![]() |
|
|
Thread Tools | Display Modes |
![]() |
#1 |
Badcaps Veteran
Join Date: Oct 2012
City & State: UK
My Country: UK
I'm a: Knowledge Seeker
Posts: 906
|
![]() This operates the drum lamp on a tumble dryer when the door is opened.
The lamp does come on but is strobing at a constant rate. The triac is Z3M and the uc is a MB95F582K. Is it likely the uc is stuck in reset? Resistors, diodes and cap C1 all appear ok. KN1 connections as follows: N.C RST DBG Vcc Gnd Any ideas please. Last edited by notallbad; 10-14-2019 at 06:45 AM.. |
![]() |
![]() |
![]() |
#2 |
Great Sage 齊天大聖
Join Date: Dec 2009
City & State: Europe
My Country: some shithole run by Israeli agents
I'm a: Professional Tech
Posts: 24,066
|
![]() cracked solder joints on atleast one connector there
|
![]() |
![]() |
![]() |
#3 |
Badcaps Veteran
Join Date: Oct 2012
City & State: UK
My Country: UK
I'm a: Knowledge Seeker
Posts: 906
|
![]() Reflowed joints but fault still persists.
|
![]() |
![]() |
![]() |
#4 | |
Badcaps Veteran
Join Date: Jun 2012
City & State: ☻
My Country: Canada
I'm a: Professional Tech
Posts: 6,789
|
![]() Quote:
Last edited by R_J; 10-15-2019 at 01:04 PM.. |
|
![]() |
![]() |
![]() |
#5 |
Badcaps Veteran
Join Date: Dec 2010
City & State: Alberta
My Country: Canada
Posts: 1,938
|
![]() I would also check the large square blue film cap, part of a capacitive dropper for MCU power. Careful it has no discharge resistor, so first use a multimeter to read volts and ensure it has no stray charge.
Resolder connector pins KN3, KN2 and somebody is resoldering but not using enough heat, in the pics. Just need to keep the iron there for a second or two longer. The MCU seems to turn on the triac TR1 for an incandescent 15W lamp. Why does it use an MCU to turn on a light bulb? ![]() I would expect 5V at zener D5 or Z1 as MCU power. |
![]() |
![]() |
![]() |
#6 | |
Badcaps Veteran
Join Date: Oct 2012
City & State: UK
My Country: UK
I'm a: Knowledge Seeker
Posts: 906
|
![]() Quote:
Replaced cap C1. KN1 not connected to anything. KN3 - Lamp KN2 - Door switch 'Live', live and neutral My diagram was wrong - had 'N' and 'L' reversed Last edited by notallbad; 10-16-2019 at 05:07 AM.. |
|
![]() |
![]() |
![]() |
#7 |
Great Sage 齊天大聖
Join Date: Dec 2009
City & State: Europe
My Country: some shithole run by Israeli agents
I'm a: Professional Tech
Posts: 24,066
|
![]() |
![]() |
![]() |
![]() |
#8 |
Badcaps Veteran
Join Date: Oct 2012
City & State: UK
My Country: UK
I'm a: Knowledge Seeker
Posts: 906
|
![]() Across C1 neg and D5 reading 0.9v
and acrosd C1 neg and Z1 reading 2.6v These readings are the same on both boards, I have 2 of them, both faulty with the same symptoms i.e flashing/strobing. Last edited by notallbad; 10-16-2019 at 07:20 AM.. |
![]() |
![]() |
![]() |
#9 |
Badcaps Veteran
Join Date: Jun 2012
City & State: ☻
My Country: Canada
I'm a: Professional Tech
Posts: 6,789
|
![]() Can you read the number on U1 ? you may need to clean the top with alcohol to read the number.
|
![]() |
![]() |
![]() |
#10 |
Badcaps Veteran
Join Date: Feb 2010
City & State: S.F. Bay area
My Country: USA
Line Voltage: 120V 60Hz
I'm a: Knowledge Seeker
Posts: 39,103
|
![]() Both boards are doing the same thing, mmm.
The lamp is just a incandescent lamp? What happen if you bypass the TRIAC? Door switch contacts are good and not intermittent? I wonder if the door switch can handle 15W load since the dryer does not need this stupid smart lamp function so the board can be bypassed. You can bypass the board and use the door switch to light up LED bulb instead too.
