Newbie.. is there a fix for this Sharp SQ-46P? - Videokarma.org TV - Video

obsolete man · #1 10-02-2021, 02:41 PM

https://www.radiomuseum.org/r/sharp_sq_46dsq46.html. I believe that is the tv I have, although mine is a P at the end, not a D.

Here is a video sample of the picture issues: https://youtu.be/kq9vkrIIh1A
Another sample: https://youtu.be/NRbsyMHtNm8

Base on the picture, the snow, the lightning effect, etc. Do you see any telltale sign of anything that we can pinpoint?

Set-up is a fire stick to HDMI to RCA adapter to RF Modulator to 75/300 ohm adapter to the two terminals on the tv's VHF. I have another TV in the same era, late 70's Zenith, that's producing a clear crisp picture under the same set-up. But I just can't focus this Sharp. Here is the Zenith with a great picture under the same set-up: https://youtu.be/rxd6hPlz4Kc

Do you guys think better video delivery equipment would help? Or, will the Sharp TV need surgery, as in opening it up. LOL! I don't have technical knowledge, or even know much lingo about these things. I just started getting old tvs out of nostalgia. So if you advise me, please talk to me like I'm a 5 yr old. LOL!

I've asked for help in other forums too, but I see videokarma at the top of search engines, so I figure I'd ask for help here too to gather as much knowledge as possible. Thank you for your time.

Electronic M · #2 10-02-2021, 03:00 PM

There's 3 issues I see that have varying degrees of difficulty to fix.

Easy. You may be able to improve the sharpness of the picture adjusting the TVs fine tuning control.

Intermediate. The snow in the picture is probably dirty contacts in the tuner. To fix it that you'll have to disassemble the set enough to get to and remove the VHF tuner shield then spray the moving contacts with tuner cleaner and rotate the channel tuning knob several turns in each direction.

Hard. It looks like the horizontal deflection circuit is intermittently failing and coming back. This requires soldering skills, troubleshooting skills and circuit theory knowledge. If the horizontal stays collapsed for too long unobtainium parts can be destroyed.

obsolete man · #3 10-02-2021, 03:27 PM

Quote:

Originally Posted by Electronic M

There's 3 issues I see that have varying degrees of difficulty to fix.

Easy. You may be able to improve the sharpness of the picture adjusting the TVs fine tuning control.

Intermediate. The snow in the picture is probably dirty contacts in the tuner. To fix it that you'll have to disassemble the set enough to get to and remove the VHF tuner shield then spray the moving contacts with tuner cleaner and rotate the channel tuning knob several turns in each direction.

Hard. It looks like the horizontal deflection circuit is intermittently failing and coming back. This requires soldering skills, troubleshooting skills and circuit theory knowledge. If the horizontal stays collapsed for too long unobtainium parts can be destroyed.

I think Easy has been tried. I played with everything on the tv including the fine tune knob. Maybe I'll give Intermediate a try. But I just thought of something. I've been looking at agile modulators that send wireless signals. If dirty contacts is the issue, would that effect wireless reception too?

I hope the issue isn't under your HARD category, that would mean this TV will just be a display prop. LOL! BTW, in the videos you see, there is a shadow moving down that's not present in real life. What is the technical term for this?

Electronic M · #4 10-03-2021, 12:53 AM

Easy and intermediate cover your initial question. Hard is present in the video if I'm interpreting what I see correctly and it may eventually kill the set.

The dirty tuner issue should affect the picture regardless of the signal source.

Rolling bars in the video that you don't see in person are called shutter bars....they are caused by the frequency and phase of the video camera shutter and the vertical sweep of the TV being out of sync.
Tons of small lines are a related phenomenon called moire. This explanation is more funny than anything I can come up with. https://xkcd.com/1814/

zeno · #5 10-03-2021, 02:02 PM

The main problem seems to be the hoz osc. It goes off freq
& then collapses. It may be a cold joint, dirty control or electrolytic.
Hardest thing on these little sets is physical servicabillity.
Numbers from Sams often dont match & the PCB's are usually only marked
on the top. Add to that the crowding...
Good news is CRT looks strong & should come out nice.
Bad news is my SAMS manual is missing so you will have to find one
to continue.

