Zenith Z27A11S won't turn on.

this thing is driving me nuts. can't get it to turn on at all any more. anybody have that "turn on" section of the scehmatic they could mail me?

There is probably a cold solder connection, and when the board is sitting in the cabinet, it is being stressed in the fashion to have the cold connection not making contact. Pull the board out, and jig run it. Then you can put pressure on and off the board in various areas to aggravate the fault.

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JANA _____

where is the turn on signal? this is perplexing. it is so close to working i am reluctant to give up and chuck it. Can anybody offer some help or advice? thanks MG

thanks Jana Tried that. i actually just redid all the solder joints in the area and anywhere near the area. tried flexing the board. the thing is that this unit failed while in an entertainement center and never moved..... Probing it hot now... carefully.... i notice that there is no voltage on either side of the power on softswtich. that would make it dificult for it to have any affect i'm thinking. There is a smlal transistor on the hotside of the switching transformer. I'm wondering if that is what must be turned on?. without a schematic i'm just stabbing in the dark. can i hot wire the turn on ckt?

Google the model number. I found this thread . . .

Good luck. Scott

I had a Magnavox that did the same thing. What I did notice is it wasn't when I put the back on, rather once I unplugged it, it would not power back on unless I removed the back, fooled with the chassis and tried it again. Are you having to unplug the set to put the back on? If so, I found a bad resistor in the standby voltage supply. If I happened to touch the circuit (set unplugged), this somehow would reset or drain a transistor that was keeping the set shut down. Replaced the resistor and no more problems. Good luck.

Yes, thats it! I also found a bad resistor in that section near the STR53041 Regulator. it was rx3404 180k. it measured very high. i put in a couple resistors in parallel to make a higher wattage resistor (equiv of ~177k) but it still will not work at all. I was sure that was it when i found that resistor.no joy :( I pulled teh transistor and it seems to be ok. especially since it works intermittently. now is a new problem. the top of the board is screened with the opposite BCE pin configurations as the bottom of the board. Now i'm not sure which way the transistor goes back in :/ I'm VERY close now. Thanks for the reply Golf. right on the money. i actually found a ref pasted below that helped me track down the resistor it is originally for a different TV but obviously uses the same chassis.

#################################### Using STR53041 Regulator Always replace: CX3413 = 22mf 63V, CX3416 =

100mf, 25V, RX3404 180k (use 1/2W). Also check: RX3407 = 47 ohm,1W, Rx3408 22 ohm, 1/2W QX3401 121-1348 (use ECG184 or one of many other transistors with similar spec's listed in the ECG guide under TO-220 and TO-220J case styles 4 only (A 1Amp rating is required). If that doesn't do it replace ICX3431 - STR53041. ####################################

I'll keep plugging away but anymore help will be greatly appreciated. thanks MG

yeah that was me....same set. it got shoved asside till i descided to clean up and tackled it again. nothing in that thread took me any further.

If the transistor is an NPN, the emitter junction should go to ground (looking at top of board). If PNP, the Collector should go to ground. You should be able to determine the transistor type using a DMM. Good luck again.