Mulja tv repair portal
Equipment Repairs => PLASMA TV forum => Topic started by: Turnip on February 24, 2018,09:59:26
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Hi folks,
Have one in where Red Led flashes and relay clicks, but it doesn't fire up. Q402/4/5/6 on the Y-Sus board appear S/C. Gather they're IGBTs of some sort, so ordered the Ebay kit.
Wonder if anything else needs to be considered, as unlike Panasonic, the board earths appear good as don't rely on contact with dubious soldered pads - Any thoughts ? - Chris.
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Hi Chris, probably a safe bet it's only the Y-Sus, but the Z-Sus also draws its power from the Y, so a cold check of the Z wouldn't go astray, as well as checking the buffers for shorts. A rather cool looking board, that Y-Sus.
Be keen to see how the kit goes. I almost ordered a kit for a Samsung X-Main this week, but at the 11th hour another punter said I could
wreck his Sammy for parts. Different model but X-Main was identical. Wasn't looking forward to desoldering all those pesky feed-through
rivets. Bruce
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Thanks Bruce,
Kit contained 4 x IGBTs but panel used five. No probs as had a couple not S/C.
Fired up, and the Red Led went out but no backlight. Have a thought that the drive chip might be duff - As with the Panasonic plasma included with the Panasonic kit.
Checked again and those IBGTs still nifty, just not driven. Can't yet find a service Manual to suss driver chips.
Feed through rivets were the UK biz when 'Pye' thought design a signal board using 'em. They went O/C within minutes, and print through became the biz - Chris,
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Hi Chris,
That's a shame. Probably why I tend to stay away from kits which are touted to fix all your tv ailments.
You are aware, of course, there are no backlights in plasmas? Live and learn I guess. Bruce
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Hi Bruce,
You're right as ever. Guess mostly try sort duff Leds and forgot where the light comes from.
Still have the thought that any Y-Sus drive chips might be duff, as Y-Sus appears not driven.
Ebay kit did sort duff IGBTs, so guess the lack of drive issue is rare.
Can't yet find a service manual, though lots of 'User Manuals' where it's 'Refer to the chap who mends tellies but can't get a service manual' - Chris.
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Hi Chris,
Likewise, can't source a manual. These days it's unlikely to have a detailed schematic anyway. Took in a 50" Panasonic today, with a
blown SC board. Think I'll be looking for a replacement board as it seems to have quite a few FETs/diodes gone. Bruce
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Thanks Bruce,
Noticed a repair kit from the USA where it gives more ideas but doesn't say what the chips are so I can try hunt them down. Might have to go for it - Chris.
EAX65331001(2) Repair Kit
• Q401,Q402,Q404,Q405 and Q406
• R425||R418,R423||R419,R424||R417,R422||R426,R420||R427 - above MOSFET gate balance resistors; most likely just a pair will be bad on your board and it may not even be burned open, merely visibly burned, but we still recommend replacing it.
It is important that all balancing resistors for all switching transistors in a group have same value! it does not matter much if it will be 5 Ohms or 7.5 Ohms or 10 Ohms - what matters is that it is the same for all of them (and, to be precise, it must also be high enough to overcome the effect of the internal resistance difference)
We include the balance resistors for all switching transistors because it is possible that your board's batch may have been done with different resistor values than the ones we've seen (it is common for manufacturers to use different values in different batches); so if the resistors on your board are of different value you MUST replace all of them OR you must hack up replacements that add up to the same value as the rest in the group; for your convenience we include all needed resistors for both groups of transistors.
• IC402,IC403 - the driving ICs for the switching transistors; located to the right of the group of transistors, close to the edge of the board; can't confuse orientation because of the not-symmetrical packaging they have.
• Q552 and IC100
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Hi Chris,
Yeah, they're all playing their cards close to their chest. Even by zooming in on the chips, you can't see any writing on them. Giving nothing away - secret sellers business, I guess. Bruce
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Hi Bruce,
Yep, IC402/3 are pretty small, can't make out anything useful.
Mind you, checked the opto-isolator drive chips IC400/1 and they seem to be TLP155E, not that it's so useful as seems they don't go duff - All fun on a day where it's minus ten outside.
Sadly my shed is outside - Chris.
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Hi Bruce,
Got the kit from 'Trump Land' Featuring -
1 x HB541 – 78AG3 – P3Hw (20 pin SMD)
5 x G7S313U – 013P (IGBT)
1 x 2r2 1 watt axial
2 x RJK6026 (IGBT)
10 x 10r SMD
2 x Z02 (Five pin SMD)
Can't yet discover what the chips are, being rather small where the print indicates everything but nothing to me - Chris.
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Hi Folks,
Think mention after replacing bits supplied set didn't fire up, though no measurable shorts. Thought draw a line at 40 Quid and with customer impatient.
Win most, but lose some. Guess if he leaves it, will have another go, but chucking a five foot plasma telly on and off the bench is a bit of a pain.
While ago we used to complain about Toshiba and Sony CRT jobbies, but at least we could get our arms around 'em, and a hundredweight is nothing to a young Telly Basher.
Recall used to carry Philips G500 series up two flights or stairs to the workshop, and without a puff, as in those days most High Street workshops were upstairs. Another branch used to raise sets with ropes, which were nifty 'till the rope broke half way up, as exposed to the elements - Chris.