can someone please help elaborate if a bad cap will affect time / clock functions. My fancy coffee machine has a preset pour for espressos's all of the presets are way out of wack what use to be 25 seconds is now 12.
I am about to replace the psu caps but need some guidance if a bad cap would slow down or speed up clock functions?
Use2bavolvo
Member
Last Activity: 03-19-2024, 05:31 PM
Joined: 01-18-2023
Location: Burnaby,bc
-
Bad Caps affect on time / clock functions
-
Re: Magic chef oven - thermistor ref voltage issue
Power board 2x 1000uf 35v
Power board 1 47uf 25v
Ic board 1 47uf 25v
Ic board 2 4.7uf 35v
Attached component bought from mouser. I bought the 4 relays but didn't install them. These become unobtainium so figured best get spares.
I agree with your comment about the disposable appliance. These things are dead simple devices which should be repairable but most die within 5 years.
My appliances are all analog so they have survived a long time dryer is circa 1993. Only... -
Re: Magic chef oven - thermistor ref voltage issue
Update of everyone.
I replaced 6 caps
3 on power board and 3 on logic board
Happy to report oven is fixed
Recap - thermostat was correctly measuring 1060 ohms at room temp
Oven temp would register 300f at room temp
Relays would come on when temp set to 515 and will get to 350 but wouldn't stay there.
Measured VDC at thermostat connection to the board ~3.8 or lower vdc. With thermostat disconnected 9.8v
The thinking was the ref voltage was low so...Leave a comment:
-
Re: Magic chef oven - thermistor ref voltage issue
Parts ordered was able to get the 4 relays as well. Wil update after I get em soldered in. I wasn't able to get current trim on the caps so just went with uf and v plus length which were requirements for the in between board caps.Leave a comment:
-
Re: Magic chef oven - thermistor ref voltage issue
Looks like we may have found the issue..these caps in macro look buldged out. Digikey didn't have this form factor they are height of 6mm 4.7uf 35v...Leave a comment:
-
Re: Magic chef oven - thermistor ref voltage issue
After reading about capacitors when degrade creates resistance on the circuit I'm gonna replace the power caps to ensure this is generating a stable voltage. 30y its due.Leave a comment:
-
Re: Magic chef oven - thermistor ref voltage issue
R4 is open no resistance
Back of board traces
Second board pic
Also transformer between
pin 1-4 142ohm
pin 8-5 175k ohm
Diode 4 and 5 both registered .526 but when tested other way around went up to 2.0 then 0 not sure if that's from the transformer??...Leave a comment:
-
Re: Magic chef oven - thermistor ref voltage issue
The resistor is between the relay and fan pin. I did some more research it looks like a fuse resistor does that seem right?Last edited by Use2bavolvo; 01-20-2023, 12:38 AM.Leave a comment:
-
Re: Magic chef oven - thermistor ref voltage issue
Model C9875VRV
Control Board part number 7601P225-60
The top board has 3 separate single layer boards this top board does not have any other components just traces.
Middle Section is where the IC is
Bottom Section is for the controls and display
The thermistor is reading correctly at room temp and when hot.
The R4 resistor is a bit of an oddity I read it as Violet, Yellow, Yellow, Red, Red which is a odd ohm 744k (there is no resistance across this) Can I just...Last edited by Use2bavolvo; 01-19-2023, 06:42 PM.Leave a comment:
-
Magic chef oven - thermistor ref voltage issue
I am having an issue with my wall oven temperature control is ~180f out of spec. The thermistor is measuring correctly but I noticed the ref voltage appears to be off. With the thermistor wires attached it's reading ~3.4vdc with the thermistor disconnected it's around I9.8vdc. my understanding is the temp is read off the resistance from the thermistor which leads me to believe the issue is with the ref voltage.
Another observation is the temp setting and readout at lower temps is way off meaning the oven thinks room temp is 300f and bake relay doesn't engage unless temp setting... -
Re: New Members - please post your introductions here
Hello fellow fixers looking fwd to joining and helping grow tinkerer's keep their stuff going.how y'all finding local parts and components storefront in your cities holding up? In vancouver there 1 left. Looking fwd to learning from y'all as we work through issues. Nothing more rewarding than keeping stuff out of the landfill and resolving a issue with a .07 partLeave a comment:
No activity results to display
Leave a comment: