toshiba 32bv801b .remote control problem

[petehall347]

have had this tv for quite a while now maybe a year or so . it has had this fault since before i was given it i have decided to try and sort it out as i have another tv to watch in the meantime .
the fault is that the remote doesn't work sometimes but the panel buttons work fine .. it seems it might be temperature dependant but i cant seem to recreate the fault as yet . i wondered if this had been dealt with in the past and where to concentrate on looking .
yes i know its not easy as it is an intermittent fault . this is why i am asking where to concentrate heat and cold to find the bad component .
i have the service manual but it is not like the audio manuals i am generally looking at and understand .
it was only 4 degrees celsius out in my workshop today so that wasnt helping with warming it up .
i think this is correct link to the manual .

[budm]

Re: toshiba 32bv801b .remote control problem

The remote control itself is OK, correct?
Look at CN703 'IR IN' pin 4 on main board with scope to see what you have when the remote is working and when it is not, also verify if the 5V is present and at correct level or not.

[petehall347]

Re: toshiba 32bv801b .remote control problem

p.s when the remote isnt working the standby light doesn't change .like it isnt receiving a signal ..i know it isnt the remote itself as i have tried a different one .

[budm]

Re: toshiba 32bv801b .remote control problem

Look at the signal.

[petehall347]

Re: toshiba 32bv801b .remote control problem

The remote control itself is OK, correct?
Look at CN703 'IR IN' pin 4 on main board with scope to see what you have when the remote is working and when it is not, also verify if the 5V is present and at correct level or not.

will a 40mhz scope do the job ?

[budm]

Re: toshiba 32bv801b .remote control problem

More than enough, it is in 40~50KHz range.

[petehall347]

Re: toshiba 32bv801b .remote control problem

ok will have to wait until it wont switch on with remote ..this may take a long time .. sometimes its fine for weeks . sometimes for a day .
sometimes it wont switch on .other times it wont switch off .

[budm]

Re: toshiba 32bv801b .remote control problem

Well, I would test what I have suggested so you have reference to compare the reading when it is not working.

[petehall347]

Re: toshiba 32bv801b .remote control problem

it soon works again if i remove the mains plug for a while .. have left it in standby for now .

[budm]

Re: toshiba 32bv801b .remote control problem

The reason you do the test now when TV is working so you know what good signal looks like on the scope.

[petehall347]

Re: toshiba 32bv801b .remote control problem

yes i am aware of that ... it might be that i get fed up waiting for it go wrong or i may need to move it . the scope will take some pulling out of the little workshop to take into the big workshop . like i said it might take weeks to go wrong especially with it being freezing out there . the back is off too so that isnt helping . i could do with forcing it to go wrong .i might have to wait until summer if it doesn't play up soon .
i would rather do the testing in the same day if i can .

[vinceroger69]

Re: toshiba 32bv801b .remote control problem

maybe use a hair dryer and heat one board a time untill fault appears

[ReeceyBurger123]

Re: toshiba 32bv801b .remote control problem

Ive actually had cold solder joints on the ir pcb on a Vestel MB62 set which has the Led on as well mainly on the ir sensor have you inspected it ?

[petehall347]

Re: toshiba 32bv801b .remote control problem

Ive actually had cold solder joints on the ir pcb on a Vestel MB62 set which has the Led on as well mainly on the ir sensor have you inspected it ?

i haven't had a close look at it yet .. i tried heating it up with hair fryer and no change .. will remove it tomorrow to have a closer look ..
would this make it so it only turns off sometimes with remote or only turns on sometimes with remote ?
buttons on tv always work .
one thing i noticed in the schematic it has 2 led.s and a sensor for ir . only one led has ever lit up and that one is white .. nothing in the owner manual about it apart from it mentions this ...
Note: The active Standby LED may appear for a few moments when the TV is switched off
...
what is active standby led ?
or is that a bad translation meaning it might not light up for a few seconds ?

[petehall347]

Re: toshiba 32bv801b .remote control problem

making some progress . i heated the power supply up and found when i heat the low voltage caps it craps out on me . as in remote stops working . i froze c828 . then it starting behaving again .heated it up again and same thing ..couldnt freeze it as freeze spray can ran out .. need to save up for a new can . it is very expensive stuff .
i changed c827 and c837 for new ones . it still behaves same ..
have ordered the other caps as i dont have any in stock .
i am not convinced its a cap yet .
ic805 is on the other side of the board right under c828 so might well be the problem ..
yes i know i should have checked voltages but it is so cold out there i didnt want to be hanging around for long .
i did notice the standby light dims to about half brightness when it doesn't switch on with remote so i guess the remote signal is present .

[vinceroger69]

Re: toshiba 32bv801b .remote control problem

for cheap freeze spray use poundland air duster just use the can upside down works good as a freeze spray

[petehall347]

Re: toshiba 32bv801b .remote control problem

for cheap freeze spray use poundland air duster just use the can upside down works good as a freeze spray

i normally get a proper can from maplin .. it goes a long way and works right way up ..

[Andrew F. Ali]

Re: toshiba 32bv801b .remote control problem

The reason you do the test now when TV is working so you know what good signal looks like on the scope.

Look for cold solder joints on Main Bd - CN 703 and on the LED-IR Bd. I would still heat them with the soldering iron Do as budm suggested. I don't think your problem is the intermittent 5V off the Ps Bd.

[petehall347]

Re: toshiba 32bv801b .remote control problem

well repeated tests is saying it is on power board .. i tried heating the ir board first after checking the solder joints . then heated main board ..then power supply .
i know these things can trick you but it seems to be pretty consistent in that area on the power board ..
i need more freezer spray then i can test with board upside down to rule out something on that side of the board .

[vinceroger69]

Re: toshiba 32bv801b .remote control problem

i normally get a proper can from maplin .. it goes a long way and works right way up ..

i also use the maplin stuff as well a little expensive but certainly good spray but in a push the air duster does work if you run out when maplins closed and your halfway through fault finding etc the main thing is you now seem too of narrowed down the area so hopefully you will find the bad part soon.