Robot Restoration – Part 2

Project :

Posting of this project breakdown was delayed since I embarked on another restoration project of a later, 1970’s robot, this time mostly plastic with a metal drive and running on two D-Cell batteries that reflect some more functions compared to the Cragstan Yonezawa “Talking Robot”.

More complexity and a scary level of wiring and solders that need replacing has resulted in something equally complex to restore.

Both robots had been stored away in a black plastic bin-liner, before which they had been out of the sunlight in a bedroom cupboard that was badly affected by mildew. The mildew problem was sorted out by a builder but both robots had remained in the bin-liner for a long time and a combination of having little to do and being inspired by watching videos on the YouTube RobotHut channel prompted me to take them out and attempt a restoration since they had not really worked properly when I acquired them some time in the mid 1980’s from Gray’s Antiques in Bond St, London.

The Talking Robot is a tin plate robot toy which is relatively simple compared to the all-plastic robot I’m in the middle of restoring at the moment, having a friction drive in its’ base which you would push to make it move forward or backwards and its’ main feature is the talking mechanism inside, which is powered by a single D-Cell battery in the base of the toy, the weight of which also provides some stability to what is mostly a hollow tin shell. The arms are not powered in any way and simply swing freely on a metal rod that runs through the body.

The first stage was to clean off decades of grime and mildew from the exterior using a mild detergent and polishing after a spray of WD40, before trying to take it apart. One thing about this toy is that it had seen some action and also a rather poor attempt at restoration at some stage, and admittedly there are more pristine, mint condition robots of the same type out there – in its favour is its vintage, being an early example of the design, and the fact that it has been played with, though when I acquired it it had no accompanying box, which would add to its value.

Scratches had been painted out with red paint to match the existing paint work and there is some evidence of fading of the enamel paint.

I decided early on not to embark on a comprehensive restoration so that it would be “good as new” since this is a pointless task unless the toy is in reasonably good condition to begin with. It would be very difficult and unwise to try and do a new paint job for example, especially since the grille for the talking mechanism in the robots’ chest has some nice printed graphics, in good condition, and that would be hard to recreate by hand.

Tin toys of this age and type were held together by a series of metal tabs inserted into a slot or a slotted tab and then folded over, and additional parts like heads etc attach to the main body in the same way, so to separate the front and back shells of the body required bending back these tabs, a bit nerve-wracking since they can snap off, especially if someone had attempted to open the toy up before.

The earlier restoration had resulted in these tabs being distorted and scratched so I had to be extra careful.

Generally there are a series of tabs so if one breaks off then it’s not the end of the world. However, the talking mechanism is held in place by just two tabs on the outer body and attached to a slotted metal strip on the mechanism itself, inside the toy and if one of these tabs snaps off then the button that operates the mechanism on the front of the toy will get pushed too far in and the mechanism won’t work properly.

I think if I had not watched the video by RobotHut I wouldn’t have attempted to repair the talking mechanism, since it’s quite complex and it has more wear and tear than the example shown in the video, besides not working properly, or at all. There are also indications that an earlier attempt at restoring it had resulted in glue holding on parts, such as the blue plastic “diaphragm”, that should never have been glued together.

The “Talking” is achieved via a hard clear plastic disc that is essentially like a vinyl record – a metal needle on an arm follows grooves on the disc and the disc is made to spin via an elasticated belt driven by a small 1.5 volt motor.

Each button press triggers the motor and the needle moves through a series of pre-recorded vocal recordings of phrases randomly. When it works properly the needle should stop at the end of a phrase and either jump back to the start position or move to the next phrase, it’s impossible to predict.

The needle arm is in contact with the transparent blue plastic diaphragm and this amplifies the sound which comes out of the slots in the grille on the chest of the robot.

The part of the restoration that I had been dreading was soldering – more often than not, one reason for a toy not working properly is dry solder joints that inhibit conductivity. My initial attempts were pretty terrible until I watched a few videos on how to solder properly, and resulted in some minimal melting of the plastic casing in some areas. By the time I’d finished I was more confident about my soldering skills, which had improved by leaps and bounds.

