View Full Version : TV problem
After the huge success of the "lost presets" thread, got to try this.
My big telly keeps cutting out onto stand-by. Usually after 5mins running but is getting worse and now refuses to turn back on at all :mad:
What would cause this ?
I can only think of something overheating and some sort of safety device shutting it down.
Any ideas ?
tim rome
19-05-2003, 20:55
sorry cant help with diagnosis but is it a matsui or saisho by any chance,
tim rome
19-05-2003, 20:59
i had same problem wit a matsui (same as saisho which are both dixons own brand) a few years ago, i took it back and they swapped it over. they didnt tell me what was causing it though
Actual_Ben_Taylor
19-05-2003, 21:01
Similar thing happened with my Sony - apparently due to a dry joint on the main board. Needs resoldering...
model number please? it will start c21 or c25 or c28 or c32 depending on which size it is, and will end in possibly 46, 48, w46 or many other possibles......................
If its bout 4-8 years old, its likely a dry solder joint on the frame ic.
Otherwise, if its bout 4 or less years old it could be many things, but id need to put it into sevice mode to adjust it.
It is 4-8years old and I'll check model number tonight.
We have a repair shop nearby and a dry joint repair won't cost too much.
Its not a 32" widescreen is it?
sounds very much like a temprature related problem, but like ppl have mentioned it could very well be a dry joint on a critical part.
It maynot be standby, Tv's have a protection mode that they will drop into if a fault occours,
I would get it checked out mate.
Originally posted by Dave200
sounds very much like a temprature related problem, but like ppl have mentioned it could very well be a dry joint on a critical part.
It maynot be standby, Tv's have a protection mode that they will drop into if a fault occours,
I would get it checked out mate.
Yeah the protection mode on a hitachi is infact standby.
Model number should tell us much more Jon, and can u tell us if it does anything b4 it shuts down, screen going white, white diagonal lines appearing, screen getting smaller top yo bottom??
Kev
ZXSpectrum
20-05-2003, 14:03
If its an old un and you have accidental household insurance just spill a can of coke in the back... then BANG! happy new TV... ;)
Unless ur policy is replacement to value at which time u find out an 8 yo hitachi is worth bout £60:(
Bet you a tenner the contrast is too high.
My parents Hitachi went into standby all the time until they lowered the contrast a bit. Give it a try :)
Dave
If its a 0-4 yo tv then its cause one of the gunvoltages is set too high cos the shitty goldstar tubes they use cant handle it, as Dave says, reducing the contrast "bodges" it.
They come out of the factory with 100% contrast which is stupid cos it seriosly reduces ur tube life too.
Dave any update on my leds?
**** **** **** **** ****
Sorry Kev :(
I'm a muppet! I'll go get a catalogue this evening on the way home from work (no excuse, they're about 50m away from my workplace)
Dave
no probs mate, just had a mare last night that ud got them and i was supposed to send u dosh and i hadnt, couldnt find a pm with ur addy on it though, so wasnt sure lol
I'll try the contrast thing.
Symptoms:
After 5 minutes running it switches onto standby, normally with the "normal" click but occasionally with a louder "crack" noise which can startle you a bit :)
Switching it back on usually works.
Sometimes (e.g. yesterday) it'll come back on but die again within a few minutes. On a bad day, if you have to restart it loads of times and it keeps dying, a feint green splodge is left in the middle of the screen.
ummm, sounds nice..not..lol
Does sound like it is flashing over, could indicate some type of tube problem ??
OK. The contrast was about three-quarters up the scale so turned it down to about one-quarter. Maybe that'll fix it.
Model number is C28 56TN-311
Jon, unfortunately this is a common prob with hitachi's of that era, and many mods were brung out to sort it.
Id suggest writing a letter to hitachi's british office and requesting that it be fixed FOC as it is a known manufacturing fault, ie not due to wear and tear.
Ive seen this approach work in the past.
Ifr i could remember hoew to put it into service mode id PM u to say how to do it.
Its the "white point" voltage that needs to be reduced, and an earthing spring added to ur lopt transformer and a few regulators need resoldering.
How confident are u with a soldering iron?
Kev
Having turned the contrast down, TV has now behaved very well. Cheers Dave.
Kev, I can connect 30amp car cables beautifully (i.e. blobbily but safely) with solder but would prob be scared taking the back cover off a telly. Cheers for all advice. If problem recurs I shall hassle Hitachi.
Yeah mate the blobily comment tells all.
Dont touch it.
And ur right to be apprehensive bout taking the cover off, just bout and place on a tv circuitry could be sitting with up to 30k volts, whether the tv is on or not.
Kev
Kev,
You work for a TV manufacturer or something aswell ??
The inside of a TV is a VERY scary place indeed. Get someone confident to do it mate!
Dave
Oh yeah, i'll back you up on that dave, although i have to work on the power supply of the tv and thats scary!!
Dave
Dave, nah my trade is TV and VCR repair mate.
remember to short out the 400volt cap b4 u start working on them ;)
oh right :thumbs: mate.