73 Zeno

LFOD !

obsolete man · #6 10-11-2021, 01:47 PM

Got rid of the snow with a better modulator. But the horizontal collapse is still there.

How much does a repair like this cost if I were to take it to a service person?

zeno · #7 10-11-2021, 03:29 PM

Odds are you wont find a TV man. We are almost all dead or retired.
20 yrs ago you would probably pay $50 - $75 but with its age many wouldnt do it anyway.

73 Zeno

LFOD !

Quote:

Originally Posted by obsolete man

Got rid of the snow with a better modulator. But the horizontal collapse is still there.

How much does a repair like this cost if I were to take it to a service person?

obsolete man · #8 10-12-2021, 03:30 AM

Quote:

Originally Posted by zeno

Odds are you wont find a TV man. We are almost all dead or retired.
20 yrs ago you would probably pay $50 - $75 but with its age many wouldnt do it anyway.

73 Zeno

LFOD !

I saw a little doc on Chi-Tien Liu, and I was a little sad to learn he's in his 80's. I hope he has or had some pupils that he passed his skills onto.

Electronic M · #9 10-12-2021, 12:07 PM

There are a lot of people like me (not 30 yet) who restore the old tube era sets as a hobby, and some in the gamer community who focus on maintaining solid state sets (that I mostly regard as uninteresting chicom junk).

obsolete man · #10 10-12-2021, 02:14 PM

Quote:

Originally Posted by Electronic M

There are a lot of people like me (not 30 yet) who restore the old tube era sets as a hobby, and some in the gamer community who focus on maintaining solid state sets (that I mostly regard as uninteresting chicom junk).

That is awesome! You're younger than me. I know there are people and clubs out there. Zeno is just a little pessimistic.

DavGoodlin · #11 10-20-2021, 12:53 PM

Location is everything so, if you're close to one of us, we would definitely have a look at this.

I suspect you have an electrolytic capacitor issue by the look of the sweep failure.

Remember the 80s advertising for Sharp: "from sharp minds come sharp (but mediocre

) products"

zeno · #12 10-23-2021, 10:09 AM

Trouble is unless you are in a big city there are almost no classic
TV shops left. The few that are have to charge too much to
make a real living. Its a labor of love so see if you can find a
hobbyist.
One of these cats from UTUBE may help you if you send it to them.
shango066
jordan pier
radiotvphononut

If nothing else they have great repair videos you can learn from.
Even a few recaps on small asian TVs

Good Luck
Zeno

Quote:

Originally Posted by obsolete man

That is awesome! You're younger than me. I know there are people and clubs out there. Zeno is just a little pessimistic.

obsolete man · #13 11-11-2021, 06:02 PM

Hey guys, what are some questions I can ask an online seller to insure the best chance of getting a working tv? Most sellers now will say a tv is good simply because it turns on, and that they can't do any testing because there are no longer analog signals.

Since I've learned about this horizontal collapse, I now ask sellers to observe the static for me. If there is horizontal collapse when a good image is received, then there should be horizontal collapse with the static too, right? Anything else a seller can check for me? If they don't get static, but a white screen, is that tale tell of a bad tv?

Electronic M · #14 11-11-2021, 08:48 PM

A blank white screen could be a dirty tuner.

Tube TV · #15 12-15-2021, 02:31 PM

Agreed with what everyone says. I'm also seeing a intermittent horizontal failure.
I'm suprisied that it has as good of a picture as it does. Usually the electrolytic caps in those early transistor sets are getting pretty leaky and dried out.

The horizontal issue could be a weak solder joint.
You could poke around the horizontal oscillator circuit and look for a change in the picture. (Use a plastic stick pen or something no conductive)

Also how many turns can you turn the horizontal hold control?
Some of these TV's have a control that is a pot (which is the same as a volume control) and if this is dirty and losing connection you would have the collapsing issue also.