Thermador Oven Controler Dim display

[gadgetware]

Re: Thermador Oven Controler Dim display

So checked everything again today. Looks like the only thing they replaced on the board were the capacitors. I found one that was loose and not tracing out properly so I soldered some wire to fix that. Checked all the other solder joints that they did but didn't find any problems. Put control board back in and still the F1 error. Tested the temp sensor again for both resistance (1080 ohms) and ground fault (that passed). Unfortunately I can't get anything other that the F1 error on the screen so can't check what temp it thinks it is.

Didn't check the elements, but I guess I can try that next. Any other ideas?

[redwire]

Re: Thermador Oven Controler Dim display

I see some board damage (lifted pads/traces) by whoever recapped the board but looks OK. It's tagged as a refurb so it is supposed to work?

The oven F1 error doesn't say much other than "replace the board". Thermadoor's website is uselss and says nothing.
Same control board is used in many other ovens like Bosch Thermadoor Whirlpool Frigidaire etc.
So we don't know much about the meaning of this error code. Whirlpool says it's the A/D converter error. Others say runaway oven heat, which would be a stuck on relay.

Apparently F1 error can be due to connections at the corroded wire nuts going to the oven temp sensor: https://blog.fixyourboard.com/2016/0...-on-oven-range
I would be measuring oven temp sensor resistance right at the (unplugged) board connector between pins 3-5 for the around 1085 ohms.

Otherwise I would check the 5V power supply is OK, keypad is OK.
U4 looks like microcontroller Invensys Robertshaw 053-00131-00 DIP-24, and it does get replaced. There is a jungle IC under the display tube not sure of part number.

[petehall347]

Re: Thermador Oven Controler Dim display

i thought jungle chips were for crt tv sets ?

[redwire]

Re: Thermador Oven Controler Dim display

Any shrink-DIP 64 pin MCU, that is HV drives a VFD I call that jungle.
The other DIP-24 MCU is probably a PIC and appears to connect to the Pt1000 temp sensor. I think it has the model-specific features? But the SPI EEPROM goes to the jungle IC.

The same control board is used in many ovens, I hope it's not discontinued that would be terrible.

[toboggan]

OUTCOME: I replaced the four capacitors on the power board. I did not replace the three smaller capacitors on the Vacuum Fluorescent Display (VFD) board due to issues described in the rework section below.. After the change, the VFD brightness is improved enough to read the temperature, but not as good as new, as the upper part of the VFD is still a bit dimmer than the lower part..
REWORK: The board is single sided without plated holes. The original caps have bent leads. Finesse the temperature and wetting, but expect to damage the some pads during rework. The traces are easy to follow and check with a mutimeter. Consider fixing any damages traces with the extra lead length of the replacement caps (prior to trimming).
MY ORDER:
There are the caps I ordered for replacing the old caps. I favored caps with high temperature and long life ratings and low ESR/impedacne. Some replacement values are slightly higher in capacitance than the original. For many uses of electrolytic capacitors a little higher can be good. That said, I don't have the schematic. In many case tolerances are 20% and capacitance drops with age, so hitting the value dead-on might not be so important. The premise here is too low of capacitance results in a dim VFD. I ordered C3, C11, and C14 based on specs found earlier in this thread and neither checked against my board or replaced these caps yet. I made my order from Digikey.

REF | Original | Replacment manufacturer part number
C1 | 3300 uF, 16V | EGPD250ELL362MK30H
C5,C8 | 470 uF, 16V | UBT1C471MPD8TD
C9 | 100 uF, 50V | 50ZLJ120M8X16
C14 | 10 uF, 16V | RXW100M1CBK
C3 | 4.7 uF | EEU-FR1H4R7
C11 | 0.47 uF 50V | 860160672001