Whirlpool dryer control board

[Eaglecrest]

I have a Whirlpool dryer that runs for a while then stops with a blinking timer screen. The dryer can't be reset by hitting any input and if you pull the plug and plug it back in it also won't respond. Light is on in the drum when you open the door, but no other sign of life. If I leave it unplugged for a period of time, which is multiple days, it runs again. May be able to get a load done, but now seems to be less than full load before it errors out.

Since unplugging will get it to work, I am assuming that there is an error condition that is causing the onboard processor to shut down the dryer (condition stored in memory) and then removing power lets the circuit drain and causes a reset. There is no error code given and checking on line the blinking screen seems to indicate a control board failure. While many things could be causing this, I looked at the board and there is a burnt pad under the relay. I don't recall this earlier, even though the same problem existed; however, at that time power resetting could last for weeks to months, so I am thinking that whatever is happening (bad solder joint?) has gotten worse and that is why it now works but only for a short time after reset.

Does this seem to make sense from an electronics POV? If the joint is bad can I run a wire from the relay lead to the power connector, in effect replacing the trace with a wire connection?

[stj]

that could have been caused by bad sofering OR bad relay contacts.
either way, you have to remove the relay,clean the board and ideally fit a new not-cooked relay.
otherwise the control board will know the motor isnt being powered.

[Eaglecrest]

If I understand your comment correctly, if the relay is bad then hard wiring it won't do much/anything. I would assume that a relay will either work or not and since it does work after reset it seems like to issue isn't with the relay. If there is a poor connection and depending on what the controller chip is monitoring I am thinking that it is reacting to the damage to the trace and that is what is causing the error/failure. Again, assuming that the trace is the cause then I am thinking that if I hard wire from the relay post to the power post (exactly what the trace does) then I should be offering a better path for the circuit and it should work. Is this reasonable thought?

[stj]

remove the relay and sand/ file the contact and check the case isnt melted around it.

[Eaglecrest]

I appreciate your advice, but you aren't answering my question. I don't see why I would need to remove the relay. It seems to work fine, when the board works. I would assume that a relay either works or it doesn't. Why would a relay work for a while, then stop and after "resting" work again?

Additionally, I purchased a used replacement board that had the same problems. Close examination of this board showed it had the relay replace and it appears that when the relay was replaced the trace I am asking about direct wiring was damaged and soldered to repair it. So I am guessing that if the trace has an issue it will cause the controller chip to see an error and shut down the system. It seems the best way to test this out would be to run a wire directly from the relay post to the power connector post, which is what the trace in question connects. So the question at hand is if there is any reason to believe this would work or would cause a problem. I don't see why, but am asking for advice from people wiser than me.

Stated another way, if the problem is the trace then I can replace as many relays as I would like and never fix the problem.

[stj]

most likely if you have 2 with burned pads the relay is burning inside and the heat from that is burning the pad.
it needs a better quality ore higher current relay.

[CapLeaker]

Same as: if a relay clicks when energized, doesn’t automatically mean it is good. As far as that black spot on the PCB: take the coating off, unsolder the relay, check these relay by energizing and de-energizing the relay and checking the resistance while doing so. Clean the board resolder the relay if it is good or replace with a new relay, if you aren’t sure. Verify the PCB ais working and go from there.

[Eaglecrest]

Why can't someone answer the base question? I can appreciate that the relay may well be the cause and to really fix this the relay may need to be addressed, but is there a problem if I hard wire to make sure the problem is the relay and not the trace?

[R_J]

There is nothing wrong with hard wiring the burnt trace, it is done all the time that is likely all that is wrong, clean the relay pin so you can make a good solder connection to it. Resolder any other similar large connections adding more solder as required,

[stj]

i think he is refering to bypassing the relay.

[R_J]

Looks like the relay is for the Motor, It looks like a common problem with that connection going bad, I would repair the connection like I suggested and it will likely solve the problem. it looks like it is a 30 amp relay

[Eaglecrest]

STJ, don't know how you got your understanding. I thought I was quite clear that I am looking to deal with a bad trace between the relay and the power connector. Bypassing the relay would have the motor running full time regardless of the setting. I don't see how that could possibly be a good idea. You never asked for clarification nor mentioned that would be a bad idea, if that was your thought.

