Black and White and Red-- LED channel display..!
 

Y'know those odd B&W portables that Zenith made for a little while in the 80's that had frequency-synthesized tuning and random-access channel keypads..? There have been a few threads here in the past that have mentioned them, but I don't think anyone has posted an actual picture of one. I used to encounter these things fairly regularly at yard sales and thrift stores and the like, but never actually bought one for whatever reason. [It seems like half the time these things have tuner/controller problems though.] Anyway, I hadn't seen one of them for probably 5 years or so... until today..! It's one of the 12" versions of this set (Zenith also made 19" models of this type as well) Yes, as shown in one of the photos, the price was a whopping 97 cents (marked down from $2.97). Found it at a Goodwill store in another city while on a little car trip today. It's a BT124W made in December 1983 in Zenith's Taiwan plant. It's pretty clean and in good condition except that the original telescoping antenna is gone (not just broken off, but completely removed..!). I might have a suitable replacement around somewheres. A bit more troubling though is the fact that the face of the CRT has a scratch that's deep enough to catch a fingernail on.

Couple of random odd things I noticed:
- The antenna input is just one pair of 300-ohm terminals as a combined VHF/UHF input. I'm sure that's because this set doesn't have the usual separate VHF and UHF tuners that other sets of this ilk normally have (the tuner itself just has one (75-ohm) input), but it does seem kinda weird on a 12" B&W portable. It just so happens I have the Zenith service manual for this set, and while there's no photo that shows the antenna terminal block, there is a line drawing which shows two pair of 300-ohm screw terminals. Also there's an actual photo of the back of a 19" version of this set, and it does have the usual two pair of screw terminals, so apparently at least that model had a VHF/UHF combiner built into the input balun.
- Zero points to Zenith for ease of disasembly on this thing. Removing and reinstalling the back from this set involves a lot more fuss than it should. There are only four screws to remove, but after removing the screw that holds the antenna terminal block/balun, you have to (a) lift and tilt the entire terminal block/balun assembly *out* from the back of the cabinet, (b) carefully rotate and manipulate the entire assembly in such a way that you can push it back *in* to the set through the mounting hole, and then (c) slide the line cord strain relief out of its mounting slot. *Then* you can remove the back of the cabinet. Reassembly requires the reverse of this procedure, including fishing the terminal block/balun from inside the set and pulling/manuvering it all the way back *out* through the hole just so you can push it back in position in its place on the the cabinet back. This all doesn't sound too bad, but it's made more difficult by the fact that there's not much slack in the coax line that goes to the tuner. Why they couldn't have had the terminal block mount against the 'inside' of the back cover like most other plastic-cased TV sets like this, I don't know. Granted, by the time this set was made, a 12" B&W TV would be pretty much considered "disposable" once it broke, but this was a top-of-the-line model that perhaps someone would have bothered having repaired.

I love it. Always wanted one of these rare-bird sets. it would almost complete my newer-Zenith collection. Great score and nice pic

Agreed.

Amazing. I love the idea of a B&W with digital tuning and/or OSD display, but I've never seen one. I can't think of any normal sized B&W sets sold here with anything other than click stop tuners.

The 14" color version of this set was used in various ads for the Tandy Color Computer, but the brand of the set was intentionally obscured in the ads. I never saw such a set and now I know why, Zenith was never sold here. I guess they used the US ads here for a while (later ads showed a 14" Philips set).

I have an Italian-made REX portable B/W set with a tube/transistor/IC hybrid chassis, remote control, digital synthesized tuning and nixie tubes for preset number/channel display... made in 1983!

I also have a Belgian 1986 Philips solid state B/W portable with on screen sliding bar tuning display.

Francesco

Tubes and nixies in a set made in 1983! Any chance of a picture?

I've seen quite a few B&W sets with digital tuning on various web sites including some current (or at least) recent production sets on those chinese wholesaler sites, but they were never sold here.