The talking mechanism was by far the most frustrating aspect to this project and involved removing the 1.5 volt motor and completely dismantling it, applying WD40 and greasing the brushes inside, since it was not receiving enough power from a new battery to drive the disc belt as a result of accumulated grease and grime . I sprayed WD40 on any metal gears and spindles inside the main body of the toy to make sure that everything was free-moving but no matter what I did it, all I could get out of it was a squawk before the disc and motor stopped altogether.

From the point of view of soldering, the electrics are quite simple, with the two contacts of the 1.5 volt motor attached to the equivalent contacts in the battery box in the base. The button on the front of the robot is attached to a metal rod that pushes the disc forward to come into contact with the needle and in the process completes a circuit when two brass tabs inside the casing come into contact with a brass collar on the spindle that runs through the disc.

While the motor was running freely and the disc was spinning as it should, the disc itself was warped so the needle would ride the groove only intermittently, so breaking the electrical circuit and stopping the motor.

This was fixed by carefully flexing the hard plastic “record” against its brass spindle to correct the warping as much as possible – hairline cracks at the centre of the spindle from the previous restoration meant that this was risky to say the least but I managed to correct it just enough, along with adjusting a spring at one end of the disc spindle and the brass contact tabs, to keep the disc in contact with the needle.

Confident that the voice box was finally working, after thoroughly cleaning the “record” of accumulated grime and mildew – complicated by a glue spot from the earlier restoration that filled a small area of the grooves – I reinstalled the voice box and proceeded to reassemble the robot.

This is when the unthinkable occurred – one of the metal tabs that hold the voice box in place, snapped off.

Suddenly any sense of elation and achievement vanished and I was faced with trying to find a way to secure the voice box. Re-attaching the broken tab either with Super Glue or soldering failed and in any case these methods would never have allowed for the tab to be bent over to hold the metal strip in place without snapping off again.

Since the slotted tab in the other half of the tin shell was still intact I had a brainwave – maybe I could find a way to use that to insert a wire-tie to hold the two body parts together. This would mean drilling a tiny hole in the part that held the broken tab, something that any restoration would prefer to avoid since it then becomes a modification and may affect the toys’ value. However, without doing this the toy would be little more than a tin shell with a non-functioning voice-box inside it.

Luckily this worked and the two halves are held together using a small length of metal paperclip twisted to bring the body parts together securely on one side and also hold the voice-box in place. In spite of this, pushing the button on the front too hard could still result in the button going too far in and disappearing forever so to operate the voice-box only requires a gentle push.

The two black side panel strips effectively hide the repair of the missing tab so unless the toy is dismantled for any reason, outwardly it looks fine, and more importantly now has a fully functioning voice-box that cycles through various phrases as intended.

Of course it will never be as good as new but given it’s age and provenance, I felt a great sense of achievement and learnt a lot from attempting to repair it and hopefully add to its’ value.

A problem noted by other restorers of this robot and in general is that fact that repair doesn’t guarantee continued functionality over extended periods of time. Leaving the toy on a shelf or in storage for example can result in voice-boxes not working again or motors becoming sluggish after even a few months.

Why this is the case is anyone’s guess but it may have to do with factors like humidity affecting parts like the vinyl belt that drives the record or warping of the plastic record itself, as has been noted, in the case of the Yonezawa Talking Robot, besides the general age of the moving parts and wear and tear on metal and plastic gears etc, in the latter case which can split or crack due to stress and instability of the plastic itself.

The type of talking mechanism in this particular robot may have been unique to Yonezawa Talking Robot since these mechanisms were gradually replaced by a fully enclosed unit made mostly of plastic, with plastic gearing, of the type normally associated with vinyl “Talking Dolls” intended for girls – when opened up, they operate in essentially the same way with a plastic “record” and needle arm but are less durable than the more robust type described here.

Many smaller parts are replaceable however, something that I’ve discovered with the current restoration / repair where I had to source a replacement 1.5 volt motor and “grain of wheat” bulbs.

But of course each new project presents new challenges and the sense of achievement was a bit short-lived as the next project has proved to be more complex.

The Cragstan Yonezawa Talking Robot would have been released for both the Japanese and U.S / World markets, so the “record” would have been available with English and Japanese phrases – repairing it made me wonder who actually provided the voice, clearly American, and used across several other talking robots in various designs and still being used well into the 1980’s before the mechanical voice box was eventually replaced by a recording on a digital chip.

*Read Part #1 here.

Ravi Swami 2021