Mulja tv repair portal
Equipment Repairs => LCD TV forum => Topic started by: Turnip on February 09, 2009,11:51:48
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Hi - I have a Dual DLCD2602 where the standby light glows. Have checked the P/S and noticed that the S/by section alone functions. Reading through back comment, I replaced the two blue 15nf with hope, but that section of the P/S still doesn't start up. Incidentally the 2 x 15nf read OK on value and leakage.
Any ideas - Turnip.
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check a small electrolitic in primery.
check also shotky diode in secondery.
check power on signal in p.s.
good luck
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remove q837 as a check, its in the slow start of the 3525a, if set now starts, replace q837.
let me know
tony walker
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check caps on secondary normally 1000uf ones, can have domed tops to them.
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Thanks a lot - Willyam1, Tony and Visionman. I'm no further on yet after having checked all secondary Shottkys, found no bulging 1000m caps and isolating Q837 the soft start FET. I notice that there should be a 'Power on' signal somewhere - haven't found it yet.
I have managed to get the correct circuit diagram but it's not the simplest I've met - does anyone have any description of function - I have noticed that Vestel (amongst others) don't seem to want to publicise their power supplies, have been through dozens of manuals but not a word.
Again Thanks - Turnip.
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sounds a nasty one , right here goes, pin 6 on pl803 carries the standby/ on signal. what version signal board is fitted, i can post u dump, we use pony prog for our 16 bit nvm.s. feed an external 4 volt supply in on this pin, this may produce 24v, 12v and 33v lines. if so the on instruction is absent.have you scoped drive to the fets, 813/814? remember u are on the unisolated mains (primary)
if you get desperate we can supply new psu.
we have had ic803 fail, and also is the pfc working, normally bridged mains would give you approx 330v dc, but in this chassis it is stepped op to 410 due to the action of the active power factor correction, i have one on the bench now and pfc is active even in standby, please list main signal type, find included hitachi manual, the psu is identical, as i say we can sort your psu if required
regards
tony walker
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Thanks for that info Tony,
I will try repair at some leisure now as customer got bored after two days and bought a new one, giving me the set - sort of win/win situation, either way.
Again thanks - Turnip
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2 days, customers are so impatient, they dont appreciate how hard this job is
regards
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Hi Tony,
When you suggest IC803, might this be Q803 - can't find the other.
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sorry, ic807, its the driver for the fets
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Hi there,
Thanks to all who helped on the problem, especially Tony who gave me clues as to how the power supply should function. For interest - Standby led took several seconds to light from switch on - Standby signal on pin 6 on PL803 was always high, regardless. Other s/by P/S voltages OK. Diode D807(BA159 SMD) (pin 1 of S/by Tx) feeding the bottom end of IC828 on the PFC drive was O/C.
Great fault, hope for simpler things in future - Chris.
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remove q837 as a check, its in the slow start of the 3525a, if set now starts, replace q837.
let me know
tony walker
Sorry to jump in on this thread but I have been reading up on these Vestel PSU's on the boards & decided to go with the info as you posted. I have a 17PW20 V2 here which was trying to come out of standby but quickly returning to standby, The Standby light goes Dim for a couple of seconds but NOT off (It should go off, I have tested the set with a working PSU).
I have so far replaced the 15nF Caps, Most of the secondary Electrolitics & IC809n (As advised else where).
After all this and still having the original fault I decided to remove Q837 as you say, But at switch on the PSU promptly self destructed, The fuse has blown and now I have Q813 & Q814 Short Circuited.
Anyone got any ideas where to go now? I'm really starting to scratch my head at this one now.
Thanks in advance :)
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Hi BUFM,
Guess new PS, or a lifetime of Vestel suffering.
Some of us godly folks do it rather than sitting on a high pole, deep pit, or wearing those awful 'Brian' sandals.
Checking for a few pairs of originals for next year - Chris.
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:33:
Well I'm at this stage with this now.
The shame is that I have three tv's now waiting for vestel PSU's. a 42", a 37" and a 32" and I have two of these PSU's with much the same problem apart from the one that is now self destructed, If I could find out what blew that one up it might give me a pointer on repairing the second one without destoying it. I do of course have the working PSU which I keep for test purposes but I don't really want to use that one.
I was hoping someone might have a list of known faults on these PSU's that I could run through to check on the non working ones.
Thanks anyway,
BUFM.
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Hi BUFM,
Confess little real experience - Tv Tony and Contrast John gave me some good ideas.
Check Vestel 17PS -what-not past-wise - Chris.
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Thanks for the reply turnip, However I am a little confused by it.
I do have to confess my lack of knowledge on these PSU's.
Can I ask what you mean by "Check Vestel 17PS -what-not past-wise"
Thanks.
BUFM...
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Hi BUFM, and sorry,
With this site it's as well to check any past threads that might just be linked to your'e problem - start with Vestel, then go on adding bits 'till threads go cold.
We're not totally perfect - but awful nearly - Chris.