The last B&W sets I saw sold here (other than the little 5" portables) were 12" and 19" black cube sets sold in a really dodgy discount shop (dodgy because the shop made no mention whatsoever that the sets were B&W, displayed them switched off and had a no returns policy) in the early 90s.

They still had click stop tuners and it was the only give away looking at the sets from a distance that there was anything strange about them. I wonder how many of those sets they actually sold. I have never seen one since seeing them in that shop one day. I'd actually buy one now.

Couple of other semi-interesting things about this set:

- There are no video-related controls on the front or the side of this TV. Even the Black Level control (which Zenith used in place of "Brightness" controls on their TVs for a while) and contrast control are on the back. Aside from the channel selector, the only control on the front panel is the off-on-volume control. I don't think I've ever seen a 1980's 12" B&W portable that didn't at least have the brightness control-- if not the contrast and/or vertical hold control-- in some readily accessible location. On the 19" set(s) with this tuner, the Black Level control *is* on the front panel though.

- As some of you may already know, in most respects, the electronic tuner in this thing is about as no-frills as it could be. It's not cable-ready, there's no remote, and there's no channel skip or memory of any kind (it always resets to channel 2 when first powered on). However, it does have one kinda oddball feature, namely manually-adjustable fine-tuning. This is something I'd never have known without the service manual. Here's how it works. The direct-entry keypad requires you to always input two digits to select a channel, which eliminates the need for an "Enter" key. Also this means that no valid channel number entry starts with the digit "9", since the highest channel number you can tune is UHF channel 83, and channel 9 would be entered as "09" instead. So what happens if you try to enter a "9" as the first digit..? It goes into "fine tune" mode, that's what. When the tuner is in "fine tune" mode (denoted by showing a "-F" on the two-digit LED display), you can use the up/down channel keys to adjust the fine tuning on the current channel in discrete (but still crystal controlled) increments. The service manual says this is to allow you to improve tuning of sources that may have slightly off-frequency signals, like video games and home computers. That sounds kinda nice, doesn't it? Well, it's not as nice as it sounds though, because the tuner has no memory whatsoever for any of your "custom" fine-tune settings. If you adjust the fine-tuning on, say, channel 3, then switch to channel 4, and then go back to channel 3, guess what? You'll find that the tuning has been reset to its "normal" crystal-controlled frequency. ...And of course, powering the set off will also cause your custom "fine-tune" setting to get lost as well.

Funny you should say that. :) I don't think I've ever posted about this, but some time ago I got an RCA SecureView 12" B&W "prison" TV at a hamfest. [The seller had several of these he had bought in a lot, and he said they were from a prision. This was the only B&W one he had though (or at least had brought with him to the hamfest).] Anyway, as you can see, it's a modern B&W TV with OSD. It's also cable-ready. It doesn't have remote capability, but then it wouldn't if it was indeed used in jail cells. See the attached images.

Assuming those ads used the same photos they used in the USA, that was actually a Radio Shack -branded TV, and they did indeed offer those sets for sale at Radio Shack stores in the USA. I doubt they sold very many of them though; they weren't particularly competively priced, as I recall, and I don't remember them being on sale very often. I would guess those TVs were mostly there to provide a means of displaying/demonstrating the TRS-80 ColorComputers in the stores without having to resort to using a non-RS-private-label product to do so. Plus, it'd provide another nice "sellable" SKU. At that time, Radio Shack stores didn't carry TVs, so they wouldn't have had anything else to demo the Color Computer with. I don't know who made those Radio Shack TVs, but it wasn't Zenith. I'll admit that the model you're referring to does kinda resemble a color version of that 12" B&W Zenith with digital tuning though..!

I've seen those SecureView sets (both color and B&W) along with clear portable radio/cassettes in various prison documentaries I've seen, so they are definitely used in prison cells. The clear plastic cases are required to prevent inmates hiding contraband inside them (at least according to the documentary).

I googled SecureView last time these sets were discussed here and found quite a few posts on family-of-inmate type support boards bitching about the costs of these sets (supposedly $200+) and delays in getting them repaired.

