Author Topic: 30-180v power supply only outputs 9v  (Read 318 times)

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Offline Brad808

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  • Country: ca
30-180v power supply only outputs 9v
« on: January 23, 2020, 07:47:38 pm »
I just got a Sencore ha2500 that was sold as working but unfortunately the power supply section is faulty. When turned on it will only go up to 9vdc. When working properly it is a variable 80 watt power supply from 30vdc-180vdc.

https://youtu.be/HaU9DDe1eXU

Power supply troubleshooting is far from my strong point so I'd like some guidance if possible.

Here are some pics of the supply. I've tested a few diodes and transistors but they are testing fine from what I can see. I'd like a shove in the right direction.

There are some test pins around the board and I can see 300v at the 3N100e. It's getting quite hot on the heatsink. Not sure if that is the point of failure.

https://imgur.com/a/OGIyDXA
 

Offline Chris56000

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Re: 30-180v power supply only outputs 9v
« Reply #1 on: January 24, 2020, 12:18:38 am »
Hi!

I've not found the original instructions for this yet, but here are the circuit diagrams!

Chris Williams
It's an enigma that's what it is!! This thing's not fixed because it doesn't want to be fixed!!
 

Offline Brad808

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  • Country: ca
Re: 30-180v power supply only outputs 9v
« Reply #2 on: January 24, 2020, 12:30:11 am »
=-O Whoa thanks! That's going to be insanely helpful. I could barely find a user manual for it I thought a schematic was wishful thinking.
 

Offline Brad808

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  • Country: ca
Re: 30-180v power supply only outputs 9v
« Reply #3 on: January 24, 2020, 10:47:39 am »
I think I might be on the right path now. When I went to measure these diodes/ (fuses?) Inside the heatsink near the transformer they basically crumbled in half. The appear to be input protection on the primary side of the xformer. I'm going to order 2x sa150a, 2x mur1100e to replace all of them on that path and see what I get.


[https://i.imgur.com/Lilu4EF.jpg](
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