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RCA 27F520T, M134C always cycling on/off    
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PostPosted: Mon Nov 10, 2008 12:31 pm    Post subject: RCA 27F520T, M134C always cycling on/off Reply with quote

RCA 27F520T , chassis M134C , always cycling on-off till you unplug it.
I've check all the tact switches , all are good (no leak and 0 ohms when pressing).
I decide to unsolder the IR sensor , same results.
I remove the power tact switch to be sure , same thing.
Tried to bend the power/main board , still same.
Checked all soldering , nothing bad found.

Anyone experienced this trouble in RCAs?

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PostPosted: Mon Nov 10, 2008 12:32 pm    Post subject: Reply with quote

I would have to look at the print but I believe those switches are configured
in a matrix configuration. One of the others may have enough leakage (I know
you checked), to simulate the power on/off condition.

Perhaps try removing all of them and operate off the remote to be sure.

PostPosted: Mon Nov 10, 2008 12:34 pm    Post subject: Reply with quote

Gaetan, Had three come in with the same problem. I ordered the control board
P/n 270961 ( which is no longer avail.) And that fixed the problem. It was cheaper to order the whole board than to replace each tack switch.
So know when I get one in like that I replace all the tack switches p/n 267136, I use 215500 from Bursma Elec. Or Acme with no problem. I also want to caution you about the IR reciever on that board P/n 270382, It can cause weird problems such as what your having.

Thompson also also says that R036a (10K) and C 027 p/n 267136 can cause this
but not the case for me on this kind of problem.
You can float pin 4 at the connector of P001B, that will disconnect all the tack switches but allow the use of remote.

You can just pull out the connector when you get it fired up and see if it behaves, is so, look into the Tack and Ir receiver.
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