Author Topic: Some advice on temp and help understanding  (Read 641 times)

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Offline Bensco

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Some advice on temp and help understanding
« on: June 15, 2019, 03:57:39 pm »
Hi, I picked up an old technics sa-eh760 hifi system, it works great. I have a concern with a component getting very hot, it's a pcb with 3 transistors d2374 and 2 b1548's the service manual calls them regulator transistors. The 3 transistors are clamped down to the body of the amp, I'm guessing for heat dispersal. If it is a heat sink it's not very substantial and no sign of any thermal paste ever being used. So I would like to know what it is? A voltage regulator?
And should it get hot? How hot is to hot.
Many thanks Ben
 

Offline soldar

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Re: Some advice on temp and help understanding
« Reply #1 on: June 15, 2019, 04:03:42 pm »
Complementary transistors. 2SD2374 , 2SB1548
« Last Edit: June 15, 2019, 04:05:22 pm by soldar »
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Offline Audioguru

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Re: Some advice on temp and help understanding
« Reply #2 on: June 15, 2019, 05:56:22 pm »
The service manual with a detailed schematic was posted on the other website's forum.
 

Offline soldar

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Re: Some advice on temp and help understanding
« Reply #3 on: June 15, 2019, 07:40:08 pm »
Yes, I found it easily online. After a very quick look it might be that those transistors are not part of the audio amplifier but part of the power supply. I did not look in detail though.
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Online Stray Electron

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Re: Some advice on temp and help understanding
« Reply #4 on: June 15, 2019, 07:44:02 pm »
  I would look for any capacitors that are on the output of the regulator circuit (or on the input to the audio amps which it powers) and check and see if any of them are starting to short out.  They could be drawing too much current and overloading that regulator.
 

Offline Bensco

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Re: Some advice on temp and help understanding
« Reply #5 on: June 15, 2019, 08:02:21 pm »
Thanks for the replies
 


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