Mulja tv repair portal
Equipment Repairs => CRT TV forum => Topic started by: joe-joe on March 18, 2009,17:49:11
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Hi everyone,
I hope some kind sole out there can help me with this problem...
My 5 year old Toshiba 32ZT29B has developed a fault that happens when the TV is first switched on.
When first switched on there is sound but no picture at all, the screen just remains black. After switching on & off a few times the screen comes on, sometimes all Purple or Green, this can last for approx 30 seconds or a few minutes before the picture come on. When the picture comes on all is well & the TV then performs normally, except for the occasional freeview split second dropout (built in freeview tuner) where the screen flashes up a mosaic...this didn't used to happen before this fault started.
Could anyone give me any pointers as to what this fault is likely to be?
I know the TV is 5 years old & as CRT has been replaced by flashy Plasma & LCD screens TV’s like this are virtually worthless, but it seems such a shame to throw this TV out if a repair won’t cost a lot?
Any help greatly appreciated.
Thank you.
(http://i130.photobucket.com/albums/p256/on1wheel_2006/32ZT29Bpurple.jpg)
(http://i130.photobucket.com/albums/p256/on1wheel_2006/32ZT29Bgreen.jpg)
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Hi Joe-joe,
It sounds like you have got a faulty Freeview module
Hope this is of some help
Brian
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Thank you for your reply Brian.
The TV also displays the same fault if I try to view sky via AV connection, would this happen if it was the freeview module?
When the TV was switched on tonight the picture came straight on however the pictures had a very bad motion lag to them...if someone moved you could see the motion trails behind them....then all of a sudden the TV switched of all on its own.
I switched it straight back on...on came the sound but the screen stayed black...then the screen flickered with Purple & Green before the picture returned & the time the motion lag was gone & the picture normal.
Thank you.
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Hi
Does this set have a dfs module as you mentioned mosaics?
If so just give it a gentle tap when faulty to show up fault.
But first impressions were CRT fault.
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Hi,
Yes I believe the TV does have a dfs module....:unsure:
When switched on from cold the TV now takes approx 10 minutes before the picture comes on...until it does the screen just stays black but the sound is there...then it sometimes flicks up a green screen then purple or a mosic before the picture comes on.
I tried the TV this morning...usual black screen no picture. So I removed the back so I could tap things to see it had any effect...however when switched back on with the back removed the picture came straight on....obviously removing the back of the TV must have disturbed something to make the picture come on....I'm now thinking along the lines of a bad solder joint somewhere.
Cheers.
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Hi joe-joe
Symptoms are those of a faulty dfs module, a common fault on these and similar models. Could be a type MDSF02A or MDSF03A (usually marked on the module). Tapping the module should instigate or temporarily cure the problem. Although it is a case of intermittent contacts inside the unit, replacement is the only solution. Spares are available from Charles Hyde
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Hi John,
I have located the DFS module in the TV it's the MDFS02A version....I have tried tapping it but it's not making the fault show up.
At the moment the back is still off the TV & the problem hasn't shown up since the back was removed.
I know from trawling the Internet that a lot of the ZP range of Tosh TV's suffered from DFS module faults....apparently Toshiba are aware of this and are supplying new modules free of charge, once the fault is diagnosed by an engineer. (Even if the TV is out of warranty)
The new module is normally sent to the engineer to fit. I believe the ZP uses the MDFS03 module though.
I'm not sure if Toshiba recognise the module in my TV as being a problem but the symptoms do sound quite similar to some of those displayed by the ZP range.
Think I'll give Toshiba a ring to see if I can establish if my module would be a free replacement if it was found to be faulty.
Cheers.
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Hi Joe-joe,
The DFS modules are un-reliable but you can normally tap them to trigger the fault.
The freeview module can exhibit symptoms in analogue and freeview, but if you can get
a free DFS module free of charge then perhaps try that first.
Regards
Brian
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Hi,
Bit of an update....
I had another tapping sesion today & when tapping the DFS module there was some interference but just small flickers across the screen...I gave it a couple of good taps & the screen went Green / Purple / mosaic but then back on again. I figured I would get a better result with the screening panels removed from the module as I could then directly tap the circuit board inside.