Yeah that cap can give you one hell of a f**king belt..lol
Yip my mate still has a "snake bite" from bout 5 years ago, when he decided to lift the chassis from underneath instead of at the sides.
Kev
owwwwww, although one of the guy here has had a nice scare when he heard a strange noise from the FBT so held the FBT lead and it came out of the FBT:eek: :eek: :eek:
All you could hear was the sound a the EHT going fu**ing ape :D
all fun and games :D
FBT?
errr?
u mean the ht lead from the lopt to the tube?
U dont wanna touch that especially when its on, ur talking up to 30k through that lead, bloody sore!
Yeah that'll be the one mate.. :D:D, sorry thats the lingo used here. haha
Oh yeah i know thats going to hurt if you feel that
Jon there is a problems with the Hitachi
Get a new telly, mine was rented and I had 7 engineers come out and do thngs to it, and they would cure the problem for about a week.
So I got a soney instead.
Not a 32" wide by chance? In black?
wildcard, i see u read the rest of the thread then, its a c28...... ie its a 28inch
not that that matters too much cos it will be the same chassis as the 32, and whether its black or grey or silver is just a differant colour of the same shell.
And as for a sony................................
Im saying nout!
Dave, yeah differant names for things lol
mmmm maybe I should read all of a thread before I post :rolleyes: ;) :wave:
Relaxitscool
22-05-2003, 22:08
Sorry to hijack the thread, but I wonder if I could pick your brains Kev?
I have a 2 year old Grundig 28" widescreen model WF70-3020. Your basic bog std TV. In 4:3 mode the black columns are left down the side of the picture, recently these are concaved instead of straight. Not a massive problem as I can set the aspect to cinema which near enough puts 4:3 in a watchable form on a 16:9 screeen.
However, is this a sign of things to come and should I be looking at getting it sorted asap?
Cheers
Rob
Sopunds like ur EEprom needs reset, either that or u have a fault with ur scan coils (the coils round the tube of the tv).
Its what we would call an East/west fault.
Sometimes they are dead easy to sort, just reseting the EEprom, other times its a night mare.
Best to try and get it sorted now rather than later though.
U could try the old tap test.
A very very technical test where u thump the side of the set.
If the problem cures or gets worse then its a dry solder joint, if nothing changes its probably a reset.
Although lots of things can cause the same type of problem im afraid.
Kev
Relaxitscool
23-05-2003, 11:04
Thanks kev, I'll give it a go.
Rob
Originally posted by Kev
Sopunds like ur EEprom needs reset, either that or u have a fault with ur scan coils (the coils round the tube of the tv).
Its what we would call an East/west fault.
Sometimes they are dead easy to sort, just reseting the EEprom, other times its a night mare.
Best to try and get it sorted now rather than later though.
U could try the old tap test.
A very very technical test where u thump the side of the set.
If the problem cures or gets worse then its a dry solder joint, if nothing changes its probably a reset.
Although lots of things can cause the same type of problem im afraid.
Kev
Can't you re-align the set using a service mode?, that would be easier.
Yeah wat do u think u do in service mode?
reset the EEprom:rolleyes: :D :D
And as i said if it makes no differance slapping the set, then that should work, but if its a dj then ull just get the problem back or oit will go convex instead of concave
mattpayne
23-05-2003, 22:24
oh... mr TV repair man, can you offer me a bit of advise too?? :)
if i peer through the top vent on the back of my telly, i can see the back of the tube, and wrapped around that is one thick grey wire (5mm thick ish) and thats cracked, and you can see the copper underneath... any idea what this wire does??? - the Telly is a 5 yearold Bang & Olufsen MX4000
cheers... :)
from the description id say it was a supply wire to the scan coils.
It must be getting pretty hot to crack its core.
I cant remrember wat b+o is inside, think its a hitachi.
if its not likely to tough another wire then leave it, but if u smell burning or melting then switch it off.
Its possible that the coil pcb has a dj and is arcing onto the wire causing it to heat.
Kev
mattpayne
26-05-2003, 00:01
been like it for a year now... and doesnt get hot... so for the time being i think ill leave it... ill just keep my damp little fingers off it! :)
Took mine to repair shop this week (Hitachi C28 that cut out after 10minutes).
£28 later is all fixed.
He said that some capacitors were never mechanically fixed in the factory, just held in place by glue that deteriorates over time. For some reason this causes them to fail.
A bit vague description but I don't care cos I've got big telly back in time for Christmas :)
sounds like total bulshit.
ill guarantee u he has re-soldered the dry joints.
if he replaced any parts at all ud be looking at over £50
Probably. I'm still happy though.
It would have cost £28 to post it to Hitachi for them to tell me it wasn't their fault.
January 2004
A very similar thread has appeared tonight so don't post any more here.
Just want to say that my telly has behaved perfectly since Christmas. All hail the local repair shop (there are so few left :cry: )
New thread
http://www.sxoc.com/vbb/showthread.php?s=&postid=720502#post720502
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