Emerson ECR1350 cold start issue
 

Hello all,

I recently acquired an Emerson ECR1350 13" TV from a local thrift shop. I asked the shop owner if we could test it, since he had several cable feeds for other TVs. The set came on and had a good picture, so I decided to buy it. I didn't have much to lose, since he only asked $15 for it.

At home, however, I began to experience a problem with the set turning on. When I push the power button, I could hear the relay click and the tube power on. But then the set turned itself off very quickly, and a relay (or circuit breaker?) began clicking inside. Unplugging the set and plugging it back in cleared the clicking, and playing with the power button resulted in the set coming on and staying on. I shrugged this off at first, because it only happened occasionally, and I figured that it was just an old thrift store set.

Tonight, however, it took me quite a while to get it to come on. The set would come on, click back off just as the picture warmed up on the screen, and the internal clicking could be heard. Unplugging it did not clear the issue, and only after turning the set on and off for several minutes did it finally turn on and stay on. When the set is on, there are no other operational issues. The picture is uniformly lit and the color is excellent and smooth (I tested the TV with a test-pattern DVD). There is nothing noticeable in the audio, either.

My suspicion is there is a weak relay in the power circuit or some internal circuit breaker is tripping, but I am not 100% sure. The set does this whether it is cold or has been on for an hour or so. I am an electrical engineer-to-be, so i have some experience with electric circuits, but I figured I would ask you guys first to see if you have any ideas or suggestions on where to start looking. I do have the service manual coming, just in case.

Any and all help will be appreciated. Thanks!

Since the set works well otherwise, I would look at electrolytic capacitors in the power supply. There is no circuit breaker inside and the relay is likely alright. It is most likely a capacitor issue if the set is old. Also check for bad solder joints around the power supply components. That should give you enough to get started.

Look for bad solder connections in the power supply and/or the horizontal driver and output circuits. Also, check the electrolytic caps in the power supply. That clicking sound you hear is coming from the flyback transformer and is normal when these sets go into shutdown.

Thanks for the suggestions! I'll take a look at it as soon as the service manual arrives.

I think the capacitor suggestion is a good start, because when I'm trying to turn the set on, it feels like I'm starting a temperamental motor; just as it comes to life, it runs out of juice. So far I haven't been left "stranded", but it certainly is not getting any better.

radiotvnut, what would cause the flyback transformer to click? I'm interested in learning these symptoms so that I can do my own troubleshooting in the future.

Those are pretty good sets, the ECR1350s. I've been trying to locate one for nostalgic reasons.

My grandfather used to have one of these. He got rid of it sadly.

I don't fully understand it; but, I think the clicking sound has to do with loss of power supply regulation; which, trips the HV shutdown circuit. This shuts down the horizontal drive and I think this is one of those sets where the drive keeps trying to come up; but, the shutdown circuit will keep shutting it down until the problem is fixed.

If you have access to a variac, try powering up the set at 90V or 100V. If it comes on every time and stays on, you have a power supply regulator problem. If you don't have a variac, plug the set in series with a 60W-100W incandescent light bulb.

IIRC, those sets had a weird SCR based power supply, similar to Sharp TV's.

Those sets had really nice pictures on them; but, you might want to find a new flyback to have on hand as a spare. Back in the early-mid '90's, I replaced a lot of fly's in these sets; and, that was when they were 5-7 years old.

radiotvnut, that makes sense, because when the HV shutdown occurs, it probably trips an internal relay, which makes the clicking sound.
Could you explain the lightbulb in series thing to me? I think I know what you are talking about, using the lightbulbs to control the voltage reaching the TV, but I just want to make sure of the procedure before I do it.
Also, I just got the service manual for this set yesterday, so if I am correct to think that SCR means "silicon-controlled rectifiction" then oh yes that power supply is definitly an intersesting one!

I just returned to college a couple of weeks ago, so I'll have to wait to the weekend before I can open this set up, but I'll keep you guys posted. I am glad to hear that my $15 "junker" is a good set. I am very impressed with the picture quality of this thing so far. It compares very well with our Sony Trinitron set (21 years old and still going, knock on wood).

The light bulb is wired in series with the AC line. Connect the hot side of an AC power cord to one terminal of a standard light socket. Connect the other terminal of the light socket to the hot (narrow blade) side of the TV power cord. The neutral side of the AC line will connect to the neutral side (wide blade) of the TV power cord.

