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Phihong PSM-5314 PSU TT Recap

Posted: Tue Oct 13, 2020 2:04 pm
by Steve
Service blog for this PSU recap using Exxos kit for customer.
New cap kit:
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PSU casing:
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PSU before recap:
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PSU after recap:
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PCB underside:
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Finished, with old caps in a bag:
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PXL_20201013_114832246.jpg (394.98 KiB) Viewed 620 times
Will run some tests on it later.

Re: Phihong PSM-5314 PSU TT Recap

Posted: Tue Oct 13, 2020 5:01 pm
by Steve
Tests ok:
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Re: Phihong PSM-5314 PSU TT Recap

Posted: Tue Oct 13, 2020 5:14 pm
by czietz
Note that if this PSU is ever intended to go into a Mega STE, the optocoupler should be changed. Search the older threads for possible replacement part numbers. The optocoupler in the pictured PSU is known to cause 50 Hz output ripple that becomes visible as slight flickering of the screen in the MegaSTE in monochrome mode.

Re: Phihong PSM-5314 PSU TT Recap

Posted: Tue Oct 13, 2020 6:29 pm
by Steve
czietz wrote:
Tue Oct 13, 2020 5:14 pm
Note that if this PSU is ever intended to go into a Mega STE, the optocoupler should be changed. Search the older threads for possible replacement part numbers. The optocoupler in the pictured PSU is known to cause 50 Hz output ripple that becomes visible as slight flickering of the screen in the MegaSTE in monochrome mode.
Thank you for the information. This is TT only. So is the PC111 a recommended optocoupler for both MSTE and TT?

Re: Phihong PSM-5314 PSU TT Recap

Posted: Tue Oct 13, 2020 7:07 pm
by czietz
Steve wrote:
Tue Oct 13, 2020 6:29 pm
Thank you for the information. This is TT only. So is the PC111 a recommended optocoupler for both MSTE and TT?
Yes, it is.

Disclaimer: Of course, like with any PSU work, be sure to re-test with the dummy load after changing the opto-coupler to be sure that the output voltages are correct.

Re: Phihong PSM-5314 PSU TT Recap

Posted: Tue Oct 13, 2020 8:00 pm
by Steve
Thanks @czietz, I've placed an order for this new optocoupler. Seems to be a good idea :)

Re: Phihong PSM-5314 PSU TT Recap

Posted: Tue Oct 13, 2020 8:05 pm
by exxos
Be interesting to see before and after ripple... But also dips in voltage when the floppy drive motor turns on..