The Rheem Califone AV80 is one of the easiest electronic devices I’ve opened — a sign of the era in which it was made.
Many products from the mid-20th century were designed to be easily serviced, and the AV80 is no exception. Unlike a lot of modern equipment that is designed to discourage repair, the screws on this tape recorder were very easy to access and work a simple Phillips-style bit.
Obviously, you will need to remove the four D cell batteries to remove the rear/bottom cover. The removable assembly containing the input and output jacks is a nice touch, again a sign of servicability in mind. When removing the cover, it detaches. While replacing the cover, it simply slots into a grove.
Because of its size, most components are larger and easier to work with than I’d imagine you’d find with a Walkman or the pocket-sized Sony (non Walkman) mono recorder I previously had. There are no ribbon cables or flat-flex cables to snap. Like cassette recorders I’ve “tinkered” with in the past, there’s a lot of wires running everywhere.
Most of those wires lead connect to the printed circuit board. This board was clearly laid out by hand. This recorder predates even the use of integrated circuits, which even the Soundesign 7621 I also have uses. There are eight metallic Hitachi transistors. Two transformers, likely for audio amplification, are also present on the circuit board. There are covers or insulating tubes over the leads of many components, and the transistors slot into portions of the metal chassis (doubtful for heat dissipation, but possible).
There is one oversight in terms of servicability: All the wires are soldered to the circuit board. There are no connectors or plugs on the board, which was common for that period on equipment like this.
Next to the circuit board is the AC line power transformer, which converts the incoming 120 volts to 6 volts. There are also some diodes (of a design I’ve never seen before) nearby.
Next to the transformer is the motor. It attaches to the take-up reel and capstan reel through a rubber belt. A transport mechanism under the circuit board, sandwiched roughly the tape compartment, controls the tape — changing direction or speed. This mechanism also controls a switch on the circuit board that switches the machine from playback to record mode. (Obviously, flipping the switch will record over tapes.) There’s a separate belt that runs to the tape counter.
The Califone AV80 has a large (12cm) Sharp loudspeaker rated for 2 watts that gets quite loud. The Califone AV80 lacks an internal microphone. (More on that later.)
Attempt to diagnose
It wasn’t soon after opening the AV80 up that I determined I wasn’t the first person inside since it was manufactured 50 or so years ago.
First, there is a twist-tie — like you’d find on a modern loaf of bread — holding the wiring harness to the circuit board. Second, it appears some of the wiring has been tampered with.
The parts on the board all appear to be original. Although I will likely need to replace components on it eventually, specifically old capacitors, the machine’s electronics don’t to seem to be concerning… at least at the moment.
I am mostly interested in getting fast forward and rewind to work again, replacing the aging loose belt, and cleaning/lubricating everything necessary for trouble-free operation.
Unfortunately, I’m still learning about servicing it. There’s not a whole lot of information on the Califone AV80, except the electrical schematic and an exploded parts diagram. There’s no service guide, and that diagram isn’t detailed enough to provide an idea on how to effectively disassemble the machine without damaging it.
The aforementioned belt definitely has to go. I removed a tiny screw holding the capstan reel in place, which gave me just enough of a gap to remove and replace the belt. Unfortunately, I don’t know the size or how to acquire a replacement belt. I found a random rubber band at work, but — as I somewhat expected — it played really slow, and fast forward/rewind still didn’t work.
Rheem 3818 microphone
Another thing I know little about: The Rheem 3818 omnidirectional dynamic microphone I recently scored on eBay.
I originally thought this microphone would’ve been paired with the Califone AV80. However, upon more thought — and noticing the absence of the Califone name — I believe this microphone may not have been intended for use with Califone equipment. Rheem also manufactured public address systems, amplifiers and other audio equipment in the 50s-70s. The packaging uses the same Rheem logo found on the Kee Bass and Mark VII combo organs.
The microphone is basic and features a 1/4″ connector, another tip that leads me to believe it wasn’t meant for the AV80 or other Califone players. The Califone has a smaller (possibly 3.5mm?) jack for a microphone input, although there is a 1/4″ line-level input.
The included stand, however, leads me to believe that this microphone was designed for use with a dictation machine or tape recorder. It’s a small, flimsy plastic stand the microphone simply slots into. It looks like something you would find on an executive’s desk back in the day as they’re dictating something — like a letter for their secretary to write, or the next day’s to-do list — with their monaural Califone tape recorder.
I don’t have any blank tapes to test the microphone, or the Califone AV80’s recording capabilities.
Like the Califone AV80, the Rheem 3818 microphone was manufactured in Japan.
This post was written on a 1988 Macintosh SE “SuperSE” using Microsoft Word 4.0.