fairchild find?

hi, i just found these little black boxes full of semi's that i remember buying at a yard sale when i was a kid - mostly because i think they "looked expensive"

anyways, in each box there are:

1 x AY9171
1 x AY8171
1 x 2N3638A
1 x 2N3643
1 x SE4010
1 x 2N4250
1 x 2N3565

and i have two matching boxes...

the base of the box states that the AY9171 is PNP and the AY8171 is NPN and they are rated at 35W Max. Power T.C 25'C

basically - what can i do with these?

i assume it woudl make a great stereo 35W amplifier module, but i have no schematic, nor do i know how to create one?

any advice woudl be good,

if they are junk - i will forget about it, but if they are not 'junk', it could be a worthwhile project?

attached is pic


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With those thermal coupling clips I'll bet it's the semiconductor compliment to build an amplifier (or perhaps some other device) documented in an application note or magazine article someplace. The intended circuit showcases the capabilities of some recently-introduced (at that time) component. Would be REALLY cool (and a potential museum exhibit) if you could locate the documentation that goes with the parts.

With the styrofoam packing materials, this is OBVIOUSLY before anybody got concerned about ESD. My guess would be late 1960's.


(Does this get the week's award for thread necromancy?)
Hi dChisholm,
The amplifier was presented in an Australian hobby magazine to build in Dec 72/Jan 73, to showcase a transistor complement newly introduced by Fairchild. The transistor 'pack' was sold direct by Fairchild in Australia at the time. I do have a copy of the original mag article but it does not have detailed app notes for the transistors themselves. I can't post these to this forum however. The device list in the OP posting is correct.
Necro-posting twice in the same thread…. I doubt it’s a record, but doesn’t happen that often.
Anton, if you still needed an AY9171, the RCA versions can be found on electronicsurplus.com. They have a lot of the old RCA types like the 2N5955 in TO-66’s, if you didn’t already go ahead and stick TO-220’s in there. Sometimes when I’m working on a vintage piece I want to find TO-66’s to keep the original look, even though MJE1503x (or even heaven forbid TIPs) would be an instant upgrade in most cases. The specs listed above are nothing to write home about today, for sure.
It would be nice, even if only a curiosity, that some Australian member posts the Playmaster 136/140 schematics which used them.

Completely obsolete, of course, but it would put some perspective on them.

As a side note, just read that end of Tariff protection murdered local Semiconductor factories, including Fairchild ... which is being described as an "improvement" :rolleyes:

So pedalling backwards from an Industrial and Technological Country to a mining raw ore based one surely must be hailed as a "good thing"?

Oh well.

top exports of Australia are Iron Ore ($67.5B), Coal Briquettes ($51.5B), Petroleum Gas ($34.1B), Gold ($25.4B), and Aluminium Oxide ($5.6B)
:rolleyes: :rolleyes: :rolleyes:
Joined 2010
Paid Member
There were once scans of the EA articles at "World Radio History" site, plus an update article for Playmaster 136 power transistors dated July 1974 issue of "Electronics Australia" magazine, where Fairchild themselves, suggested replacing the TO66 power semis with SOT32 (TO126?) types 2N4232 for AY8171 and 2N3740 for AY9171 respectively. No doubt, the AY types were by then obsolete.

https://archive.org/details/EA1974/EA 1974-07 July (inc)/page/n49/mode/1up
Apparently Silicon Chip Magazine, owner of the Electronics Australia Magazine copyright, threatened legal action against "American Radio History" for breach of copyright by publishing scans of the EA articles. These had previously been published in DVD form by Silicon Chip. The single US archive though, is vast and comprehensive, has high quality images, is easy to use and available as required anywhere - virtually free. Putting a price on historical media by blocking access is a cruel blow to hobbyists, old timers jogging their memories and curious students who may only browse a few times, to gain an overview or reminisce how solid state DIY was done 50 or so years ago. I doubt the DVD sales are significant now or ever will be again, since it was released many years ago.


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Here’s the article.


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