[Elmbeatz]

you'll get it up running!!! 

[Futureman]

Seriously.. as I mentioned before.. eeproms are pretty much indestructable... 

Personally, I'd rule the eeproms out as a source of the fault.

What about the connectors between the two boards, or any other physical contact between the board and something else.

Also, a Multimeter will NOT tell you whats wrong with an IC..

It will tell you if various parts on the board are getting the correct voltage... but generally, if one IC is getting the correct 5V that is needed to make it run on a PCB, all other IC's on that board that need 5V will be also..
(There is also a potential that you will damage some logic IC's blindly putting a multimeter on pins looking at voltages)

I'd still be looking for something you potentially messed up while reseating the IC's and not some other fault... I'd be looking REAL hard for more bent pins. REAL hard.

I haven't looked into what a 74HCTLS132N is but if you get an answer, post it up here.

Good luck

[xxxdavidmaysxxx]

Thanks for the encouragement Elmbeatz! I sure as hell need it .

And I think I'll just sit down, either tonight or tomorrow. And go through every square inch. I'll check under the boards, I'll check all the ICs, I think the ribbon conections are solid enough, though . One thing that concerned me about the main eprom (The one that may very well be causing these issues) Is that the label on it is creased in the middle, and maybe even a little raised up. I don't know exactly how much light is needed to erase one... Do you know if that could be a possibility? And is there no way to test ICs other than trial and error?

I have to get this working. I've seen people fix synths with broken boards by wiring the current paths back together, and salvaging ones with 20 years of coca cola corroding away at all of the components after a spill. I couldn't have just screwed everything up by cleaning it. I'll see if my father wants to take a peek, so that maybe another pair of eyes will see something I missed. It HAS to be fixable!

But thanks for the help Errrybody. If it werent for you all I would have been swapping random ICs with new ones that have nothing to do with anything at all.

[Futureman]

Ribbon cables are often a major source of faults in synths.

The cable is just pressed into a lot of 'V' type forks.. this is a ok connection.. but 30 years later after a bit of oxidisation, they can get pretty bad and intermittent..  Same with mixing consoles.. many of the buss connections on them are done with Ribbon cable and IDE type connectors.

My Prophet5 had problems with jitter on it's control surface, and that was the problem. - $0 for me to fix..

My Memorymoog had a weird problem with one osc drifting in pitch.. that was the problem. - $0 for me to fix.

The amount of gear that I've bought & fixed all because of poor contacts is huge.. I've picked up heaps of gear that was not 100% working (And just bought another E2 that is not 100%... and I'm putting money on it that it's poor contacts.. most likely IC sockets.)

I just recently picked up 2x Primetime 93 delays for F- all.. probems? Poor contacts with IC mounts and Op-amps.. and guess what, a bent pin where someone had tried to fix it.. lol. $0 for me to fix.

[Futureman]

Oh, the Ribbon cables on the E2 from memory only go to the display/switch board ja? So I doubt it's the fault..

That connector between the two boards however... see if you can unscrew one board and slide it out and back again, working that connector a few mm.

Also, regarding eeproms.. yea, a bit of light may have got in.. but it does take a fair bit of UV to erase an eeprom or corrupt it. I guess anything is possible.

In the past, I've seen some people on ebay burning custom eeproms for people.. (Data etc)
If you have the binary file, and know what model eeprom it is, you could go down that road for the hell of it.

Yes, I've fixed broken tracks by soldering them, and I've replaced dissolved tracks from Coke and battery acid.. but 'IF' you have a broken track, it won't be so obvious.(no coke or battery acid inside E2) . it'll be a hairline track a few 100th of a mm wide.
From my experience fixing dry joints (Some times an arse to find)... when I find the dry joint, you would seriously never know it was their.. stare at it with a magnifiying glass & still invisible.


Cheers
Mike

[Elmbeatz]

I have little knowledge of electronics. When my EII didn't work, I just did what you did - un-/replug all connectors / ICs and such. Thank god it worked again afterwards. I'm sure that if you fix your broken IC-legs somehow and give everything inside another push with your thumb, it will be runniung again.

There are ghosts in the machine which will go back sleeping if you take enough care of the machine. Just be careful to not wake them up again, after you got it back to life...

(SORRY for weird talking, but been heavy drinking last night...)