Also, be aware that the metal chassis frame and the heatsinks are hot (live). It would be better for you to plug this TV into an isolation transformer if you power it up out of the cabinet.

It means Silicon Controlled Rectifier. See:
http://www.radio-electronics.com/inf.../thyristor.php

Thank you, radiotvnut and old_coot88, for your helpful information. That article was quite good, and I also feel confident about the light bulb technique.
Unfortunately time was not on my side this weekend (control systems block diagram reduction homework takes FOREVER) so I did not get to open the set up yet. I'm hoping to get to it soon, but college comes first...

Anyway, the set now just turns on for a second or two and then shuts off, no matter what. The tube powers on and attempts to stay on, but it shuts back down quickly.

I have a question regarding the capacitors:

Do failing capacitors smell something like fish or ammonia? When I first fired the set up at home, it let off a REALLY ammonia-fishy smell. I shrugged this off as just being the smell of the thrift store impregnated in the plastic, but now that I thought about it, the smell was present only when I had the start-up issues. Once the TV was on and running, the fish smell went away quickly.

OK, I'm back.

I FINALLY had some time to to open 'er up tonight and take a look. Not much to report; nothing visibly looks burnt or damaged, so I'm going to start to look at the capacitors in the power supply section of the board.

There are 10 caps that may be the culprit: C502, C506, C507, C508, C509, C513, C516, C518, C124, and C126. The rest are ceramic caps, but the interesting one is C511; when I found its number on the board, there was never a cap attached there!

The attached scan is the service manual page for that section (its towards the bottom), in case you guys find something else I should look at on there. I am going to try the home-made variac soon now that I'm on spring break, but any other thoughts or suggestions are welcome.

The smells you are describing is that some of those electrolytics are getting "ripe" and leaking. As for the missing cap, either there was a revision change or to maybe put caps in parallel to get the desired values depending on what was available on the production line possibly.

Look at the electrolytic caps. They have a crease mark or marks on the exposed top of the aluminum can which is designed to break open and allow a controlled release of pressure rather than a pop when they go bad. Really bad ones will have opened enough to ooze goop either on top or around the bottom of the cap. Don't confuse the ooze with sealant sometimes used to anchor caps to the board. Ones going bad will often bulge the top. Tops need to be completely flat to be "probably" OK.

If you search on line for images of failed electrolytic caps you'll find lots of pictures of them. Here's an example of a good one and a bad one side by side. Sometimes the bad one will have oozed its orangish innards out.

https://us2.ixquick-proxy.com/do/spg...loatedcaps.jpg

Well, tonight I finally got to make a DIY variac per radiotvnut's suggestion, so here is what I found:

I started out with a 75W light bulb in series with the TV set. The first couple of times pushing the power button the light bulb came on brightly then went off quickly, accompanied by one clicking sound inside the TV per push of the button. The third time, The TV came on and tried to stay on, but clicked off after about 2 or 3 seconds. The bulb lit up simultaneously and continually dimmed in the same period, and then went out. The fourth time, the set came on and stayed on, with the screen reaching full brightness and the speaker outputting static (the set was on a blank channel). The set continued to stay on, but the screen was flickering, bending, and rolling badly, and the light bulb was dimming up and down. Pressing the channel button made it worse, to the point that it was almost completely shutting off in between flickers. I assumed that this was due to the voltage being too low, and so swapped the 75W bulb out for a 100W.

With the 100 watt-er, the first couple of times the set clicked on and off, third time it came on and shut off after 3 seconds, and the fourth time it came on and stayed on. This time, the screen was much less distorted while nothing was being pressed, though I noticed that the volume went down ever so slightly while it was just sitting there. The light bulb remained in a steady, half-way dimmed state. Pressing the channel button sent the unit back into it's flickering, distorted mode, with the set alternating between a twisted, flickering screen and nearly shutting down; the light bulb dimmed and brightened during this time as well.

Just for reference, I plugged the set into the wall, bypassing the variac, to compare results. Plugged straight into the wall, the set would come on, stay on with volume, but the second I press the channel button it shut right off. A few weeks ago it wouldn't even stay on, so I'm not sure why tonight it stayed on until I pressed the channel button (the only thing I can say is that it was unplugged for the last two weeks).

Anyway, this is the info I currently have. I did look at the board again before I put the case back on for testing, and I did not see any noticeable bulging or crease breaks in the caps. I'm still going to look into new caps though, since I definitely smelt that ammonia smell when the set was first in my possession.