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Equipment Repairs => PLASMA TV forum => Topic started by: Turnip on September 11, 2014,11:11:22

Title: Panasonic TH42PZ70B - 7 flash problem
Post by: Turnip on September 11, 2014,11:11:22
Hi folks,

Hate old heavy plasma but. This one works quite normally initially for 15 minutes then cuts to S/by with the 7 Red flash. Switching on again works for a shorter period so suspect something heat related. All 4 fans are working a treat.

Chap on 'Bad Caps' suggested a 2N3995 somewhere in the set but thought to check folks who might just know B4 I go hunting - Thanks - Chris.
Title: Re: Panasonic TH42PZ70B - 7 flash problem
Post by: downunder on September 12, 2014,04:18:41

Hi Chris,

Technical explanation of code 7 = Driver SOS2 (SC Floating Voltage Area) and is attributable to SC (Y-SUS),
SU (Upper Buffer) or SD (Lower Buffer).

If SC is operating, there should be a green LED illuminated on it. Disconnect SU and SD from SC one at a time and turn the set on. If it operates, SU or SD faulty, and upper or lower half of screen may light up.

If one buffer is gone, Panasonic recommend replacing both, but the panel may be faulty. If the TV still presents with code 7 with SU and SD disconnected, then the SC board is cactus.

I don't attempt repairs to these boards. Flea may be way to go. Bon chance. - Bruce
Title: Re: Panasonic TH42PZ70B - 7 flash problem
Post by: Turnip on September 12, 2014,10:52:04
Hi Bruce, and thanks,

Seems Y-Sus and drive boards are a problem with plasma. Was a little confused as usually such problems occur at switch on, not after 15 minutes of perfect picture. Green LED glows on the board, and no drive chips appear 'cactus' as often the case.

For amusement checked out the Flea, where both upper and lower drive panels are available at £25 a hit, and working sets £50.00 if prepared to travel a bit.

Suspect won't bother try mend, as panel might well be duff, and Norfolk folks don't care to pay for failure.

Upside - Had a couple of nice cheapy LCD earners in today, where mains rocker switches were O/C.

Who wants/needs plasma - Chris.
Title: Re: Panasonic TH42PZ70B - 7 flash problem
Post by: downunder on September 13, 2014,03:54:09

Hi Chris,

Suspect the Turnip does not like plasmas. They're just another TV, says Bruce philosophically, and bear in mind that failure is hereditary.

In hindsight, the fact that it works fine for a short time could make diagnosis a nightmare. Code 7 can also be caused by a duff panel.

That does it, I hear you say. Are Norfolk folk really such tight wads?

I've taken my "philosophical" pills today. - Bruce
Title: Re: Panasonic TH42PZ70B - 7 flash problem
Post by: Turnip on September 14, 2014,10:33:45
Hi 'Philosophical' Bruce,

Not so sure what you mean by 'Failure is hereditary' - Natch not taken personally, as you prob haven't met me mum/dad who expired way back.

Father was trying construct a 'Viewmaster' in the loft from genuine 'Blue Prints' and those Red Sylvania metal sheathed EF50s left over from the war, when the Yanks went home.

Mother was a reader of books 'till I brought home a Pye V14C from my first employment in the '50s.

She quickly gave up reading, as the V14C had a continuing line hold problem, and she couldn't both turn the page, and twiddle the Line Hold knob at the same time. She eventually expired after many years of conversations with 'Terry Wogan' - Happily.

Admit as a callow youth, threw out Pye's wonderful flywheel whatsit stuff, and fitted triggered synch circuit pinched from a Decca DM4C of the time. Most customers were happy as didn't need replace the PCF82 every two months. Some however complained of interlace problems, as I couldn't quite get the alternate field scan to start at the appropriate time.

Suspect such customers have moved on, as not a word for some few years.

Talking 'Tight Wads' - While ago, there was a Telly basher in every Norfolk/Suffolk village. They were either robbers or bought spares from a certain UK firm.

Knew a chap, who when mending VCR, used to buy new screws for every one removed to do repair - He was an ex 'PYE' tv man, though too young to have devised the  'Flywheel Synch'.

Eventually, all robbers and strange folks either retired, or got Government jobs, where cost isn't an issue, even today.

Myself - Got close to the Council local tip, where stuff might be got free, if mend their horrible plasma.

Tip folks always go for plasma, as size is most everything to Intellectuals.

Upshot - Of course all other local menders totally expired, so seems I'm the only one left, but have good chum from the 60s who likes folks, and can explain to customers why I can't mend their thing - and they love him for it.

Never had the knack me'self, not being particularly sociable to folks who assume I'm out to screw them.

Mention, as a social aspect is surely a good thing, otherwise, telly mending might drive one nuts -  Chris

PS - Another old mending chum called yesterday, and suggested Plasma is now 'Cactus' - Hadn't noticed, but he's a chap who doesn't now mend but reads the runes - Don't me'self, too busy still trying mend the crap.