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Sylvania LC370SL8 - no power, green LED flashes    
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scoop113



Joined: 30 Mar 2015
Posts: 5
Location: Florida

PostPosted: Mon Mar 30, 2015 1:53 pm    Post subject: Sylvania LC370SL8 - no power, green LED flashes Reply with quote

Sylvania 37" HDTV
Model LC370SL8

Set won't power on. Red standby LED is lit. Upon pressing the power button, the green power LED flashes slowly about 75 times, then the flashing speeds up for a few seconds, then it goes back to the solid red standby LED.

There is no sign of life on the screen. Previously, upon pressing power, the TV would make a loud BRAAAAP sound. For lack of a better description, it sounded like a loud fart. Now it is not doing that anymore.

The first couple of times the TV acted up, I was able to disconnect the power for a while and it would return to normal. That no longer works.

Any help is greatly appreciated.
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JTS1957



Joined: 21 Jan 2009
Posts: 2247
Location: Far, Far Away

PostPosted: Mon Mar 30, 2015 4:38 pm    Post subject: Reply with quote

Have you read through this? Especially the last couple pages.
http://www.riddledtv.com/forums/sylvania-lc370sl8-wont-turn-on-t1264.html
scoop113



Joined: 30 Mar 2015
Posts: 5
Location: Florida

PostPosted: Tue Mar 31, 2015 12:23 pm    Post subject: Reply with quote

I did. But since he had no power LEDs or other signs of life, I did not know whether those troubleshooting steps would apply to my case.
JTS1957



Joined: 21 Jan 2009
Posts: 2247
Location: Far, Far Away

PostPosted: Tue Mar 31, 2015 1:07 pm    Post subject: Reply with quote

I presume NO DVD?

Check all diodes on secondary of T601. If none are shorted, check for DC voltage on the cathode of each reference to ground.
scoop113



Joined: 30 Mar 2015
Posts: 5
Location: Florida

PostPosted: Tue Mar 31, 2015 2:40 pm    Post subject: Reply with quote

I'm afraid you're going to have to hold my hand a bit. I assume that the secondary windings of T601 are on the side with 8 leads, which would be on the top side. Here are the readings for those diodes (and any others nearby):

D1607 - .148
D1601 - .147
D647 - .127
D640 - .127
D641 - .157
D637 - .155
D632 - .186
D655 - .503

All show infinite resistance with leads reversed.

When you say check for DC voltage on the cathode with reference to ground, do you mean chassis ground? Should the board be completely connected to the set, or just the power leads?
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JTS1957



Joined: 21 Jan 2009
Posts: 2247
Location: Far, Far Away

PostPosted: Tue Mar 31, 2015 2:59 pm    Post subject: Reply with quote

Pins 11/12 of transformer T601 is the correct Cold ground reference. (Pin 7 is Hot ground reference). Primary of T601 is Hot / Secondary is Cold.

Everything connected normally.
Readings with set plugged into outlet (power button NOT pressed ... aka set OFF - In Standby), then readings again once power button has been pressed and released ... aka set ON.
scoop113



Joined: 30 Mar 2015
Posts: 5
Location: Florida

PostPosted: Tue Mar 31, 2015 3:16 pm    Post subject: Reply with quote

Sorry for my ignorance, but the pins on the transformer are not numbered.
scoop113



Joined: 30 Mar 2015
Posts: 5
Location: Florida

PostPosted: Tue Mar 31, 2015 9:05 pm    Post subject: Reply with quote

Reseating the cables seems to have sorted it -- for the moment anyway. Thank you very much for your time and effort. Smile
jotvguy



Joined: 03 Dec 2015
Posts: 2
Location: Maine

PostPosted: Thu Dec 03, 2015 4:09 am    Post subject: IT'S A CAPACITOR ISSUE Reply with quote

Scoop113, I repaired one of these yesterday, if slow to start or blinking green led, I found 5 capacitors that were not within +- 20% tolerance on the set I was repairing, all but 1 located on the sub power supply module in the middle of the TV.>> 1- 1000uF 25V and 1000uF 10V. 2- 10uF 50V all located near the transistor heat sync in the center of the pc board. The last part was once again a 10uF 50v located on the right side of the heat syncs on the main power supply module. I have not given location item #'s as I've already sent the TV home to my customer.
If you still have this TV I hope this helps.
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