I don't think our prisons have the same clear case requirement. The documentaries I've seen about our prison show inmates with ordinary TVs and radios in their cells. So I don't think I'll be seeing any (color or B&W) locally.

We did see translucent cases on everything from cheap 14" TVs, boomboxes and even irons (!) for a while after the first iMacs came out.

That's why I like to read this site! Thanks!

Here are some pics

The chassis has 5 tubes, one each in the horizontal oscillator, in the horizontal output and damper circuits (the HV rectifier is a solid state diode), in the vertical output and in the audio power amplifier

The rest of the circuitry is based on silicon transistors, with two ICs (for the IF and vertical oscillator/sync separator i think) and of course a few other ICs and a microcontroller in the electronic tuning/remote function module, the tuner itself is a varactor unit

The hybrid chassis in this 1983 portable dates back to the very early 70s, i also have a REX 23" wooden tabletop set from 1972 fitted with the same identical hybrid chassis but with a "car radio style" mechanical preset pushbutton tuner... apart from the tuner there are absolutely NO differences between the 1972 and 1983 chassis... other than MFG dates on components, which range between 8245 and 8304 in the 1983 set (the 1972 set also has a quality control sticker inside with a May 11, 1972 date written on it)

Note the slider pots for volume, brightness and contrast, they're quite quirky in that their maximum position is at the bottom and the minimum is at the top, on the side of the set are the 8 touch sensitive pads to control the electronic tuner (preset +/-, tuning +/-, fine tuning +/-, store/cancel) the preset memory is lost when the set is disconnected from the AC mains for more than about 30 seconds

Sadly this 1983 set has a really dim (almost black) picture, i'm not sure if i have a shot CRT or a faulty video circuit

...Yow! That's really an interesting mix of design choices..! A tube-hybrid set-- in 1983..! with electronic (varactor) tuning..! *and* Nixie tube channel indicators... *and* it's B&W... Amazing..!

Not only does it seem very surprising that anyone would have still been making tube-hybrid TVs as late at 1983, but the use of Nixies seems especially surprising-- LED readouts would have been a lot cheaper in 1983-- Nixie tubes were pretty expensive, and quickly lost favor in the 1970's after LEDs dramatically came down in price. I don't think any production USA-made TV ever had Nixie tubes, though I do have an old magazine (I think it may have been an issue of Radio-Electronics) with a picture of an RCA "concept" multi-screen TV that used Nixie-tube indicators for various functions.

Thanks Kiwick... Another reason I like this forum. Intersting stuff!

Some European TV makers (Grundig, Telefunken...) used nixie tube displays in their 70s sets, while Philips used a 7-segment nixie driven with a diode encoder circuit (a large PCB with tens of discrete diodes on it)

Althought nixies were obsolete in 1983, they were also dirt cheap as were the obsolete ICs needed to drive them...

For the same reason they dragged this (extremely reliable) early 70s hybrid chassis design well into the 80s...to cut on R&D costs, and back then, tubes made in Poland and Yugoslavia were still cheaper than power transistors and ICs anyway.

Keep in mind that in the early 80s B/W sets were still the way to go for most Italians, especially in poor rural areas.

Francesco

That really is one of the neatest things! When did that chassis go out of production? I have to wonder, if it were not for foreign competition, how long would have American companies hung on to designs like this?

I'm not sure, but the hybrid chassis was probably dropped in 1984, as all REX-Seleco B/W sets made after 1984 i've seen had a solid state chassis... and sucked

Their "all new" solid state chassis was quite unreliable and prone to fireworks, and had a ridicolous 0,8Watt audio output based on a tiny TBA820 chip, driving a small and nasty 16 ohm 3" Taiwanese speaker, and sounded like crap...

the older hybrid chassis instead was extremely reliable and had a juicy 3 Watt audio output from the PCL86 amplifier tube, driving a 4x6" Italian-made speaker... and sounded really nice