Phihong PSM-5314 PSU TT Recap

[Steve]

Service blog for this PSU recap using Exxos kit for customer.
New cap kit:

PXL_20201013_093111794.jpg

PSU casing:

PXL_20201013_093114662.jpg

PSU before recap:

PXL_20201013_104557149.jpg

PSU after recap:

PXL_20201013_113828560.jpg

PCB underside:

PXL_20201013_113840466.jpg

Finished, with old caps in a bag:

PXL_20201013_114832246.jpg

Will run some tests on it later.

[Steve]

Tests ok:

PXL_20201013_155924947.jpg

PXL_20201013_155954667.jpg

[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.

[Steve]

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?

[czietz]

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.

[Steve]

Thanks @czietz, I've placed an order for this new optocoupler. Seems to be a good idea :)

[exxos]

Be interesting to see before and after ripple... But also dips in voltage when the floppy drive motor turns on..