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Repair and disassembly information for amplifiers in home audio systems.

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Fuse clearing on power supply

Working on a phillips AH 578 amplifier and need help identifying and testing transistors. I can send photos if needed.

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@robertsumm76795 no reason the send pictures, just add those to your QUESTION. Here is the guide for that Voeg afbeeldingen toe aan een bestaande vraag


In one of my searches I concluded that replacement for q203 and q204 is NTE 269 and 268. These are both darlington and might not be correct replacement. I looked uo 383p1 and 383n2 and they are in a different package m(no heat sink). Also, fuse 12 is shown as 6.3A but my unit has a 15A ceramic and it is clearing.



What is the full model number of the device if the 22AH-578 is not it?


Originally I tried to find replacement parts by examining numbers on components. I ended up buying NTE268 and 269 to replace Q 203 and Q204 on driver board. I don't have any training on solid state components and I only have a volt-ohmeter to check. I am beginning to think the NTE's are not the correct replacements. They are Darlington. Yesterday I looked up 383P1 and 383N2 as shown on parts list but they are in wrong package (no heat sink). Not sure how to proceed. Original transistors have 359-1/m726 and 359-2/m726.


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Hi @robertsumm76795

Here's the service manual for a Philips 22AH 578.

It has most of the schematics showing the type of transistors, a circuit description and a parts list.

Hopefully this is of some help.

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Hi @robertsumm76795,

Found this link showing the equivalents between Toshiba transistors and European ones that may help.

About halfway down the page there's a list in which it shows that a 383P1 = 2SA835 and a 383N2 = 2SC1124.

The examples are only to give an indication of their possible cost and also to show that they have heatsinks ;-)

Maybe worth trying those


Finally getting back to repair attempt. Local electronics store recommended NTE 288 and NTE 190. The 190 has heat sink but the 288 does not so still wondering if they will work.


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