The three jacks on the side of this computer that accept MIC, EAR and power plugs are of a somewhat flimsy construction that may become apparent after a few years of use (or earlier on rough usage) of the computer. The cure is fortunately rather simple for the mechanically/electronically handy user or technician.
The Fix
Step 1 – Take the bottom half of the case off (without removing the printed circuit board inside or the keyboard membrane plastic sheet at this time). There are 5 screws that must be removed from the bottom of the case. This is not as easy as it might seem as only 2 are visible. The other three are found under the rubber feet (rectangular strips glued on near the corners). These can be simply pulled off in order to remove the screws under them. Once the screws are completely removed, the bottom half of the plastic case should separate with only light prying. Any force indicates that the screws are not completely removed. See Fig. 1.
Step 2 – The printed circuit board is now secured to the top half of the plastic case by two screws. See where they are (upper to mid-left near the RAM pack opening and near the centre, more towards the middle of the case, typically). For reassembly, note where they came from, with a soft pen, say). The printed circuit board must be moved up and away from the top half of the case about one or two inches only (so as not to disconnect or damage the fragile keyboard matrix/membrane plastic from the connector on the board). See Fig. 2.
Step 3 – Holding the printed circuit board so that one can see the three little plastic boxes that house the jacks, any prongs that are bent too far up and out, may be carefully pushed back into position with a small screwdriver or toothpick. Several pushes back may be necessary until the springiness is overcome in its attempt to reposition the prong outwards. Now test the jacks with the cable for the cassette recorder (no power applied) for mechanical fit.
Step 4 – Now you are ready to reassemble the computer making sure that the screws for the printed circuit board are not inserted in the holes meant for the screws that hold the outside bottom shell of the case. If you put one or both of these screws in the wrong place, the screws will not go in when you try to screw the back on again and all the screws on the outside will have to be removed and the bottom taken off again to find the source of the problem. Do not disconnect the little metal bar or whatever; that ground contact with the metallic paint inside the case that provides some measure of protection from RFI for the T.V. etc. on VHF models of the computer.
Step 5 – Once the printed circuit board is secured inside the case with its two screws and the bottom of the case secured with its five screws and the little rubber feet or runners stuck back on, you are ready to test the computer to see if the original problem is fixed (and no new ones added).
Note that a loose power jack into the computer can also cause the save/load crashes and some users have either tightened up that jack too, or replaced it with hardwiring the power supply wire to the P.C.B. and adding some safety device like a switch on the power line or pilot light (standard LED and 1/2 watt, 1K ohm for example) to make sure it is not left on.