whirlpool w10491734 diode identification

[ajshoe]

Have a whirlpool CAE2743BQ0 washer that has this part that has failed. This is called the coin slide interface board. It connects to the main board and coin slide mechanism. I am trying to identify the 6 diodes on this board. A good board the diodes measure 4M ohms. under a microscope the diodes have A2 11 on top. Does anyone know what I can sub for these ? can I just use a 1n4148 ? thanks, John

[jiroy]

Originally Posted by ajshoe

Have a whirlpool CAE2743BQ0 washer that has this part that has failed. This is called the coin slide interface board. It connects to the main board and coin slide mechanism. I am trying to identify the 6 diodes on this board. A good board the diodes measure 4M ohms. under a microscope the diodes have A2 11 on top. Does anyone know what I can sub for these ? can I just use a 1n4148 ? thanks, John

It seems You're measuring the six diodes . Measure only one ..

[ajshoe]

measured each one - each one (all 6 of them) measures 4 Mohm in one direction and open in the other

[jiroy]

Originally Posted by ajshoe

measured each one - each one (all 6 of them) measures 4 Mohm in one direction and open in the other

1N4148 is suitable then ..Just wanted to affirm ..

[ajshoe]

thought so - wanted confirmation before working on this garbage board. hard to believe these go bad. thanks

[jiroy]

Originally Posted by ajshoe

thought so - wanted confirmation before working on this garbage board. hard to believe these go bad. thanks

Good luck Friend ..

[momaka]

Aside from measuring the diodes with resistance test, did you also check them under diode test? I.e. they should show around 600 mV of voltage drop in one direction and open in the other. Still not a 100% confidence test, as they could also be leaky... but at least you will know if they are open or not. 4 MOhms is a really high resistance and not necessarily indicative of anything, even if that's on the working board or not.

If you have once of those transistor tester devices, those are actually fairly decent for identifying bad diodes, because they also show the junction capacitance and reverse current. High reverse current or zero capacitance junction may be indicative of a leaky/dying diode, even if forward voltage is still correct at ~600 mV.

[stj]

what coin mechanism does it use?
just curious how "dark ages" these machines are?

[jiroy]

Originally Posted by stj

what coin mechanism does it use?
just curious how "dark ages" these machines are?

Those are Maytag ..Long life .

[redwire]

It would be rare for these diodes to fail, they must be gutter grade. Hard to test without poking through the conformal coating.
I think they are MMBD4148 or 1N4148W in SOD-123 package. They would be for keypad mux so these coin slot switches are likely involved with other pushbuttons. The MCU uses row/column scanning to read them all, and the diodes prevent "ghosting".
Don't put the new ones in backwards, take a pic with the stripe showing.

[ajshoe]

stripe is on bottom or to the left of D1-D6. You are correct - they are scanned to the main board to read the users configuration (there are 3 wire jumpers on this board). It also reads the coin slide (vertical 8) switch when the coins are inserted and the slide is pushed in. Main board on this machines are a constant failure - they must also burn the diodes up when the main board fails. Unfortunately this is a whirlpool washer and they are complete junk. These washers are not worth fixing- so many things fail on it. old mechanical washers and dryers are the way to go on (commercial) coin operated appliances.

[stj]

amazing.
here we ditched the simplex and duplex slides over 20 years ago - should have been 30 but somebody probably had a stockpile to use.
ditched them from the pool tables too

just electronic mechs now that can identify upto 32 coins of different values.
and they cost less than a duplex did!

[redwire]

Modern Whirlpool appliances seem to be using really cheap parts out of china, the kind of thing that fail when it shouldn't. How hard is it to get a decent diode? I think their supply chain is getting sabotaged so Haijer etc. can take over.

We had not so smart thieves bust the commercial Maytag coin slot/coin shute, they never got in the coin boxes for the gold and diamonds It cost a lot to repair- over $1,000.
I proposed to get rid of all this and go with a debit card or RFID but it appears there are parasite companies wanting a cut and charging a small fortune for the card reader electronics and even more for a banking/debit card terminal.

