Admiral 16" Hybrid Color - No HV

[maxm]

I got this set at an estate sale in 2013 and finally took a look at it.
T7K101C chassis, in Sams 1182.

It has had some repairs done in the past, tubes replaced, one of the filter cans replaced and some soldering on the boards. Who ever did the work was kind of sloppy, it looks like they lost all the screws that secured the chassis and back cover and managed to find assorted replacements for half of them.

It currently powers on with sound, but there is no high voltage. I don't hear any noise from the flyback.

Unfortunately I don't have a lot of experience troubleshooting this stuff. I don't have the Sams, but can check at my library.

I would appreciate any advice.

Thanks,
Max

[Captainclock]

Originally Posted by maxm

I got this set at an estate sale in 2013 and finally took a look at it.
T7K101C chassis, in Sams 1182.

It has had some repairs done in the past, tubes replaced, one of the filter cans replaced and some soldering on the boards. Who ever did the work was kind of sloppy, it looks like they lost all the screws that secured the chassis and back cover and managed to find assorted replacements for half of them.

It currently powers on with sound, but there is no high voltage. I don't hear any noise from the flyback.

Unfortunately I don't have a lot of experience troubleshooting this stuff. I don't have the Sams, but can check at my library.

I would appreciate any advice.

Thanks,
Max

Did you check the HV tube? It looks like you might have a tube powering the HV and if that tube is weak or bad then you won't have HV.

[zeno]

Check the green bel-fuse first. Its the little square thing
by the damper tube. Also the flyback looks questionable
but had to tell in a pix. Looks like it got real hot. See if
it has a burned tar smell.

73 Zeno

[Findm-Keepm]

...and if you need a green Belfuse, lemme know. I've got at least one or two...

[Username1]

Looks Sanyo-ish ~ Who really made it ?

.

[dieseljeep]

Originally Posted by Username1

Looks Sanyo-ish ~ Who really made it ?

.

I have one of those! Made in Taiwan by Admiral Overseas Corp.
Most of the tubes are cheap, at the Florida tube place. AFAIK, those Admirals were the only one that used those odd-balls.

[drh4683]

Wow, that's a set you don't see! Glad you saved that one!

And i agree, certainly check the green belfuse. If it's good, I'd check to make sure you have proper negative bias on the HOT which would tell if the horizontal oscillator is running. I might have a tekfax for that chassis and will check later today.

As for who made it, Admiral always made and designed their own sets. In 1967, Admiral was one of the first manufacturers to open a plant in Taiwan, known as "Admiral Overseas Corporation" or "AOC" as it was officially called until Rockwell (who acquired Admiral in 1974) sold Admiral and the AOC arm in 1978. An eastern business group who purchased AOC changed the name to "AOC international" which still exists today.

This set looks like it has a lot of domestic parts in it even though it does indeed have a somewhat "Japanese look" to it. I've got a 13" version of this set from 1974 which was made in Taiwan and has a similar look with some domestic parts. This one could be a real deal Harvard, IL built set. I think Taiwan focused primarily on portable sets and radios while most of the big consoles were still built in Harvard.

Max, does the back cover have "Taiwan" molded on it?

[drh4683]

Ah ha! Dieseljeep replied as I was writing my first post. So this one is indeed an AOC made set, which is still a real deal Admiral designed and built set, just made in Taiwan.

[zeno]

IMHO this is a real US built Admiral. It screams Admiral.
The only AOC tube sets I remember were a 12" & 16".
They were very distinctive inside & out. You would never
guess Admiral with the back off. Of course they may have
set kits over at first like Zenith sent to some countries.
The layout of the set is the same. Funny thing is when
Admiral went away AOC sets looked like US built Admirals for
years & kept the same part ## scheme. The first few yrs
they were quite good. Then they used what we called Goodyear
FBT's. They were good for a year then went up in smoke.......

One other very common thing on both B&W and colors
was the hoz hold coil would get smashed in. We ordered
them & the shafts by the dozen. That will kill your HV
& maybe the h output tube.

73 Zeno

[drh4683]

Schematic photos attached.

IMG_20151031_125116070 by drh4683, on Flickr

IMG_20151031_125123334 by drh4683, on Flickr

[maxm]

Thank you for the responses and to Doug for posting the schematic photos.

It looks like there may be a power supply problem. I get very low voltages on all the tubes. It looks like there were some repairs to the power supply previously. CH8 and RE71 were replaced. The 3 diodes, RE70, RE71, and the green and black fuses tested OK. I seem to loose voltage around CRE3 and CRE4, but may not be measuring correctly, or misreading the schematic.

This set appears to have been assembled in the US, there are a few marked US components, including the white ceramic capacitors and the HV rectifier tube. There are a lot of foreign components, the flyback is from Taiwan, the power resistors are Matsushita. Back is not marked Taiwan, but nothing definitively identifies where it was assembled, though the model label lists Chicago.

The tubes are odd, it seems like they came out with a lot of new tube types for very specific applications right when things where changing to solid state. I had to find an updated test settings book for my tester to check them.

[zeno]

CH8 is high failure on any set that uses it. Its a voltage
doubler supply. I think I see it wrapped in tape.
If it were the right part it would be wrapped in cardboard
or sometimes plastic. The wrong cap will have a short life,
heat will kill it fast. For now you can hang a close value
cap across it & see if it comes up. If thats it our cap
expert can select the right replacement for you.

73 Zeno

[old_coot88]

Sure hoping the flyback is still good. Admirals using feedback-type HV regulation (which this one uses) were notorious flyback-eaters.

[maxm]

I'll unwrap the tape from CH8 and see what was used, whoever replaced it did a sloppy job and who knows if it was the right part.

The flyback does look like it got hot, but doesn't smell burnt or have obvious damage.

[maxm]

I took at CH8, it calls for a 350uf @ 200V. The replacement cap previously installed was 300uf. I took it out and it measured around 130uf. All the extra caps I have to substitute are lower values except for a 500uf. Could I use the 500 to test briefly?