Sure enough as soon as I tap the board the picture flicks off & looks like below.
I would say that this is pretty conclusive that the DFS module is the problem…what do you think?
Cheers.
(http://i130.photobucket.com/albums/p256/on1wheel_2006/Photo-0160.jpg)
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Hi joe-joe
Seems fairly conclusive, but the only slight worry would be that tapping the module caused a problem in it, whilst the original problem lay elsewhere. - Unlikely but possible. To make any progress with fault finding the module needs to be replaced with a known good one. Unfortunately the cost is rather prohibitive so its worth trying Toshiba as you suggested.
Good Luck
John
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Hi,
Yeah I see what you mean John but the fault I get when I tap / touch the circuit board inside the DFS casing is the same sort of screen fault that I was getting before I started the tapping.
I realise the pictures I have posted in my posts show the fault to be different but the fault does take on various forms & the pictures I have posted are just how it has been at that moment in time...if you follow what I mean.
From what I have read, & from the pictures I have seen on the web a failing DFS module can show up in lots of different ways.
The pictures below are what people have experienced due to a failing DFS module on the ZP range of TV's...I have seem the same sort of images on my screen.
(http://www.avforums.com/forums/attachments/crt-televisions/51213d1174684069-toshiba-36zp38-)
(http://www.avforums.com/forums/attachments/crt-televisions/69864d1200153247-toshiba-36zp38-problem-cimg2017.jpg)
(http://www.avforums.com/forums/attachments/crt-televisions/53850d1178188500-toshiba-36zp38-problem-img_0582.jpg)
I'll give Toshiba a ring tomorrow if I get a chance & see what I can come up with.
I'll let you know how it goes.
Cheers.
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Hi,
Well I contacted Toshiba this morning & they really were very helpful, however they say that my TV (32ZT29B) did not have widespread problems with the DFS module so they do not supply them free of charge for my model.
I still believe it is the DFS module that is causing the problem but given the price of a replacement I'm not prepared to replace it just in case there is another fault somewhere.
Even calling in a TV engineer out to look at the TV is going to probably cost a lot more than the TV is worth & I think it would be probably wiser to put the money towards a new TV.
Thanks to everyone who offered advice on this thread.
Cheers.
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Hi
send the module to sers in sale.they'll reflow the ic's and send it back for about 40 quid.should be cheaper than a new module.check www.sers.me.uk but i have to qualify this with i've never had to use their service so this is not a recommendation but you might feel they're worth a try.They supply and fit philips painter ic's as well which could still be useful to many
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ex ttg,
Thanks for that...I'll bear that in mind.
Cheers.
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if these sets use auto grey scale tracking this can be upset by a slightly low emission crt
tony walker
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I was using once this company www.sers.me.uk and ok very quick service
and tv never come back.
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Hi,
Just thought I would let you all know that I have fixed my TV :clap:
A new module was out of the question due to price, I did consider having the module re flowed by www.sers.me.uk but as I wasn’t 100% sure that the module was the sole cause of the fault I didn’t wasn’t to risk having this done as the money would be wiser spent put towards a new TV.
So considering all of the above & the fact the TV is probably only worth about £63p these days I decided to remove the module myself & have a go at re flowing it…if it didn’t work the TV was going in the bin...a "Destructive fix" as I like to call it (It will either end up fixed or f***ed) :biggrin2:
So I fired up the soldering iron & got the DFS module out of the TV. Once on the bench I used a bench magnifier to see if I couldn't’t see any obvious dry joints in the module, however the legs of the IC’s are very small so a bad joint would be hard to spot unless you had better magnification which I didn’t, so I set about re soldering all of the legs on the IC's….30 minutes & a few choice swear words later I had somehow managed it.
I re fitted the module to the TV….Happy days. :clap:
The TV has been fine since I re soldered the module on Thursday so I’ll just keep my fingers crossed it keeps working.
Thanks to everyone who offered advice with this problem. :brinda:
Cheers.