TH-P50ST30A - 7 blinks-SOS7

[tw2005]

No pics actual TV sorry. Photos for guide and our St30 appears to be more like GT30 for boards in the US

7 Blinks, Shorted SC2, SU/SD boards ok(thank god)

Had the usual loose screws and arc marks on both Sc & SS. replaced thoses and re tightened all others

On SC board, in cct , 3 x RJP30H2, 3 x 30F131, RF1501, DAF30A all shorted

After isolating each, 3 x RJP30H2, 1 x 30F131.

Replaced both banks of 3 (6 in total) with FGDP4536 which are working well in the 50U30A.

Powered it up, 8 blinks. pretty confident SC was good. Did a quick check of the SMD transistors and diodes, found RCJ330N25 FET short. had nothing exact or SMD so had a STK1820 which is under rated in comparison and TO220, no heatsink.

powered up and now working, that FET does not even get warm.

The TV had over 10 000 hrs up.

[djw43]

Re: TH-P50ST30A - 7 blinks-SOS7


nice work!

[tom66]

Re: TH-P50ST30A - 7 blinks-SOS7

Nice fix. Good TVs. Were screws dodgy?

[tw2005]

Re: TH-P50ST30A - 7 blinks-SOS7

Nice fix. Good TVs. Were screws dodgy?

some loose, not as many as the U30, On the soldered lands they are no good but on the metal pads they were still tight

Every screw on the rear panel though has been spun. Wrong sized phillips used I'd say.

[tw2005]

Re: TH-P50ST30A - 7 blinks-SOS7

Picked up another ST30 today. Advertised as 7 blinks.

SC2 was shorted, praying the buffers were ok.

Had a spare SC ready to go, did a quick check of the outputs to Vfg, no shorts, Vfo read ok.

Fired it up, top half had maldischarge, no errors but I shut it down pronto.

Did full resistance test, on the SU. Vfo ok, Vscn-f ok, VF5V , high resistance in meg ohms normally I see 30K there.


Had a spare SU destined for a U30 but the ST is getting it instead.

All fixed.

the usual loose screws about 4 on the SC , 2 on the SS.

Original SC with SC2 short, usual 3 x 30F131 + 3 x RJP30H2, installed and that's working again too, back to having my spare.

I do think the picture on these is better than the 2010 series.

Edit: see below, that Su is working fine in the U30

[martino]

Re: TH-P50ST30A - 7 blinks-SOS7

Did you sub the 30F131 with FGDP4536 or was that the RJP30H2. (too lazy to pull specs up and prob answer that myself,lol. running in the need of a lot of 30F131's lately and I never seem to have enough of em)

[tw2005]

Re: TH-P50ST30A - 7 blinks-SOS7

Did you sub the 30F131 with FGDP4536 or was that the RJP30H2. (too lazy to pull specs up and prob answer that myself,lol. running in the need of a lot of 30F131's lately and I never seem to have enough of em)

I did a bulk purchase of the exact parts from UT so it's as listed.

happy to report nil issues with those Fairchilds in the U30 I did 18 months ago or the other ST30.

I do have to make a correction about the SU resistance, weird thing, I saw 30K for a blink then it was high ohms again.

Anyway I have another Su with an IC removed and I noticed it had high ohms on the VF5v and it works up to the missing chip.

So I just put this Su and for whatever reason it's working in the U30.

Confused, unless there was a bad connection or something but I'm happy.

So I'm just about to edit the previous post.

[Alastair E]

Re: TH-P50ST30A - 7 blinks-SOS7

This week I've been potching with a 50U30. A 7 blinker, turned out to be 2 buffer-chips on the upper (SU?), the SC and SS were OK.

The chips came in this Wednesday, so changed 'em,--Which was fun, and found some decent screws with flat and spring-washers for the SC/SS boards.

Also added heatsinks to the majority of the SC parts and to the buffers which didn't have any at all. Stuck 'em on with silicone heatsink-plaster...Now, Where's me box of fans......
Prolly add some heatsinking to the SS as that gets pretty damned hot too

--Even though the budget version, it does have a great picture at 10,000 hours, and has DTV-HD--this set may just upgrade my 50G10...

[tw2005]

Re: TH-P50ST30A - 7 blinks-SOS7

This week I've been potching with a 50U30. A 7 blinker, turned out to be 2 buffer-chips on the upper (SU?), the SC and SS were OK.

The chips came in this Wednesday, so changed 'em,--Which was fun, and found some decent screws with flat and spring-washers for the SC/SS boards.

Also added heatsinks to the majority of the SC parts and to the buffers which didn't have any at all. Stuck 'em on with silicone heatsink-plaster...Now, Where's me box of fans......
Prolly add some heatsinking to the SS as that gets pretty damned hot too

--Even though the budget version, it does have a great picture at 10,000 hours, and has DTV-HD--this set may just upgrade my 50G10...

same, I've got 2 of these both SU fail.

