1989 ADC , getting no picture
 

Well I picked this up today, cleaned it up, hooked it up to my cable and plugged it in. I get static, but no picture at all, just static.

I tried playing with the tuner, every channel. Moved the (vhf to cable) adapter from vhf to the uhf, no difference.

There is zero change in the tv when it's hooked up to cable, as when it's hooked up to nothing.

Any ideas what may be wrong with this?

https://i.ibb.co/wRqz1Sy/IMG-20201212-180647.jpg

https://i.ibb.co/GJrsYCV/IMG-20201212-180710.jpg

https://i.ibb.co/CnhQnsQ/IMG-20201212-180741.jpg

Most cable TV is digital and all TV on antenna is digital. You need a cable box meant for analog TVs (some cable companies offer them if you ask) to watch cable.

Do you have a working VCR or old video game console? If you do then see if the TV will tune that. If the TV works with a different signal source then the TV is fine and your cable is not set up for it.

That set was made in July of 1989.

That might be one of the oldest "Made in China" TV sets I've ever seen!

Its a very early one. First Chi-Com sets I saw were Crowns about this time.
Terrible sets.
This one is a strange beast. Its an AOC which started out as
"Admiral Overseas Corp" a Taiwanese division of Admiral. When Rockwell
carved up Admiral AOC got bought & continued building sets. The chassii
were a continuation of the Admirals right down to the parts numbering
system for abt 10 yrs. One set was the first 19" to retail under $200 I
saw. That set ate up every FBT in about 2 yrs. Other than that they were
good running & well built sets. Now this set we see two arch enemies
doing business together, interesting....

73 Zeno:smoke:
LFOD !

It's AOC not ADC on the logo? This is an Admiral?! Dang that's cool.

I forgot to state that I'm using an xfinity comcast digital/analog cable box, it works fine on the 1964 Zenith b&w 19" in my living room. So this should be providing a good signal to this little tv.

Though just for "I'm gonna try everything" I'll attempt to use a vcr to provide a signal to this tv.

Here's a better photo.

https://i.ibb.co/rfdj2VY/IMG-20201213-151059.jpg

Definitely BPC era. Are you getting high voltage? CRT filaments lighting up? Video output maybe not working.

I broke out my VCR, tested it on a 1997 Panasonic 21", so the VCR still works.

Yet when I tried the VCR signal on the AOC I get Nothing. The screen is still just static. There is zero change to the screen or volume when it is given a signal, or when nothing is connected.

The screen is just static, so I assume that the high voltage is still functioning. I peeked through the vent in the case and the rear of the crt is lit up.

So it seems like something is wrong in the video section? I'll open the case tomorrow and see if anything is obviously wrong.
https://i.ibb.co/zn3B1P5/IMG-20201213-161434.jpg

In the first photo, your lead in wires are connected to the UHF terminals. If it is really like that, Move them to the VHF terminals (lower two screws) and I bet you a beer it makes a picture.

If it isn't that, time to go inside. Sharp snow on the screen tells me that the whole thing is working though.

I tried the VCR connected to the VHF terminals.


I had originally tried the digital/analog cable connected to the VHF, then when I got no response I'd tried it also on UHF.

Does the look of the snow change when you rotate the channel selector knob? And do you ever get sound?

Not quite an Admiral but a direct descendant. Its like if you have an AMC
car it is a descendant of Hudson & Nash. Had history played out different
an AMC car may have been a descendant of Packard, Studebaker, Nash
Hudson & maybe Checker Cab Cars.

Now for your problem. As a rule if a set comes on & has a hiss in the audio & a "snowy" picture it is probably working. The input should go to the
VHF terminals NOT the UHF as shown. Then usually it will play through
channel 3 but in rare cases ch 4 or 6.
If you just kind of get something try the fine tuning. Its the knob within
the VHF selector knob. It can turn quite a few times either ways.
Usually its a push in & turn.

73 Zeno:smoke:
LFOD !

The screen is snow and the audio is just a hiss. I've tried it on every channel and played with the fine-tuning for every channel while doing that.

It's currently using the VHF input, I only tried everything again on UHF because I wanted to try every combination possible. There is no picture whatsoever, no hint of audio.

I pulled the back off and did a quick look, there's no obvious problem. No swollen caps, no burns on the circuit board, no burnt smell. I was semi surprised to find out that it uses a Samsung CRT.

Tomorrow I'll pull the board and give it a real look. Outside of checking to see if the caps are still good... I'm not sure what to do.

https://i.ibb.co/Xx2zxY9/IMG-20201213-172535.jpg
https://i.ibb.co/jbS4Q7w/IMG-20201213-172702.jpg
https://i.ibb.co/yFr5C9s/IMG-20201213-172228.jpg
https://i.ibb.co/KNkGnyk/IMG-20201213-172306.jpg

Clean the VHF tuner contacts

The coax going into the back of the tuner looks damaged.

+1
If a set has snow but doesn't tune a known working properly connected analog RF source then dirty tuner contacts are likely. (open the shield and spray contact cleaner on the contacts on the rotary drum or switch wafers)

What's going on here? Can we get a closer picture?

https://i.imgur.com/pqJ3rb4.png

That connector (goes from the VHF screws to the tuner) is ugly and frayed, it been tested and still has continuity. It appears as if it was just that ugly and badly made at the factory. I can replace it tonight, just for the heck of it.

I opened the tuner and while it looks okay, I will pick up some contact cleaner for it tonight.

https://i.ibb.co/YjgJn0z/IMG-20201214-150604.jpg

Dont forget this is a HOT chassis set. If you dont have it on an isolation
transform you may see sparks ! Be SURE to replace anything in the antenna
input with the same type thing. There is probably a small box or seperate
parts on the antenna board. That is for isolation & shouldnt be compromised.

I discharged the crt, removed the ugly cable and replaced it with an RCA cable.

I've yet to clean the tuner, Lowes was out of contact cleaner. Supposedly they'll have it by the weekend.

https://i.ibb.co/jGf48x8/IMG-20201216-012956.jpg

We used to see dead tuners on occasion, but you need to verify the DC voltages first. If you can get a schematic, look for the B+ and AGC voltages on the top of the tuner terminals. If either is missing, you'll get nothing.

John

So.... the tuner was cleaned, no change. Not a hint of video or audio, just static. I'll keep trying to find a schematic and then check the voltages.

I found another for sale, figured I'd get it for parts. This is an Amark, made by AOC, obviously the same exact tv, only made one month apart and the ONLY internal or external difference that I can find is the branding.

It has the SAME problem (whatever the issue may be). So yeah.... WHEN I figure out how to get one working I will have an extra set for parts. Though right now I'm just frustrated.



https://i.ibb.co/rb1GxHs/20201222-213916.jpg

https://i.ibb.co/6wLSs4d/20201222-213153.jpg