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that.sound.again

Alternative to optocoupler 6N138?

9 posts in this topic

Hi there!

We're building two midiBox + on two boards from Mike. So far it's looking good, except the local parts shop doesn't carry the 6N138 optocoupler. We've gotten some other optocouplers with eight connectors, but how do we check if they work? We're not even sure how to read the type number correctly (kind of pathetic, I know).

The chip reads:

PC-17T

K804

01

(it says this twice on each chip). We've googled around a bit but are not really sure which number to search for to find a datasheet.

So, we'd be very grateful if someone could:

a) Tell us how to determine which type of chip this is and how to compare it to the 6N138 or

b) Just tell us whether this chip will do or if we'll have to find the 138.

Thanks in advance!

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The 6N138 optocoupler has been chosen after others, as it is the most suitable for these projects. (at least that's what I think) The CNY-172 (or was it the 3?) was used in early midibox designs, but did not interface well with some midi connections.

To get info on the part you have, try searching for a data sheet on the Farnell electronics website. (www.farnell.com if I remember correctly) (Try only the first line that appears on the Optocoupler)

Then figure out the pinout compared to the 6N138.

If it all seems too hard, then you can send me 10euro, $10 US or $15Australian (cash) and I will send you 2x6N138's. But you would be better off finding a supplier that you can order replacements from if you need them. (and I have a reputation for being slow to put things in the post! :-[)

where are you located? there are lots of suppliers mentioned on the 'where to order' page, on-line ordering is possible, and if you don't want to put your Credit card number on-line, then a lot of them let you telephone the number through. (It's a pain for those of us without CC though!)

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search google.com for : 6n138 sample !!

if u look good enough u'll find some free samples ;D!

i did that not long ago, have'nt recieved the parts yet.

i dont even remember where did i ordered from, i think it was something like "fairchild"

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Futurlec has them cheap: US$1.50 each, US$3 postage for <US$30 orders. They also have all the other chips you'll need for MIDIbox modules (CORE/DIN/DOUT/BankStick), cheapest I've ever found anywhere else.

http://www.futurlec.com

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Wow you guys are fast!

thanks very much for the advice. It seems I can't get a datasheet for the replacement, and frankly after reading your responses I don't think it's worth the hassle.

I'll find another store that does have the 6N138 in stead. It's such a cheap part that I don´t even want to bother sending for samples.

Thanks for the tips. I'm amazed at this level of support for a non-profit electronics project.

Now, my friend and I know barely enough electronics to assemble this thing. What we do know a little about, on the other hand, is design. Looking forward to uploading some pics of our kick-ass cases when they're done.

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Looking forward to uploading some pics of our kick-ass cases when they're done

me too!  ;)

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Hi,

After reading this topic, I must say i'am quite amazed that all you guys use a 6N138.

After building 7 core's, 3 did work with this chip and the other four didn't. Then by luck I changed one of the not-working core's with the 6N139, and they all happened to work then right-away...rather strange...and can't find the reason too....

Just a tip...try more compatible chips...

Grtz...

Zzzz....

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I had the same problem 2 years ago to find de optocoupler 6N138 to make a PC-MIDI interface, I found and use the 6N139, and works fine!!, it cost to me about 1.1 USD.

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I use 6N136 in my  PC-MIDI-adaptors (MIDI-cables) for a long time http://www.pluslab.ru/docs/AMK-03.pdf

There are no great differences between 6N138 and 6N136. It's only in Boad rate. But 1MBoad of 6N136 is more than enauf for this application. And I think 6N136 is appropriative for MIDIBOX.

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