They're old Maytag MVWP575GW0 washers and the coin slot actuates a lever arm on the main timer/cycle motor. No semiconductors involved. Strictly mechanical.
I hate the machines, agitator is a clothes ripper, transmission clunking after not so much use. Repair parts galore but callouts just add up.
Next time would consider going with Huebsch.

[stj]

the simple answer is to recalibrate the coin mechs to recognise a token and then sell the tokens at the counter.

also, i friend had a laundrette and he removed all the cash boxes and piped all the coins down through the floor into the basement

[momaka]

Originally Posted by stj

also, i friend had a laundrette and he removed all the cash boxes and piped all the coins down through the floor into the basement

As long as the thieves can't figure out where the basement is accessed from, that's a good option.

A couple of years back I worked for a toll road nearby that still had operational coin machines at the toll booths. On the main plaza, there was a tuner under the whole road (6 + 6 lanes.) Coins from the toll booths collected down at vaults in the tunnel. And there was access from the road / toll booths down to the tunnel too. Was also more convenient for the vault crew to pickup the vaults, since they wouldn't have to try to squeeze in a tiny toll booth that was already cramped with the toll collector and could hardly fit another person in there.
Anyways, having worked with coin machines on that job, I am amazed at both how fickle and yet also how robust these machines can be, depending on the circumstances. In our case, being a toll road, you'd sometimes find really "interesting" items thrown into the coin baskets. One of the best was a rare $2 bill. No idea who was the fool that thought a coin machine could read a bill, but I digress.

[stj]

the latest mechs for that type of use are very impressive, one is called "pelican" it has a big mouth
it can seperate and sequentially process a handfull of coins thrown into it very quickly.

i'll never see one other than at a tradeshow though - not my line of work.
https://www.cranepi.com/en/products/...rs/v2-pelicano

[momaka]

Ours were made by some French company that went bust right after selling us the machines... but the coin machines looked and operate just like the one you posted. Basically, you could take almost an entire fistful of coins and dump them into the machine, then watch as it sorted through them. If you dropped too many, it stopped and dropped them in the reject basket, then restarted operation again. Pretty nifty design! Where the French screwed up was the cabinet, particularly the coin reject basket - it had a sharp edge where coins would get stuck and backup, then jam the machine. I found, documented, came up with, and machined a fix for all of the machines on the road. Dropped the number of calls from 100's a day on really busy days to 1-2 max. Needless to say, I worked myself (and a few others techs) out of that job, LOL. (Though that wasn't the only reason why the company cut back on techs, but I digress once more.)

[stj]

i didnt know of any french coin companies.
most are or were british, german, italien or spanish
and AZKOYEN - not sure where they are from

[momaka]

I can't recall the name and I don't have pictures of the machines on this PC, but they were French. Nicely built too, save for a few not-so-service-friendly design decisions. But all in all, they were pretty good once we got the kinks out of the system. The nice thing about them was that they were mostly made of stainless steel - a must when dealing with dirty things like coins, especially in high volumes (some machines would see ~$5k worth in coins per day. ) The one you pointed to above looks to have lots of plastic and nukes and crevices. Would be a nightmare to clean up properly.

Also, the old machines that were on this road (before I came onboard) were some Australian ones from the late 80's, IIRC. Heavy thick aluminum everywhere. Looked a bit like reel-to-reel players with covers on, but otherwise operated on the same principle. Were about 4-5 times bigger and weighted around 70 lbs... so a 2-person job to change one. But they also needed much less maintenance (once a month vs. ... unpredictable for the French ones.) And the swap took about 1 hour vs. 20 seconds for the French ones (sometimes I could do the French ones between 2 customers in the line.)

[stj]

aluminium oxidises, steel rusts.
galvanising wears off.

the mechs are plastic with a very high level of glass-fiber in it.
they are very strong and easy to clean and the surface feels slick like teflon!
they have to be plastic or it would fuck with the inductive and acustic sensors.