An unexpected find made me happy a friend the other day. He brought a miracle apparatus of Soviet times. Before that, I had seen him many times in advertisements, but had never met him live.
In the USSR, there was a special category of radio goods: children's. You could criticize them as much as you like for their modest design, but the price is two times lower than the counterpart from the "adult" category outweighed everything. More than a dozen brands of children's tape recorders were produced. Basically, these were tape players - without a recording function. In principle, the kids did not need it: the cassettes were recorded on stationary decks with a higher quality.
Owners of children's tape recorders very quickly began to pull on "modernization": they installed more powerful speakers and amplifiers, added homemade radios, turning them into radio tape recorders. And adults, through a simple alteration, turned them into a convenient car tape recorder.
Our "time capsule", children's tape recorder "Junior" started production in 1989.
They were produced at the Ryazan Instrument Plant, along with the famous line of tape recorders "Rus": models 205, 207, 309, 310.
Usually, children's tape recorders did not like a good tape drive mechanism, a toy. I was very surprised to read an advertisement from those years that in "Junior" LPM is applied from a tape recorder "Rus-207". On a toy tape recorder, LPM of the second class is practically from the realm of fantasy.
Having examined the case from all sides "Junior" I was surprised to find that the seals were in place. However, when examined with an armed eye, it turned out that this is ordinary dirt that got into the niches of the housing attachment and dried out. This is the kind of "careful" treatment that Soviet tape recorders had to withstand and continue to delight the owners with good music.
An autopsy of the tape recorder showed that in addition to the standard problem with belts and rubber rollers, rust worked thoroughly in the CVL.
LPM is really very similar to "Rus-207", but in a truncated version: one flywheel and the mechanics of rewinding are removed. So the parameters of the "Junior" LPM are far from being of the second class.
The electronic board is very simple: a preamplifier based on a pair of transistors and an ULF on a 174 UN7 microcircuit. For some reason, the connection of the radiator of the microcircuit with the common bus is made with a separate jumper. It seems that the place for the conductors on the board is simply heaps of.
Since 1991, they began to produce a new model "Junior-M", which already had a recording function.
As you can see, an operation mode switch has been added to the board, and the circuit has become more complicated.
I looked for a diagram on the Internet, but I could not find something. There are no questions about UN7, but it would be interesting to look at the diagram of the rest of the part.
Look back in TABLE OF CONTENTS- there are many interesting articles, we have something pleasant to remember.