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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 Adding images to an existing question

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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.

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@robertsumm76795

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

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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

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Robert Summers will be eternally grateful.
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