Embedded Files
Background
Background
The Sony TC-50, released in 1968, was designed as a battery operated handheld mono dictation recorder, but was discovered by NASA to be an ideal vehicle for the astronauts to record mission logs and play mixtapes for entertainment. It flew on most if not all Apollo missions (although I understand not down to the lunar surface in the Lunar Module). It was simple enough to operate with one hand, even while wearing a glove.
The cassettes were used for voice recordings related to the mission, but were pre-recorded before the flight with music chosen by the astronauts, and simply recorded over as the cassettes were needed. The Apollo mixtapes were made by music producer Mickey Kapp (obituary here), supposedly using his contacts in the music industry. More likely he made the mixtapes himself, copying records or commercial cassettes like the rest of us. Kapp had existing connections to the astronauts for years because they were fans of comedian Bill Dana and his famous José Jiménez character, who was on Kapp's label.
Although no official log of the astronaut song selections exists, the following have been repeatedly reported: Apollo 11's Neil Armstrong requested the 1947 album Music Out of the Moon by Harry Revel and performed by Les Baxter as well as Dvorak's New World Symphony. Buzz Aldrin selected Sinatra's Fly Me to the Moon, Glen Campbell's Galveston, and Barbara Streisand's People. Apollo 16's Ken Mattingly selected Berlioz's Symphonie Fantastique. Here's a link of Fly Me to the Moon being played from Apollo 10 over the radio to mission control.
This project to refurbish my TC-50 (which didn't play at all) was primarily to see and hear it working. It was never designed for quality music reproduction (in fact the sound is similar to a portable transistor radio of the era), but it is an interesting historical artifact.
Sony PR featuring the TC-50 and the NASA connection
Sony PR featuring the TC-50 and the NASA connection
Assuming that $119.50 price shown above was from 1969, that would be $1,048 today (Jan 2026).
photos of NASA flown TC-50s
photos of NASA flown TC-50s
The Apollo 10 TC-50 at the Houston Space Center. The display signage indicates the TC-50 was first flown on Apollo 10 - other sources indicate it was first used on Apollo 7.
From Apollo 12, this unit now at the Smithsonian. Note the NASA applied directions for use and velcro pads to hold the unit in place in zero G.
Here's the link to the Smithsonian webpage for this unit.
That same TC-50 from Apollo 12, with the tapes used in space. Not sure why the cassette labels were removed or covered up, but I'm guessing they were once labelled.
Notice the faux leather front of the TC-50 has been replaced with what appears to be duct tape on this unit.
TC-50 documentation
TC-50 documentation
Above: Schematic diagram. Note that there was a second version of the TC-50 (mostly PCB layout changes) starting with s/n 51,001 (changeover date unknown). This schematic is for the earlier version.
Above: The PCB layout and connections. That all looks so neat and clean. The reality is a bit different...
The TC-50 refurb
The TC-50 refurb
Above: the TC-50 with the case removed, showing that PCB, before any work. This is the foil side of the PCB, and the components are on the other side, inside the unit. The white motor is in the upper right, the battery compartment in the lower right, and the speaker on the left. Note the large number of jumper wires. I'll also point out that those wires are all soldered atop the PCB copper traces - not thru mounting holes as is typical today and was then. This makes for a messy setup and potential for shorts with adjacent tracks. NASA, however, deemed it suitable for manned spaceflight, so what do I know.
When the unit is first opened up, there's an adhesive plastic layer atop the PCB to prevent any shorts with the case.
This shows the speaker removed. The speaker is mounted with the magnet simply press-fit into that metal circular clamp.
In that speaker opening, you can also see a number of the electrolytic capacitors to be replaced, now pushing 60 years old.
Note they saved space by mounting the caps horizontally, under the speaker, as opposed to vertically as is typical for radial lead caps.
This is a view of the top/transport side of the unit without the case. Pressure roller to the top left, record/playback head top center.
Most of the case is simply screwed together and easily removed, but the front panel screws are located behind this adhesive faux leather piece which must be removed to disassemble the unit.
Since this unit has so many jumper wires connecting the PCB to itself and to the motor, heads, microphone, etc. I had to unsolder several of those jumpers to get access to the component side of the PCB to replace parts. Since there were so many connections, I decided to remove only those needed to tilt the PCB away from the transport side.
Here's another view of the transport mechanism under the PCB. You can see the rubber drive belt in the center and the motor on the right. The battery connections are in the front center.
Capacitor replacement underway here. The blue caps are new (Panasonic FC, 105 degree). The black caps are originals yet to be replaced.
Note the use of glue from the original assembly to hold some parts in place.
Capacitor technology has advanced quite a bit in the past 60 years, both in reliability as well as reduced component size. Here's a couple examples of the originals next to the new replacements.
The left photo shows the replacement 220uf/6.3v on the left and the original 200uf/6v on the right.
The right photo shows the original 100uf/6v on the left and the replacement 100uf/6.3v on the right.
The new parts aren't quite half the size of the originals, but are much smaller.
Here's a photo of all the 14 original caps which were replaced, along with the old belt.
Most of the caps were Nippon Chemi-Con and some were Rubycon.
All of these electrolytic caps measured FAR from spec. For example, the two 200uf caps measured 13.8uf and 9.5uf. The 500uf measured 34uf. A 100uf measured 35uf, and a 10uf measured 2.6uf.
Since the original belt was hardened and loose, I replaced it with a new belt from TurntableNeedles.com that fit perfectly.
One interesting note: the belt (both original and the replacement) has a square cross section.
The battery compartment had quite a bit of corrosion (on the left), but cleaned up much better after a soak in lemon juice (on the right).
The battery compartment door and label.
Note its labelled "Tapecorder" here, and referred to "Cassette-Corder" in the advertisement above.
Here's a rear view of the tiny meter that's used both as a level indicator for recording and as a battery strength indicator. Unfortunately it seems to be dead in my unit.
The battery pack with the cover.
Completed photos
Completed photos
Bonus section for Apollo afficiandos
Bonus section for Apollo afficiandos
The photos of the Sony TC-50 above were taken on a background of an Apollo Translunar/Transearth Trajectory Plotting chart. NASA produced a set of 3 maps/charts for each Apollo mission. You can occasionally see these charts in photos of Mission Control during the flights (an example below). Below is the Earth Orbit Chart, which showed each of the planned orbits for a specific launch date, including the TLI (Trans-Lunar Injection) burn which propelled the spacecraft out of earth orbit on its way to the moon. The Apollo 11 chart for orbit number 3 shown below:
This shows the Apollo 13 Earth Orbit Chart behind mission controllers at the splashdown of Apollo 13.
Next is the Translunar/Transearth Trajectory Plotting Chart which shows the position of the moon relative to the earth as the mission progresses.
Here is the Apollo 11 chart, but I used an Apollo 13 chart as a background for the Sony TC-50 photos above.
And third is the Lunar Orbit Chart, which shows photohraphic targets (for research and to plan for future missions) as well as the primary and backup landing sites. Again, this is Apollo 11:
Page updated
Google Sites
Report abuse