Author Topic: power supply replacement  (Read 555 times)

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Offline _THEON_

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power supply replacement
« on: May 24, 2019, 05:07:46 pm »
Hi everyone,

i have an old device with separate power supply which i would like to replace since it does look very worn down and humms.
Since i dont have a datasheet, is there a way to know the max amp rating so that i can find an fitting replacement?
I measured +/- 12 volts at the outputs with multiple +12v and ground connections. Is it safe to assume they are the same?
Further more, there seems to be a floating pin connected to the frame.
Are there any other things that i should look out for?

Thanks in advance.
 

Offline treez

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Re: power supply replacement
« Reply #1 on: May 25, 2019, 08:53:20 am »
to replace the power supply.....can you borrow a bench power supply.?..set it up for +12/0/-12  output and hook that up to your device...then measure the current in the wires to it...and then from that work out what power is used...then buy a power supply of that power level or  more
 

Offline _THEON_

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Re: power supply replacement
« Reply #2 on: May 25, 2019, 09:35:03 am »
Sadly my power supply only has a single output, so i can't provide +12/0/-12  :(
 

Offline Jay_Diddy_B

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Re: power supply replacement
« Reply #3 on: May 25, 2019, 09:54:48 am »
Hi,
Does the original supply have any labels on it?

Can you tell us what is being powered by this supply?

Can you tell us the manufacturer of the equipment?

Regards,
Jay_Diddy_B
 

Offline radix

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Re: power supply replacement
« Reply #4 on: May 25, 2019, 11:27:46 am »
You can try to work out a very approximate upper limit based on components that are in there.
I can see a 2.5 mF electrolytic and a C 5000/3000 bridge rectifier. If I recall correctly, the bridge rectifier is rated for 5 A/3 A and the electrolytic would imply something between 0.5 A - 1 A, or more depending on which rule of thumb you follow (these numbers are for 2-4 mF/A).
 

Offline _THEON_

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Re: power supply replacement
« Reply #5 on: May 25, 2019, 01:41:25 pm »
Thanks for your replies.

I have no information on the device since the manufacturer is no longer around.
The supply drives a CRT.
 

Offline vk6zgo

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Re: power supply replacement
« Reply #6 on: May 26, 2019, 03:57:10 am »
Thanks for your replies.

I have no information on the device since the manufacturer is no longer around.
The supply drives a CRT.

By "CRT" do you mean the entire monitor ?
"CRT" normally refers to the big glass device that your display appears on.
 


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