[Eaglecrest]

R_J, that is my understanding. A couple of followup questions. Would an 18G wire be sufficient?

As I look at the schematic, it seems like when energized the relay turns on the motor. It seems like, therefore, if the relay goes bad then the dryer should function in every way, except the motor wouldn't come on and thus no clothes get dried. In my situation, nothing happens. The light inside the drum is on, but the control panel does not come on nor is there any kind of operation other than the interior light. Thus I am assuming that somehow the controller chip is monitoring this and is shutting the system down when the relay fails, does this make sense to you?

To further my thinking, I found a "repair kit" on eBay which is just the relay; as I mentioned earlier, i bought a replacement board that worked the same as my board (runs the dryer for a short period then shuts down the system with a blinking light and no activity with the buttons requiring a power reset). This replacement board had what appeared to be a new relay (different than the relay on my board) and it appeared that the trace got damaged when it was removed as half the distance of the trace from the replay post to the power connector post was solder. I am assuming that the solder repair wasn't working and that was causing the failure after a short system run.

My dryer worked fine for years (at least a decade) and I am further assuming that after years of use the relay power connection weakened the connection to the board and has progressively caused cause the solder connection to deteriorate. I further assume that a relay will either work or it will fail so it seems that the problem is more likely the connection from the relay to the power strip than the relay itself. Do all these assumptions make sense or am I off base?

[stj]

most dryers use the same motor for the drum and the air circulation fan.
if that doesnt run the heater will get too hot and that will get detected.
if it's an electric heater anyway, gas ones must have a heat exchanger and more safety devices.

[R_J]

Just repair the trace already, the length of the wire is so short that 18 gauge would be fine, it is very likely that that relay pin did not get enough solder when manufactured, so over time the connection weakened and once it got loose started to arc, Install the jumper already and try it. If you want to replace the relay go ahead and do it.

Like I already said, resolder ALL the relay pins and also the connector pins as they usually do not get enough solder when they are made. If it is the Omron G8P-1A4P, here is the service life for that relay

[Eaglecrest]

I had a difficult time getting the old solder off. I needed to go to about 410 degrees to get it to melt. That seems rather high, but it was what it took. I was able to get the power strip connectors cleaned, but the relay never came clean. I used a solder sucker and copper braid, but I never seem to be able to get the braid to work. Thoughts and suggestions regarding these observations?

So I soldered a stranded 16G wire between the two points and the board is completely dead. Previously it would startup, but then die shortly after use. The power connection to the other end of the wire showed continuity, but there is no way to check if the relay is actually getting power. Not sure if there is a problem with my solder job or if the heat caused an issue with the relay. Seems like a relay shouldn't be too delicate. Any thoughts on this result?

Seems like a stranded 16G is over kill; I am thinking that I would be better with a solid wire would be better that could be put into the through hole next to the post and that should be a better solution. I am assuming that i need a reasonably significant gauge to carry the needed current, how do I determine the appropriate gauge?

I have ordered a new, used board which should at least get the dryer up and running again, but I would like to play with the old board and see if it can be revived. Suggestions/insights would be appreciated.

[R_J]

Without any pictures of your repair job, it's hard to comment. the trace connection to the relay was not making connection, if it didn't get soldered properly the fault would be the same, the heat would not have hurt the relay. check your solder connections, check that you connected everything correctly

[Eaglecrest]

Here are some pictures of the job, not pretty, but I am getting continuity from input post to the wire joint at the relay. So that solder job worked. Can't tell if the relay is making contact, but don't understand why it wouldn't. Your confirmation that relay should not suffer from the solder work means that it is dead because of that solder joint. I can try to reflow and add more solder. I used 60/40 solder and it seems like it was lead free solder originally, it was my understanding that mixing them shouldn't be an issue. Is this a wrong understanding?

Not sure I am understanding your comment, "the trace connection to the relay was not making connection". Regardless of the trace connection, the wire parallels that connection and will either replace it or combine with it. So as long as the wire makes a connection to the relay post all should be well.

[R_J]

What I am saying is that trace repair should not cause the board to be dead, you must have done something else, if you remove the wire do you think the board will start to work as before? the wire only replaced the trace it did nothing else. Maybe there are other poor solder connections on the plugs.

[lotas]

Did you connect all the wires correctly and didn't mix anything up?