Diode Value Dishwasher

[sebouh]

Dishwasher
Brand: Miele
Model: G5601SCi
Control Board: ELPW 527

The diode near TNY278GN is burned. The other diode is not damaged and is marked SS18A it is rated 80V 1A. The board runs mainly relays 12V.

With what value diode shall I replace the burned one? Will S2K diode (800V 1.5A) be ok? Thank you

[bob91343]

Probably okay.  Try it and see.  Why did it fail?

[sebouh]

According to the technician the top auto open door mechanism is faulty too and since the door didn't open at the end cycle the control board continued to supply power and eventually burned.

They are requesting a fortune to repair but I noticed that both the board and auto door mechanism can be repaired.
I will try to change the diode and let us see.

Thank you bob91343.

[fzabkar]

The logo on the "SS 18A" diode belongs to Vishay / General Semiconductor. My searches suggest that it could be an 18V unidirectional TVS diode. You could determine its actual function by identifying how it fits into the circuit. Is it connected in parallel or in series with a supply?

Alternative search results suggest a Schottky rectifier. The diode you have found is a general purpose rectifier. It doesn't appear to be a legitimate replacement in either case.

https://www.vishay.com/docs/88303/15smc.pdf

The application circuit on page 8 of the TNY278GN datasheet shows two diodes, one of which is a suppressor diode.

https://www.mouser.com/datasheet/2/328/tny274-280-4065.pdf

[sebouh]

fzabkar,

Thanks for your valuable info. Yes, both diodes are connected in series cathode to cathode. While searching on the internet I noticed that on most washing or dishwasher machines boards, one of the diodes is marked "SS" (Vishay manufacturer as you said) and the other diode usually RK06, RK14, RK16 or RS2K. Since RS2K the volatge is 800V i thought to try with RS2K.

I couldn't find S2K diode so I have to order one.

[fzabkar]

I think that the "18A" is a Year/Week date code plus a "factory designator". That is, 8th month of 2011, factory "A". The part code is "SS".

Diodes Group Body Marking - Vishay General Semiconductor:
https://docs.rs-online.com/f177/0900766b81725718.pdf

AFAICT, SS is a 188V unidirectional TRANSZORB Transient Voltage Suppressor (SMAJ188A):
https://www.vishay.com/docs/88390/smaj50a.pdf

The RK diodes are either of the following, depending on the package (800V, 1A, fast switching rectifier):
https://www.vishay.com/docs/88707/rs1a.pdf
https://www.vishay.com/docs/88697/rgf1.pdf

You must not replace these with general purpose rectifiers intended for mains frequencies (50Hz/60Hz).

RS2K is an 800V, 1.5A fast switching rectifier:
https://www.vishay.com/docs/88708/rs2a.pdf

[sebouh]

fzabkar,

Thanks once more time for trying to help me. I will order an RS2K diode and I will try. I do not have other alternative.