front panel restoration
To carry out this repair, we must lay down their components attached on the front panel. First, the var-caps. we unscrew the screw locking pinion gear on the command axis: The button and the axis can then exit through the front panel. It is necessary to remove the pinion We do in the same way with each rheostat axis. If the axes are seized, it is necessary to use unseizing agent to prevent breaking the button. If we must use pliers, it is necessary to interpose thick fabric: The needles dials varcaps are to be removed; for this, we must remove the nut-eyed: These needles appear to come from an old clock: When the 4 axes are off, it remains 2 large screws, between rheostats, that hold the wooden plate; they must be unscrewed. The plate is then released And then we discover varcaps and rheostats fittings : just unscrew the 3 screw of each varcap for deposit. Then the 2 bolts of rheostats. The two variable capacitors released: The rehabilitation involves polishing the steel wool axes, and to lubricate them. The sliders of rheostats will also be polished, as well as the center contact on the axis. For the varcaps, needless to desassemble them: it is necessary to lubricate the axes and operate them by hand until they rotate freely. The front wheel covers, as well as the varcaps needles, screws and sliders of rheostats are pickled in the diluted acid, and then scoured. Finally, they are polished with steel wool. Incoming state: State after cleaning: The wood can be cleaned (steel wool) and varnished or waxed. The oscillator coils plate must be deposited for removing dust and checking it. Each coil resistance is about 1.5 ohm (in fact, there are 4 coils, 2 by 2 assembled) We must also inspect rheostats: they are crossed by significant currents and the slightest bad contact would be detrimental to the proper functioning of the radio. It is best to deposite them from the front plate, but if everything appears normal, we can be content to use very thin sandpaper on the turning contact (the central puck) and on the track (resistor winding thickness) For me, the rheostat "K" (the one that compensates the reduction of heating-battery voltage during discharge) is out: Indeed, when I have tried to unsolder the last wire of power cord, I found that riveting was broken! This was hardly visible before oscillator coils deposit, if I had not done so, I would not have had heating ... I made this riveting by using a 3 mm(diameter) bolt. The best thing is to tear down the winding of the basement. The screw is a little grinded so, it does not exceed. Just to fix the rheostat on the front panel. The capacitor CB needs to be changed. Its value is 2µF. Initially, it is not polarized, but we can use an polarized one. A voltage of 160V is sufficient. I prefer to use 2 caps 1 µF/250V not polarized ... When the capacitor is removed, it must be emptied. Not many methods: the drill with a 10 mm drill. We make several holes and with pliers, we remove chips. It is long, tedious and dirty. When the box is empty, we install the new capacitor with 2 wires. And we all drown (I used paraffin recovered from the catacomb) Simply connect the 2 wires to the terminal And fix the cap on the front panel. Well, the front panel is revised; reassembly can begin!
We need to start fixing the dials on the wooden plate: I changed the 8 screws that were really oxidized. Instead of spending time to renovate them, I have prefered using new brass screws. They are a little longer, I had to grind them when being in place, just at the edge of the nuts. Then the wood front plate is attached to the metal frame with 4 rounded heads screws: Then, the axes is reinstalled the varcaps needles too. Do not forget the rheostats needs that are washers wich have to be put under the buttons. The catacomb shock absorbers were completely dry: I have decided to rebuild new ones. Here is how I have done: A) I first cut 2 shapes in cardboard to make boxes whose dimensions are 44x28x26 And 2 internal walls approximately 25x21 dimensions. B) when boxes are assembled, partitions are glued to mid-length, on the bottom. C) I cast silicone rubber that I dyed red. D) then, we can unmould: E) the wall remains in rubber, but it is easy to remove it: Below are the new blocks installed in their place: The slot is closed, it is normal, I expected slightly lower dimensions for all to be held. These are the legs of catacomb that will come into these slots. The catacomb is fixed with 2 semicircles. Initially, these pieces were each in a different direction, but during reassembly, I preferred to put all of them oriented in the same direction:
Now I can rewire the catacomb. The colored marks posed during dismantling are very useful ... When the connections are screwed, the power cord must be shrinked, as well as the 2-wire link to CB cap: Here are some pictures of the revised chassis. View from below: To the right: To the left: Seen from above: other views: Front view:
substitutes for 99's...