Sharp Lyntron 9" Color TV Model 9H102 AC/DC TV Clicks ON But No tube (snow) or sound
 

Hello,

My first posting of this may have incorrectly been put in the Introductions so I've copied it to this section since this is a mid 1980s 9" CRT TV. The original posting link is here: http://www.videokarma.org/showthread.php?t=272920

I'm new to this forum and just learning my way around.

I'm the original owner of this Sharp Lyntron 9" Color TV 9H102 AC/DC TV. I have the original user guide, DC plug for running the TV from a car battery 12 V.

I purchased this unit new in about 1984. It ran for many years and then stopped.

I can't remember but I always wondered if it stopped because our house power went out and I seem to vaguely recall that's when it wouldn't turn back on again. But I'm almost certain I had the TV plugged into a Surge protector, so I was skeptical if it was a power surge that caused the problem.

I kept it all these years because I didn't want to get rid of it, thinking I might be able to get it working again some day. At the time I didn't take to a TV repair because I don't think there were any repair shops in my area that even worked tube TV's at that time...

But recently I found out about this forum and thought I should give it a try.

Please let me know if you can help me get it running. I have a very basic knowledge of electricity. I can use a multi-meter and can check voltages. I can also test diodes and transistors and do basic things like continuity checks.

The symptoms are:

The on/off switch clicks on and off with a distinct click, but the TV tube won't come on (light up) (it appears to stay dark, no snow and no sound through the speaker you typically get when you plug in a CRT TV without an antenna hooked up).

Any idea where I can find the service manual for this TV in case someone asks me to check some wiring? I'm wondering if the schematic diagram is inside on the case. Maybe I should carefully take case off to look, not touching the tube, though...

Try it on both AC & DC cig lighter cord first. Its been years but IIRC
there were no unusual circuits in it, thats good. After that pull the
back for a good lookin over. Burn spots, blown fuses, loose plugs
etc. Do not worry about the HV ! Even running its probably no more that
12 KV & wont hurt anymore than .001 % of people. It probably bleeds off
in a few seconds anyhows. Unfortunately no 9" Sharps are covered
in Sams. The OEM manual is the only one but BEWARE if you buy one
that you get a real manual !! After the above checks take a few chassis pixs
& with luck we can walk you through it. Odds are its not a tough repair.

73 Zeno:smoke:
LFOD !

Hello Zeno,

Thanks for replying. I'll do the things you say tomorrow morning. I've only tried it plugging in the AC power cord. I haven't tried the DC power cig lighter yet. I'll try that. I'll get some really good photos for you to look at. Are there any fuses inside the chassis? Are they the round cylinder glass fuses with the metal on each end? I may be dreaming, but several years ago I think I took off the cover and I might have seen a schematic on there, but I kind of doubt it. Get back tomorrow...Thanks...

Any fuses should be the ones you described. As a rule if they are black they died violently & you have a dead short. Check them with an ohm meter.
Sometimes they break at the ends & you dont see it. In that case
they have usually died of old age.

73 Zeno:smoke:
LFOD !

Hi,

I took several photos and will post them tomorrow. It had 1 4A fuse that I could see and it checks out for continuity across the fuse with my multimeter. The fuse looked clean and I could see the fuse wire clearly in the glass. I tried to start on DC with 12v cord plugged into the DC power and connected to a 12 v battery and the same symptom, the unit would Click like it wants to go on but no tube lighting up. When you click the unit again it clicks OFF like it's supposed. Just not getting the picture tube and sound to click on. The one fuse I found checks out OK. Don't see any other glass fuses in there at this time...Thanks for your advice...

Here are the photos of the unit.

I can give you more photos of specific sections. Just let me know. Thanks...

Hello,

In examining the components visually, I noticed a fairly large capacitor on the bottom most board the capacitor had a definite bulge look at the top such that it appears to have expanded. I wonder if that capacitor is bad and maybe this is my problem. Here are 2 photos of the same suspected bad capacitor. Any advise is appreciated.

The cap needs changing but may not be the problem. Change it.
While the PCB is out check under the power connectors for cold or cracked joints. Also the small board beside it has a fuse. Check soldering under that board also. To take apart remove the screws marked with the screw symbol.

good luck
Zeno:smoke:

I'm not sure how to remove the pcb, it's the bottom one not one on the sides. I think I need to place the unit with the tube facing on the bench and then try and remove screws. There were 2 fuses and I checked both of them for continuity and they both seem OK. Not sure I can remove the pcb. There connectors to the main tube and unsure what to do with those. Might be more than I can handle.

The bottom probably comes off & the other boards fold to the sides.
Everything plugs in so you can unhook short ones. You can also cut wire ties often to get more wire.
Remember start with the screws marked with a screw symbol !
That symbol means " take me out to take me apart".

Thanks, OK I'll see if I can give it a go. The little tv looks like the thing is fairly complex in getting to things. I see the little screw symbol and will concentrate on those.

Does a house power surge blow the tv picture tube very often? Just curious.

There's usually several layers of power supply/protection between CRT and power line in a solid state set. A surge will usually take out the bridge rectifier and parts in the power supply of solid state sets. If lightning hits the antenna the tuner balun will fry and possibly other parts in the tuner.

If you're worried about the CRT you could unplug it and hook a 6V lantern battery across the heater pins. If the heater lights it's probably all good.

Thanks Electronic M for joining the conversation. I don't think we had any lightning since ours is a low lightning area, hardly any at all...

But our power company does have occasional outages and then they turn on the power and I wondered if that what was caused the problem. It was so many years ago that I truly don't recall but I think over the years we may have had a few smaller crt tv's go out after a power outage.

I kept this little tv since I really liked the dual voltage 12 v and 120v.

Not to change the subject but we had a small tv with a vcr built in the bottom and I got rid of it about a year or more ago because it was eating tapes, before I discovered there were forums like this that might be able to help get it working.

I don't have a 6 v battery and it would be hard for me to put it across the heater pins because I don't know where they are since this is the first tv I've ever tried to fix.

If you have any other suggestions I'd appreciate it.

In the back of my mind there is that swollen capacitor up in post 11 and for some reason I wonder if that's the cause of my problems...

That capacitor is a red flag. I would replace it before anything else, then you'll know for sure whether it was or wasn't the problem.