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 Post subject: A replacement for a 2SA70 germanium transistor..PNP
PostPosted: Sep Fri 14, 2018 4:46 am 
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Joined: Dec Tue 08, 2015 12:53 am
Posts: 327
Location: shirley NY...Long Island
Hello...is there a good replacement for the 2SA70 transistor???

I know I can buy them, or it online, I was curious about it..

I have a Sony..a TR-911 that once in a while the volume gets lower, and I either lightly tap on the trans....or take a lighter and warm a screwdriver and touch it on the case of the trans..I believe it is the Mixer trans X2...not sure.

I could show a location pic if someone needs it


Thanks All ........Kenny KE4HVE


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 Post subject: Re: A replacement for a 2SA70 germanium transistor..PNP
PostPosted: Sep Fri 14, 2018 5:42 am 
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Joined: May Wed 01, 2013 10:05 pm
Posts: 1812
Location: Rayleigh, BC, CANADA
That's one of those TO-7 packages where the fourth lead is tied to the case for shielding.

read somewhere they were often prone to failure.

I used to have some AF117 that were good subs for that application.

you can still get them: https://www.ebay.com/itm/2SA70-Original ... 2218222960


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 Post subject: Re: A replacement for a 2SA70 germanium transistor..PNP
PostPosted: Sep Fri 14, 2018 5:50 am 
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Joined: Sep Tue 30, 2014 6:08 am
Posts: 3043
Location: The Old Dominion VA 23518
Follow Sony's recommendation: Use a 2SA341.

https://www.ued.net/ued/viewItemAction. ... e=SNY2SA70 But, NLA from Union (who list ALL Sony parts, regardless of age!)

2Sa341's:

http://talonelectronics.com/shop/item.aspx?itemid=1269

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Brian
"Capacitor Cosmetologist since 1979"
USN Retired 1984-2006 (Avionics/Cal)


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 Post subject: Re: A replacement for a 2SA70 germanium transistor..PNP
PostPosted: Sep Fri 14, 2018 11:55 am 
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Joined: Jan Thu 14, 2016 9:29 pm
Posts: 19
Another good replacement is the OC170. It's easy to obtain, and has the same pin-out and case style to maintain appearance (if that's important to you).


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 Post subject: Re: A replacement for a 2SA70 germanium transistor..PNP
PostPosted: Sep Fri 14, 2018 6:54 pm 
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Joined: Dec Tue 08, 2015 12:53 am
Posts: 327
Location: shirley NY...Long Island
$17 plus shipping...I dont think that is right...I can see maybe 8-10$

Does anyone think the 2SA455, 456 will work???

Yea yea I know, if I want to get it fixed it doesn't matter the cost..

KNY


Last edited by Kennynva on Sep Fri 14, 2018 7:21 pm, edited 1 time in total.

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 Post subject: Re: A replacement for a 2SA70 germanium transistor..PNP
PostPosted: Sep Fri 14, 2018 7:18 pm 
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Joined: Sep Tue 30, 2014 6:08 am
Posts: 3043
Location: The Old Dominion VA 23518
Kennynva wrote:
$17 plus shipping...I dont think that is right...I can see maybe 8-10$

Yea yea I know, if I want to get it fixed it doesn't matter the cost..

KNY


Not sure what you are referring to with the $17 (I posted the one where they are 2 bucks, not sure on shipping.....)

And I thought I'd share some more Sony suggested replacements for the 2SA germanium types:
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Sony2.jpg
Sony2.jpg [ 61.41 KiB | Viewed 103 times ]

Attachment:
Sony.jpg
Sony.jpg [ 59.57 KiB | Viewed 103 times ]

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Brian
"Capacitor Cosmetologist since 1979"
USN Retired 1984-2006 (Avionics/Cal)


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 Post subject: Re: A replacement for a 2SA70 germanium transistor..PNP
PostPosted: Sep Sun 16, 2018 4:27 am 
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Joined: Aug Wed 24, 2011 4:35 am
Posts: 4091
Location: Sunnyvale CA
Kennynva wrote:
Hello...is there a good replacement for the 2SA70 transistor???

I know I can buy them, or it online, I was curious about it..

I have a Sony..a TR-911 that once in a while the volume gets lower, and I either lightly tap on the trans....or take a lighter and warm a screwdriver and touch it on the case of the trans..I believe it is the Mixer trans X2...not sure.

I could show a location pic if someone needs it


Thanks All ........Kenny KE4HVE



A Russian NP416a should work, or an NTE160. This application is particularly undemanding. I am at least a little skeptical that the transistor is the issue, I would look at intermittent soldering or cracked traces, but you could be right. Usually, when they short out from tin whiskers, they just don't work at all.

Brett


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