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Forum Index : Electronics : Looking for AC187/AC188 transistors....

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Grogster

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Joined: 31/12/2012
Location: New Zealand
Posts: 10034
Posted: 05:38am 23 May 2026
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I have an old 70's amp here(PYE 554-P radio-gram), with blown output transistor pairs on both channels, so I am looking for two each of AC187 and AC188.

I understand these are EXTREMELY rare these days, so I am happy to consider equivalents if anyone knows of sets that could be used.

They are Germanium transistors, so need to be the same type because the bias of the amp will be set for 0.2v Germanium type, and standard silicon with 0.6v would require adjusting the bias, and it appears to be fixed on this amp - no bias trimmers.


Smoke makes things work. When the smoke gets out, it stops!
 
Godoh
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Joined: 26/09/2020
Location: Australia
Posts: 704
Posted: 06:14am 23 May 2026
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Seems to be some on ebay

AC187


AC188
 
Grogster

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Location: New Zealand
Posts: 10034
Posted: 07:42am 23 May 2026
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Yeah, but I don't trust ebay.  
Many of their parts are FAKE.

I want GENUINE replacements.

But thanks for posting!  
Smoke makes things work. When the smoke gets out, it stops!
 
Revlac

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Joined: 31/12/2016
Location: Australia
Posts: 1304
Posted: 08:03am 23 May 2026
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Apparently there are a few forums around that play with this old gear.
Not sure if its much help, it links to another page etc.
https://www.vintage-radio.net/forum/showthread.php?t=188664
Cheers Aaron
Off The Grid
 
Pete Locke
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Joined: 26/06/2013
Location: New Zealand
Posts: 186
Posted: 10:00pm 23 May 2026
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Michael Dranfield would be worth asking.
Cheers
Pete'
Hokitika.
 
Grogster

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Joined: 31/12/2012
Location: New Zealand
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Posted: 11:48pm 23 May 2026
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Lovely, thanks.  
Smoke makes things work. When the smoke gets out, it stops!
 
Solarnewbie
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Joined: 30/10/2017
Location: United States
Posts: 12
Posted: 11:46am 02 Sep 2026
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Best I can do.
 
InPhase

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Joined: 15/12/2020
Location: United States
Posts: 182
Posted: 11:28pm 02 Sep 2026
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It's probably easier altering the bias network to use silicon than it is to source authentic working replacements.
 
Grogster

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Joined: 31/12/2012
Location: New Zealand
Posts: 10034
Posted: 12:14am 03 Sep 2026
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Thanks, guys, but the deal is done and finished, and the customer took the amp back after paying an evaluation fee that I charged to look into this issue, so I no longer have the unit.
Smoke makes things work. When the smoke gets out, it stops!
 
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