F34 error. It died slowly over a couple weeks with the same error every few days, until …
F34 error comes up after a minute or so.
Tried toggling & turning off breaker for 15 mins, N/C.
Changed out fan with Hall effect sensor, 00440604. N/C.
Next, relay control board? 00427198.
Any particular component on board worth testing? All diodes test good. Caps all look healthy. No smelly resistors or the like. No bad wires that I can see.
Thanks,
Based on the information you have provided, the relay control would be the cause of failure if there is not a damaged or loose wire. Bosch 00427198 Relay (AP3853433) - AppliancePartsPros.com
thanks for getting back William.
If there was a “hidden” damaged wire to be sought out, most likely in the convection fan area or where the control and display boards are?
Unfortunately, it could be either and testing the wires or checking the wires all over for any indications of damage would be the only sure way of knowing.
OK, thanks again. William
Checked for continuity on the thermal fuse button as well as the wiring that was easily traceable. Nothing was obvious wrong or damaged.
I did give a little whack to K4 on the relay board as that is apparently the relay that throws the F34 error.
I also removed the display frame and examined the PCB that goes with it. The caps all looked good though there was a fair amount of dirt on the PCB in general.
Of course reassembled, nothing had changed. Wondering if the display pcb could possibly throw the F34 error. Seems unlikely, but appliance is not my wheelhouse.
checking all possibilities.
If there was not a broken wire, the only control that would cause this issue would be the relay board.
thanks again.William.
No chance it could be the interior sensor? 00425301
The only wires I haven’t viewed are the connects to the heating elements themselves.
Hi William
Attached are pics of the screws that hold the Hall Effect device, encased (I assume) to the fan.
I’d thought they are Torx, but T10 is a teense small and T15 is way too big.
Any idea what this is?
I want to try changing the Hall Effect device as that seems a possibility. heh, heh, heh. Maybe
nevermind, there is no way to get at the HE sensor. It’s an a-i-o manufacture of the fan.
checking the Hall Effect device on the blower fan, supply and signal lines, I get 18vDC for supply and 2vDC for signal.
Any idea if these voltages are correct?
Supply voltage seems high to me, I’d expect 5vDC, but I tech in pro audio, some perhaps this is correct?
What would the correct voltage be for the signal line?
The 18VDC supply to the sensor and the 2VDC signal return are correct for this appliance. Since the hall sensor of the blower fan is operating properly, the control would be the likely cause of failure.
Thanks for your help William.
By control, do you mean the relay board or the display panel?
I have swapped out the relay board.
If there were damaged wires, is there a particular place in the box that might turn up?
I have carefully inspected and continuity checked wires in the plenum area with the relay & display. Of course, in swapping the relay control, I have inspected connectors as well .
The relay control 00427198 would be the control in question. However, if it has already been swapped out with a new relay control of the same part number, either the relay control is faulty or there is an issue in the wire/wire connection of the harness where the relay control would receive the 2VDC signal.
P6 on the relay Control board.?
Since K4 must be closing to start the blower, might it be an issue with P14 not sending 24vDC to the double-line break relay coil?
Or is the 2vDC signal the priority?
Off hand, the next stop for the 2vDC is a microprocessor or something simpler?
Weird, when I swapped out the relay board there was no difference.
The 2VDC is the priority indicator in this. The 12VDC runs from the relay control to the hall effect sensor, supplying it with voltage that is dropped down when the fan is operating. IF the hall effect sensor is operating properly, it drops the 12VDC down to 2VDC and sends it back to the relay control to signal that the fan motor is operating at the correct speed. Since the sensor is sending the 2VDC back to the relay control at connection P6 (indicating the blower fan is working properly), and the error indicates an issue with the cooling fan/sensor circuit, it leaves only two possibilities. The contacts in a molex connector can spread away from where they make contact to the control, a wire can possibly have a hairline break, or the relay control could be faulty. I would personally double check the wire and the contacts on the control to see if there might be any indications of a loose connection. From there, since the wire itself had continuity, I would believe the control would be faulty if everything else checked out good at that point.
thanks for the detail, William. Quite familiar with contact spread over time with Molex. Faced that a lot in analog recording studios. Will check wire and connect at control.
Weird to weirder.
Found the signal wire (white) loose in the Molex socket. Popped it and gently added a little more tension to the contact area. No sign of oxidation or grime. Clicked back in.
Powered up and tried it. 2vDC making it to the other side of the Molex pin on the board, in front of a 2000Ω (?) resistor (red, black, brown?) can’t find schematic.
Eyes and photo, not clear. C25, Ω, Ω, small glass diode.
F34 at ~40s.
Because I don’t take no for an answer, opened the 220 J-box. That all looks lovely. Opened the breaker panel and checked. No signs of ugly. Flicked the breaker a couple times.
Tried again, ~40s F34. Reset, this time ~50s F34. Reset, this time ~1:30 no fail.
Not wanting to look a gift horse in the mouth, waited til today am.
Turned on. It ran with no issue for ~2m and heard K8 & 9 cycle.
Too hot here to give it a longer try. Tmrw am or late tonite.
But the slow intermittency kind of self repair? Weird.
Or is it not weird?
In tape machines and audio consoles, weird is to be expected.
tried again today. Was on for 15m with cycling K8 & 9 heard.
I guess the Molex pin was the issue. Hopefully our oven is happy.
Thanks for the suggestion Wiiliam.
