thunder storm yesterday, nearby lighting strike, and now one of my BPC's shows no sign of life. hoping for something simple like a fuse, as I have no clue how to work on these POS's. My vintage stuff just laughs it off.

the CRT is in good shape I wonder if I end up scraping this thing of there is any reason to save the CRT, like in 20 yrs from now will these be sought after. due to the cheapness of them I dont think anyone saves them. Unlike older vintage stuff that actually cost a lot (and there for the folks that actually paid for them did not junk, not until the kids or grand kids got them did the vintage stuff get tossed). Of course with all the NLA parts perhaps even the CRT's will be useles since a chassis could not be repaired.

They make DANDY targets...just sayin'...(grin)

On a lot of the newer BPC sets, I find that lightning will take out the fuse and one (or more) of the bridge rectifier diodes. Sometimes, the voltage regulator IC or switching transistor will be shorted and there will sometimes be a burnt trace or two in the power supply. If it turns out to be anything deeper, I'd junk the TV.

I've seen lightning strike a TV and only do minor damgae and I've seen it strike a TV and literally turn the PC board chassis to toast. And, I have done extensive repair to lightning damaged TV's; but, that was back when a BPC TV was still worth the effort. Now, I wouldn't go past the power supply.

board

a few more pics

I know it makes little sense to fix this thing, esp with others in line to be fixed, but I guess I am just wondering how you go about trouble shooting something this late? is it a check here then look for this kind of approach? I can barele follow the traces as they are so small.

The relay is not energising. the transformer has 10vac on the secondary from there I get lost quick. I found a single diode that had 10vac on one side of it (compared to other side of the secondary), but on the other side of the diode I get 8vdc? seems odd.

Panasonic CT-27GW1

That is switching mode power supply run, I wonder if the relay is for degaussing only. The molded grey transformer is the standby supply. hmmmmm

If you do junk it, be sure to salvage the higher voltage rated capacitors and power resistors. And some of the coils, and relays.Some can be used in vintage tube TV sets.

I've been wondering for a while now, is it possible to adapt an inline CRT from a BPC set to a vintage TV? Reason being older delta gun CRT's are getting scarce and nobodys rebuilding them anymore. Perfectly good BPC inline tube sets are being tossed out every day so why not try to use them?

Sorry for the sidetrack!

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I was thinking about doing just that (jumping the relay). will give it a try.

I would fix it, its always worth it to learn something new! And you can take this to the bank, someday someone will be saving those sets too. I remember everyone thinking '74 mustangs were junk, and ugly, back in the 90's now they are being restored just like the older ones. All you guys turning your nose up at black plastic crafted tv's should be embracing the last in the generation of crt sets. I have been carefully picking and choosing the free and $10. 20" - 27" BPC sets on CL and just sticking them in the shed. And I use them for our living room set, main watchers. Just like when I was a kid and people were tossing round screen sets and no one thought about it, history repeats. history repeats.

I pretty much stopped sharing schematics because no one ever says thank you or anything. Must be that entitlement virus going around. But hey, this is DAVEWM... so, here you go, this should get you going.
Have fun with the surface mount world.
http://justsmog.com/Clay/davebpc.gif

Thanks, I never could find a 12v anywhere in the standby, this should help me.

if I break the circuit at L001 the 12v source and the 5.2v at 4a come up, reconnect L001 and the stand by 12v drops to 7v, the 100 ohm resistor R005 gets hot. So it looks like a problem after L001. I checked the to eletrolytic caps, both fine. the .1 looks like some kind of surface mount, my guess is that is not the problme. The 4b goes directly to the main mother board IC, so I am thinking something bad happened there. Dumb thing must have 80pins on each side, but it is thru holes so I guess if I got real board I could attempt to remove, that is assuming its the problem AND I could find a replacement. D011 was also shorted. I replaced it with some generic diode. before doing that the 12v was 5v (replacing it brought it up to 7v, disconnecting 4b brought the 12v source back to 12v).

wow, I found one for 14$, now I will have to think about fixing it.

two pins 22 and 61 are the only ones that get the 5.2v that if I disconnect both the standy PS voltage pops back up to where it should be.

I am tempted to leave them disconnected (so the 5.2v is not shorted out), plug it back into the yoke and CRT and jump the main power relay just to see what happens.

Or go ahead and pop for the IC and do it right... worst case I am out 15$ and some shipping.

both those pins read about 4 ohms to ground, which considering they are fed 5.2v puts each on of them pulling over 1 amp. I can't see how that would be correct. just checks, SAM show 34ma in at the output of the standby power supply.

Here it is
http://html.alldatasheet.com/html-pdf/126472/ETC1/MN1874085/202/2/MN1874085.html

hmmm eprom. I hope all the info I need is in the sams.

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Yep, the micro is bad. Jump the relay and see if the HV comes up. It won't do much else, since the micro IC must be working in order for the tuner and the control circuits to operate. If the HV does not come up, you likely have other problems that could lead to a bad jungle IC, defective horizontal driver circuit components, defective power supply components, bad parts in the HOT area, or any combination of the above. Horizontal drive comes out of the jungle IC, to the horizontal driver stage, to the horizontal output transistor, and then to the flyback. A loss of horizontal drive anywhere in this chain means no HV.

If you get HV, you can feel a little better about changing the micro IC. However, I wouldn't be surprised if the tuner is toast and there could still be other damage to the set. Lightning is funny stuff that can do as little as blow the fuse and do as much a cook (literally) the chassis. I've had lightning damaged sets where it would be one part after another. Back in the day, it was usually worth the effort because a 27" TV was actually worth something. Now, I probably wouldn't go any further than the power supply before I bailed on it.

My new concern is if the EPROM requres any preprograming not covered in the SAMs. I am assuming if its a panssonic part number then it should have any basic program already installed? one more thing I assume I have to be careful of ESD damage when I get a new IC. Not checked out on that, but seem to recal folks where ground straps and have certing types of floor mats to stand on when handling them.

Do it on your porch or somewhere that the florida humidity is present-you wont have to worry about esd!