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HR2510 Dead Short Ideas??????????????????????????

Since the final is bolted directly to the chassis, the caps are needed for impedance matching. When you isolate the final from the chassis, you no longer need to use the caps to match the impedance, since the impedance mismatch is removed by isolating the final off the chassis.

And you're welcome. Glad to help out. (y)


~Cheers~
 
What about the glue/sonybond or whatever is called after so many years (can hold moisture) and became conductive and corrosive creating shorts and will eat the pins or connections ?
 
@nomadradio - Message #9

I forgot to mention 8V regulator and protection diode were checked.

But then too, you're testing for Continuity - so the VOM will act differently than a higher scale resistor reading check.

Some meters even reverse the polarity of their leads during this test - for even the 9 volt battery can blow parts on the board - LED's as well as different Zeners and small SMD resistors can blow from the current the typical DVM of just a few years ago can send thru the leads. Analog meter types can do that kind of damage too.

The main problem you're seeing @Low_Boy - is the very thing you posted about - the caps.

Some are pretty huge, as you find out - so they tend to take in all the current - but you have at least 25 larger value Electrolytic's in there awaiting the other 24 to recoup a charge which isn't going to happen for a long long time while you're busy trying to figure out why the VOM is acting this way - they are simply, greedily, current monster - munchers accepting what the DVM put out and are asking for more.

Part of this problem? The 7808 - when it's waiting for power, there is a special low-cutout circuit that allows the device to be passive when there is not enough power to regulate. So when the voltage falls below 8~9 volts - the threshold to operate isn't there - so the device acts like a short - but it's not - it's the cutout working to protect the parts on it's output side.

upload_2020-5-6_8-56-2.png
Inside the 7808 is a reverse biased Zener - it's there to protect the input from reverse polarity and overvoltage - you can see it in action if your leads on the continuity checker "reverse their polarity" for testing. You're seeing the internal zener as well as the cap charging - at the same time and the meter shows you a short because of this.

There's lots of stuff going on - but I'm glad you take the time for that procedure - for many don't and suffer catastrophic failures from the "patient" surviving the surgery - but dying on the table during the power-up procedure...

frankenstein-its-alive-scene.gif
 
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