Zenith Allegro Stereo Console b966 Refurbish/Remodel

Hi all. I just bought a Zenith Allegro Solid State Stereo, b966. The whole thing turns on immediately when it's plugged in, regardless of if the 'on' switch is flipped or not. The radio/stereo receiver lights up and works, but when the radio plays through the speakers, it sounds tinny, and is much stronger in the right speaker and sometimes doesn't even play through the left speaker. The 8-track player doesn't work at all, neither does the record player. The speakers make all types of noise each time I move the volume knob or slide the other knobs (bass, treble, left-right, etc.).

I plan to try and fix and keep the record player, just swap the needle/cartridge out, although I may just replace the turntable with a new one. The 8-track is coming out, and I'd like to put something modern there in its place, like a Bluetooth doohicky. The stereo receiver is pretty cool and I'd like to keep that, too.

My questions are
(1) Most importantly, what's causing that noise, and can those speakers be fixed? I've read that this model of Zenith stereo system had great speakers, so I'd like to save them if possible. Even slight moving of those knobs makes the speakers spit and crackle something fierce, sometimes even shaking the whole console. I imagine that means that they pack a punch when they work right! I'll get new ones if I have to though.

(2) Is it possible to hook up new equipment to the stereo receiver? Like if I took that tape player out, could I hook something else to the port/aux it was in? Same with a new record player.

(3) Is it worth saving the record player (which has a 2-gram non- adjustable tracking mechanism) or should I just replace it?

I'm a college student who isn't very well-versed in vintage electronics, so you may have to simplify some of your tech jargon! Thanks!

 

Repair it properly, get it working. It is a decent last ditch decent Zenith.

 

Any chance of a picture of said unit?

What size woofers etc?

 

I'll get some pictures in this afternoon, but I believe the woofers are 15". And I'd like to repair it, I just don't know where to start.

 

Start with cleaning, spray contact cleaner like holy water in every switch and control.

 

Maybe take the back cover off, and remove the connections to the left and right speakers, then connect a known good amp or receiver to each of the left and right speakers and see if the sound of the speakers is good first.

Then and only then, move to the amp part and like R. Totale said, spray contact cleaner into all the slide controls, etc. move them back and forth several times, and maybe spray again and repeat.
Then try with speakers again.

 

And be sure the unit is unplugged while bathing it in contact cleaner.

 

Honestly, you'd be better off getting -at least- a SEPARATE vintage receiver/source(s)/speakers from an audio manufacturer (something Zenith were NOT --- and, certainly, would not have been by the solid state era after 1965). "Allegro" was as low-end as the Panasonic speakers called "Thrusters". A tinny record changer with a ceramic pickup, an 8-track with (probably) tech borrowed from a car unit, and a compacted amp AIN'T gonna make anything sound satisfactorily at the end-of-the-day.
If you found(?), say, a 20wpc Sansui or Onkyo receiver on CL for $50 and...paired it with 1980s "Baby" Advent speakers and the most basic, manual Pioneer turntable (a PL-112): stuff like THAT would get you on a path of expectations MORE than anything the Zenith is going to prove capable of.

 

You are the first person I've read that says that these Zenith Allegros aren't worth it. The cartridge on the record player is a ceramic? By the way, the stereo crackles and has static even when I don't move any knobs. I don't know if that changes anything.

 

To add to timind's advice: when fooling around with electrical systems using 120V house power, BE CAREFUL. Even when unplugged there are components in them - particularly capacitors - that can store dangerous amounts of electricity for minutes or sometimes even days after the unit is turned off or unplugged.

Anyhoo.......

While not audiophile quality, IMO Zenith's Allegro speakers sound fine & are perfectly acceptable for non-critical music reproduction i.e. listening to the music and not the system. FYI: the most inaccurate portion of most consoles' sound spectrum is usually the lower bass, because very few consoles have their woofers operating in a proper enclosure.* So bass can be quite boomy or "loose"....though with the dance genre that can be a plus!

BTW usually the tweeters include a capacitor somewhere to filter out low bass to prevent the bass frequencies from damaging them. Those capacitors can dry out or simply age in ways that can cause the tweeters to sound soft/dull (or not work at all in extreme cases). While I've watched many Youtube videos concerning stereo consoles (and heard several in person), I'm not a restoration professional so can't help more than this.


* these days this is called an open-baffle system and such systems can sound very good....if built correctly.

 

I have heard a few similar type zenith Allegro consoles.

They for sure do not sound "Bad", but neither are they the pinnacle of Hi-fi sound.
You can expect Decent loudness and power but bass that is fairly heavy and boomy, and somewhat recessed upper mids and highs. Not a lot of detail, but a decent enough overall sound.

I had one years ago, and found that the built in receiver was the weakest link to good sound. The speakers were by far better. Hooking it up directly to a quality vintage Harman Kardon receiver, gave it a lot more punch and clarity and a more open and less boomy sound.

The built in amps or receiver, have an undefeatable "loudness" feature, that boosts the bass a good bit. They simply sound overly tubby and heavy bass sounding.

 

Can turning down the bass/loudness feature correct this boomy bass? And i will now be leaving the stereo unplugged for a few days now before opening the back!

 

No, you have to bleed the caps down. On a solid state unit they are only going to be at 35-70 volts so a zap isn't likely to be too dangerous. But there is enough current available the arc will damage things unless you use a resistor.

MOST 70s solid state Zenith receiver sections had very good RF performance.
The bass boost can be removed by changing a few component values. Probably in or around the tonestack.

The Allegro speakers that were round and fired upward into a circular cone thing were actually fairly good. If the drivers and crossover are in good shape the sound is , not "high end", but certainly as good as budget Radio Shack two ways of old.

 

After a lot of work and exploration, I managed to take the receiver out the cabinet. To better access the screws to get it out, I took out cardboard ventilation barrier, which didn't look too vital and necessary. I plan to use my Deoxit D5 and DeOxit Faderlube on both the pots on the receiver and other parts/connectors as per the Idiot's Guide to DeOxit (thanks again!). I'm also thinking about buying new handles and knobs for the front of the cabinet, as the handles currently on it are extremely 1970's, and not in a good way. The 8-track player's days are also numbered, as I plan to put a Bluetooth receiver there in its place. The issue with that will be trying to figure out how to fill the literal void when the bulky 8-track player is gone, as the Bluetooth receiver I'm looking at is quite small in comparison. I discovered that the turntable was unplugged when I took the back off the cabinet, so hopefully that's the only major reason why it wasn't working. I probably should hit it with some lube or something, and after snooping around numerous threads on here and other places, I'll be ordering replacement needles/cartridges from VM. Apparently, the Micro-touch 2gram thing was and is something special, so I'll be keeping the turntable in the cabinet after all. The speakers are pretty big at 15 inches. I also discovered that this is a Zenith Allegro Solid State D966. This is turning into a fun and exciting project. Also, I was surprised at how much 'JAPAN' and 'TAWAIN' on some of the parts. Who knew? Well, I didn't, anyhow.
Some questions:
Can I use DeOxit on the turntable switches, slides, and machinery?
What/how should I fill the space that will appear when I take the 8-track player out?
Is it possible to put a newer magnetic cartridge on the record player?