__________________
Never stop learning Basic LCD TV and Monitor troubleshooting guides. http://www.badcaps.net/forum/showthr...956#post305956 Voltage Regulator (LDO) testing: http://www.badcaps.net/forum/showthr...999#post300999 Inverter testing using old CFL: http://www.badcaps.net/forum/showthr...er+testing+cfl Tear down pictures : Hit the ">" Show Albums and stories" on the left side http://s807.photobucket.com/user/budm/library/ TV Factory reset codes listing: http://www.badcaps.net/forum/showthread.php?t=24809 Last edited by budm; 10-16-2019 at 10:22 AM.. |
![]() |
![]() |
![]() |
#11 |
Badcaps Veteran
Join Date: Oct 2012
City & State: UK
My Country: UK
I'm a: Knowledge Seeker
Posts: 906
|
![]() |
![]() |
![]() |
![]() |
#12 |
Badcaps Veteran
Join Date: Oct 2012
City & State: UK
My Country: UK
I'm a: Knowledge Seeker
Posts: 906
|
![]() I think the problem lies with never or rarely being maintained, as with all the machines I acquire first port of call is giving them a thorough clean inside and out.
I always recommend that after EVERY use that the water tray is emptied, the fluff filter cleaned, filter housing and door seal and inner door face wiped and EVERY 3 months that the condenser is flushed through with water / wiped over and its housing cleaned. Following these simple guidelines which never really takes long to do can prolong the life of the machine as well as continuing its efficient operation. To be honest the problem here I believe is due to the lamp cover inside the drum cracking and breaking away which then leads to humidity reaching the Smart lamp board which has no other means of protection other than a plastic housing and of course can also damage the main control board which leads to other problems. Last edited by notallbad; 10-16-2019 at 06:47 PM.. |
![]() |
![]() |
![]() |
#13 |
Badcaps Veteran
Join Date: Jun 2012
City & State: ☻
My Country: Canada
I'm a: Professional Tech
Posts: 6,789
|
![]() The ic needs +5 volts on it's VCC pin to operate. There is a small chip cap, C3 check the voltage across it, it goes between pin3 (ground) and pin6 (VCC)
Last edited by R_J; 10-16-2019 at 08:46 PM.. |
![]() |
![]() |
![]() |
#14 |
Badcaps Veteran
Join Date: Oct 2012
City & State: UK
My Country: UK
I'm a: Knowledge Seeker
Posts: 906
|
![]() |
![]() |
![]() |
![]() |
#15 | |
Badcaps Veteran
Join Date: Oct 2012
City & State: UK
My Country: UK
I'm a: Knowledge Seeker
Posts: 906
|
![]() Quote:
Thanks very much. Last edited by notallbad; 10-17-2019 at 05:33 AM.. |
|
![]() |
![]() |
![]() |
#16 |
Badcaps Veteran
Join Date: Oct 2012
City & State: UK
My Country: UK
I'm a: Knowledge Seeker
Posts: 906
|
![]() Well actually, it was a 150nf X2 cap but I only have 100nf but working again.
There is a timer function that switches the lamp off after 2 1/2 minutes or 15 secs after the door is closed, now isn't that 'Smart'! |
![]() |
![]() |
![]() |
#17 |
Badcaps Veteran
Join Date: Feb 2010
City & State: S.F. Bay area
My Country: USA
Line Voltage: 120V 60Hz
I'm a: Knowledge Seeker
Posts: 39,103
|
![]() |
![]() |
![]() |
![]() |
#18 |
Badcaps Veteran
Join Date: Jun 2012
City & State: ☻
My Country: Canada
I'm a: Professional Tech
Posts: 6,789
|
![]() Good to here its working, C4 is used to isolate and couple the a/c to the D1/D2 diodes, C1 is the filter and Z1 should be the regulator for 5 volts that supplies the voltage for the ic, I suspect the voltage across pins 3 & 6 is closer to 5v now.
|
![]() |
![]() |
![]() |
#19 |
Badcaps Veteran
Join Date: Feb 2010
City & State: S.F. Bay area
My Country: USA
Line Voltage: 120V 60Hz
I'm a: Knowledge Seeker
Posts: 39,103
|
![]() It is kind of bad to have the replacement board with bad cap already.
|
![]() |
![]() |
![]() |
#20 |
Badcaps Veteran
Join Date: Dec 2010
City & State: Alberta
My Country: Canada
Posts: 1,938
|
![]() Glad it's working, these appliance boards can be priced crazy high.
Can you post the dryer model number or board p/n for others who might end up here. I see more and more film capacitors failing in capacitive dropper use. It seems to be the metalization is cracking and flaking inside. Epcos parts are not lasting. |
![]() |
![]() |
![]() |
Thread Tools | |
Display Modes | |
|
|