Zenith 12H090 - Printable Version
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+--- Thread: Zenith 12H090 (/showthread.php?tid=18454)
RE: Zenith 12H090 - EdHolland - 02-18-2019
I forgot one thing - the little oscillator/preamp for the phono input. Even though I don't plan on using it (it only plays 78's), a restoration is a restoration. 3 caps in a little tin box about 2"x3"x3". Two paper types completely hidden from access by the riveted tag strips, and a twist lock electrolytic to restuff. Fiddly, but all done.
The chassis parts have been packed up carefully ready for next week's trip, thither they will return to the cabinet. I'll also take a basic radio first aid kit, just in case, and try to get some pics of it all.
Cheers
Ed
RE: Zenith 12H090 - EdHolland - 02-23-2019
We made the 300 mile journey safely today, and I set about refitting the chassis - what an adventure!
First off, I had forgotten that the mounting adaptors (pics later) needed substitutes for the rubber grommets which attach them to the chassis. I reasoned that this could be achieved with tubing, and set off fo the hardware store. First attempt just too big.. so back to the store later when we went shopping for dinner. Meanwhile I cleaned up the dial cover window and surrounding cabinet area. With the right materis and adaptors ready to go I was reminded just how fiddly it was to remove the chassis.. because..
That was nothing to getting it back in. On this console the radio chassis is mounted on a cantilevered pull-out drawer affair. Even to get it close requires removal of the magic eye, and a contortive manouver. Then it has to be arranged into place, with the control shafts through the panel, and screws engaged into the adaptors to hold it in place. Then the tone and preset control switch banks must be fenagled through the space either side of the dial, before the dial cover/escutcheon is attached. I got all the way through this, before realising the bandswitch indicator was not visible. Off with the escutcheon to correct the felt dust guard. As I was replacing it, I dropped the first of the small woodscrews, which seemed to fall in to the chassis. No sign of it on the floor or anywhere else. Must be trapped in the chassis. Harsh words were offered, affording stern looks from Mrs H across the room. Chassis out palava, still no sign of screw. More involuntary invective offered to the gods of fate. Screw then found where it fell inder the cabinet despite the earlier search. The next attempt is successful, and I was able to follow with addition of the PSU/amp chassis.
Speaker and antennas connected, ready for power and... life! It sounds much better with the original speaker compared to the bench test. Broadcast band/MW antenna circuit alignment needs touching up with the wave magnet connected, but that is easy
With good FM signals (not in my basement/garage) reception is clear and pleasing.
As promised, I will follow up with some pics. A long day of driving and radio fiddling.
Cheers (tired) Ed
RE: Zenith 12H090 - OldRestorer - 02-23-2019
Please do!
I had one but the CobraMatic was a pain... I gave it to a radio friend last year. The cabinet was beautiful with a perfect Photofinish.
Cant wait to see yours all back to life!
RE: Zenith 12H090 - EdHolland - 02-23-2019
Right, pictures:
Here is the method I used to refit the mounting bars. These suspend the radio chassis in the pull-out drawer.
I used two sizes of clear tubing (one fits within the other) to make a substitute grommet. This makes a good snug fit between the peg on each bar, and the 7/16" hole in the chassis.
RE: Zenith 12H090 - EdHolland - 02-23-2019
Through the magic of the internet, all you have to do is scroll down a little to complete the arduous task of replacing the magic parts inside the wooden boxy thing.
Here's the furniture aspect:
And here is the "Magic of FM". Instructions direct the user to adjust tuning until the bars on the eye are evenly balanced. The top bar is fixed, the bottom bar (connected to the discriminator) expands from the right side as one tunes across the signal, indicating the position of the station center. On AM, the whole eye works together, opening and closing from both sides.
I'm demonstrating here on the 100 mc/s band, as there seems to be an interruption to the programming on Captain Armstrong's stations around 45 mc/s.