1 ic on one ( 3rd down from top) and 2 on the other( 2nd & 3rd). I've decided to have a go myself.

What do you use to cover the pins with?

i had some info sent to me and this is what panasonic suggests.

SE 9189 L Gray RTV
(Dow Corning, http://www.dowcorning.com)

[Alastair E]

Re: TH-P50ST30A - 7 blinks-SOS7

I used some Ulti-Meg HV varnish--the stuff that another member here--Hates! Good stuff though...

TBH--I doubt there would really Be an issue if you left 'em bare. While raiding old buffers for heatsinks, I noticed that LG only use silicone to stick the sink to the buffer-chips. The rows of pins Under the sink don't have any silicone on 'em at all, they are also open to the air at the sides under the sink between the chips, the silicone isn't continued along the full length of the sink (One sink--two chips like Pan do....)

So much for the possibility of moisture getting in and upsetting things--as the other member, That I had a 'debate' about this very thing, suggested...

BTW-- It was the top and next one down in my SU board...

[martino]

Re: TH-P50ST30A - 7 blinks-SOS7

I think it's time to share the secrets of how to remove the silicone type stuff off the buffer Ic

[tw2005]

Re: TH-P50ST30A - 7 blinks-SOS7

I think it's time to share the secrets of how to remove the silicone type stuff off the buffer Ic

I think it has been discussed in other threads. Don't know of any sure fire way but I think flocko found some silicone dissolving product and I find using acetone whilst it does not dissolve it does seem to alter its properties to help crumble it away.

I use wooden toothpicks and those bread packet clips to scrape it away, slow tedious job if you want to keep the board intact.

[tw2005]

Re: TH-P50ST30A - 7 blinks-SOS7

Thought I'd add this little scenario. Still experimenting with the fake 30F131 devices, found some with different markings and hoping they were maybe functional tried them and failed. Loud pop and flash of light.

So I used known good parts and put the board in which checked ok and no go, 7 blink.

Assumed I missed something I put in a known working board, no go 7 blinks.

Starting to stress, I think I've blown the buffers, no they're ok.(thankfully)

Disconnect Sc20, goes 8 blinks normal, notice LED lights on SS, not on SC and SC is good.

Check Vsus, normal for SS P11 , nothing for SC P2. Remembering the flash of light , i was a reflection and more centre of TV, I had a quick glance at the P board and checked fuses, ok.

So something is blown on the P, remove it and the cct board trace to P2, lacquer burnt off and trace fused.

too many failed SC boards probably stressing the trace and this time it vaporised.

Makes sense, disconnect sc2 and you get 7 blink, so same , same.

Just something else to consider when you get stuck.

[Moreno83]

Re: TH-P50ST30A - 7 blinks-SOS7

Good to know but that takes a lot of failed SC boards to get to this point? You also had a blown IGBT under the heatsink or just the trace going bad?

[Moreno83]

Re: TH-P50ST30A - 7 blinks-SOS7

My 50GT30 just shut down again , now Q423 , Q422 , Q421 and all igbts/diodes near buffer are all shorted.

Q401/402/403 are still ok.

I first got a burning smell and turned tv off. Turned it back on and the bang came.

Back to square one

[syaoran123]

Re: TH-P50ST30A - 7 blinks-SOS7

I found out that using parts/repair kits from ebay or shopjimmy have always worked but only temporarily for my first 3 repairs. When I started using original parts, it had never skipped a heartbeat. Lucky I didnt have to buy them. I had a SN board with faulty buffers and spare SS which had a bunch of salvageable parts on it. Also the Y-sus or Z-sus from a samsung 50Q91HD has a multitude of RJH3047 which can be used as a substitute for both the RJP's and 30F's

[Moreno83]

Re: TH-P50ST30A - 7 blinks-SOS7

Good to know! Where did you order the original parts? Everybody on ebay can say that they are original panasonic parts haha

[Moreno83]

Re: TH-P50ST30A - 7 blinks-SOS7

Btw the "RJH3047" on ebay got longer legs. You cut them off so they fit on the board or?

[syaoran123]

Re: TH-P50ST30A - 7 blinks-SOS7

Like I said, I didnt have to buy them. I desoldered the parts off other boards. That's how you can be sure they are original.

The RJH3047 are a discontinued product so you won't be able to order them in. But if you have them from eg. an old samsung y-sus board lying around, then chances are they will be in a much larger package. It will fit the board still if you bend the legs while being careful where you mount them on the board.

[syaoran123]

Re: TH-P50ST30A - 7 blinks-SOS7

The first picture shows the job I did on a SN board by transplanting an RJP3047 from a spare LG Y-sus (forgot which model number).

Second picture shows the goodies you will find on a spare SS board that may be useful on a SC or SN board.