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Bosch Dishwasher pcb

Baxi

Dec 8, 2021
4
Joined
Dec 8, 2021
Messages
4
Hi Guys,
I've been reading about someone with a similar problem on this forum.
The Dishwasher won't power up at all, after removing the main control board I noticed a resistor with the shell burnt, after removing and testing it found it was open,
I wasn't sure of the value as the shell was burnt but could make out the first three bands- brown, black, black the last two bands were either black and white or gold and white, I replaced the resistor with a 10ohm, when I tried the board on the bench got various voltages as before but when installed into diswasher it poped. Upon inspection found the tny264 chip had blown and also found some marks near a component marked 67 not sure if that was caused by the tny264 as it's in the same vicinity on the board
Please can someone advise
A, if the resistor I replaced was likely to be 10 ohm?
B, if it never poped on bench what else can be causing it when installed?
C,Is it worth replacing the tny264?
D,What is the component marked 67 and how do you test it?
Sorry struggling to upload the jpeg photos any tips would be appreciated.
Thanks in advance for the support.
 

Tha fios agaibh

Aug 11, 2014
2,252
Joined
Aug 11, 2014
Messages
2,252
Hi Guys,
I've been reading about someone with a similar problem on this forum.
The Dishwasher won't power up at all, after removing the main control board I noticed a resistor with the shell burnt, after removing and testing it found it was open,
I wasn't sure of the value as the shell was burnt but could make out the first three bands- brown, black, black the last two bands were either black and white or gold and white, I replaced the resistor with a 10ohm, when I tried the board on the bench got various voltages as before but when installed into diswasher it poped. Upon inspection found the tny264 chip had blown and also found some marks near a component marked 67 not sure if that was caused by the tny264 as it's in the same vicinity on the board
Please can someone advise
A, if the resistor I replaced was likely to be 10 ohm?
B, if it never poped on bench what else can be causing it when installed?
C,Is it worth replacing the tny264?
D,What is the component marked 67 and how do you test it?
Sorry struggling to upload the jpeg photos any tips would be appreciated.
Thanks in advance for the support.
If it was a 5 band resistor, the 4th black band (multiplier) would make it 100Ω. The 5th band would be tolerance.
If you have the remains of original resistor it may be remotely possible to find its value.

Something elsewhere is overloading the resistor causing it to blow. Reason it doesn't blow on bench is because it's open circuit and not hooked to whatever load it hooks to.

Component marked 67 is a diode which can be checked usind a multimeter in diode function.
It may have to be removed to properly check.
 

Baxi

Dec 8, 2021
4
Joined
Dec 8, 2021
Messages
4
Thanks for that,
The Resistor could well be 100 ohm, their is very little remains of the resistor, because when I de soldered it it crumbled up, before de soldering the 4th band looked like black or gold so I replaced it with 10 ohms as gold would be multiplied by 0.1, after replacing it with 10 ohms and trying it in Dishwasher it didn't pop the resistor but the tny264,so may be the resistor is meant to be 100ohm. Would the lower value resistor cause the tny264 to blow?
Thanks again for your patience.
 

Tha fios agaibh

Aug 11, 2014
2,252
Joined
Aug 11, 2014
Messages
2,252
Would the lower value resistor cause the tny264 to blow?.
Yes likely. If you use a lower value it allows more current to flow.
I would look for failed (shorted) component related to this part of the circuit.
Resistor don't just blow up for no reason.

You may try a Google search to see if you can verify 100Ω (or whatever)by finding a picture of this board.
 

Baxi

Dec 8, 2021
4
Joined
Dec 8, 2021
Messages
4
Thanks alot, after doing some more research, found another forum where someone had same issue in identifying the resistor, worked out it was 100ohm. I've ordered that and also TNY267GN (nearest to tny264 I could find).
I'll let you know the outcome, I still need to try and work out what caused the initial failure before i try it again.
Ps the diode seems good.
 
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