RE: Zenith 12H090 - EdHolland - 02-23-2019
On the other side, the drawer opens up to reveal the Cobramatic phonograph. Here, we have a couple of problems, and some creative input from Mrs H. The turntable is missing a needle, and will only play 78's. add to that, yet another long harness filled with crumbly rubber wire. Amongst the other things we seem to have accumulated going through life is a "Nu Tone" turntable, sold as a cheap way to digitise your vinyl. It is a good fit in the space occupied by the Cobramatic turntable, which has been delicately removed, and will be preserved for a possible future project. All changes are completely reversible, so (in my book) don't count as mods.
The next project will be to fabricate a board on which the newer TT will sit, and also to contrive a means to connect it into the main audio circuitry of the receiver. I will need a connector suitable for the radio chassis, if cannibalising the old phonograph harness is not desired. Mrs H really wants this to be usable for records and radio, and I think this is a great compromise
RE: Zenith 12H090 - OldRestorer - 02-24-2019
Thats fantastic....
Great idea on the tubing!
My finish was crazed pretty good too but I sprayed some clear over it and it helped a good bit.
RE: Zenith 12H090 - EdHolland - 02-25-2019
Thanks!
The whole family loves this one, and we enjoyed it a lot over the weekend.
RE: Zenith 12H090 - jcassity - 02-25-2019
that is really neat,,
i think i can get one of these sets for free,,,
sitting in a big house in canton ohio....
i keep telling her to post it here as a "come and get it" add.
RE: Zenith 12H090 - tbone - 02-25-2019
What a beauty! It looks really cool all lit up and I’ll bet sounds excellent.
RE: Zenith 12H090 - Arran - 02-26-2019
Ed;
I would be inclined to repair the original phonograph, if it is cosmetically in good order. From what I can see those players with the cobra tone arm would have a stylus pressure that is fairly light, so they are pretty good units so far as 78 rpm changers go. Even though you do have a limited selection in terms of music genres, there are a lot of 78 rpm records around everywhere, so it is a fairly practical record format, unlike something an Edison cylinder. I'm not sure about the Nu Tone replacement, some of those MP3 conversion machines are junk with a wimpy DC motor, kind of like those horrible China "crosley" units they sell.
Regards
Arran
RE: Zenith 12H090 - EdHolland - 02-26-2019
Arran,
Thanks for your comments. Restoration is not out of the question, by any means.. although I don't know about obtaining a stylus/cartridge for the tonearm. The "replacement" is temporary - I am sure it is not the best quality, and would have sooner used a better turntable in the console, but Mrs H wants to play with the console, and it was given to her originally.
Nothing will be hacked up, modified or discarded, so returning to the original factory setup will always be possible - that was a priority. In the mean time, the other unit will provide a fun diversion, and we have lots and lots of music on LPs.
Cheers,
Ed
RE: Zenith 12H090 - OldRestorer - 03-19-2019
I found a pic of mine!
RE: Zenith 12H090 - EdHolland - 03-19-2019
Nice!
Thanks for sharing that
These are, perhaps, not my favourite radio so far for "playing with a radio" - but I'm a shortwave nut. Where it really hits the mark - and I am so pleased it does - is right where it was supposed to - home entertainment. The FM sounds great, and pulls in all the stations. At the place we keep this radio, it will get used for many years to come, and it fits the old style house perfectly.
RE: Zenith 12H090 - EdHolland - 05-26-2019
I have a question for the experienced folks here... How hot is too hot?
We have enjoyed a pleasant evening listening to the Zenith, and I now find the power transformer is far too hot to hold for me to hold my hand on it. Certainly it isn't 100 C boiling hot, but probably well above 50 C. Not a level of heat that seems right to me - I would expect warm, but not hot...
I may get under the chassis with a voltmeter tomorrow and check voltages in the power amp, see if anything is wrong e.g. output tubes and such.
The radio sounds fine, but I am worried that there is a problem lurking.