First equip yourself with some isopropyl alcohol or alternatively methylated spirit can be used, but does not evaporate so quickly. You will also need some strong cotton buds. I use the lint free industrial type mounted on a wooden stick. You can't really get enough force with the paper or plastic stick type. Do not leave the cotton buds or the isopropyl alcohol lying around, as they can both be dangerous if mishandled. Two more very useful items are a tiny dentist's mirror and a strong working light. I also often use a magnifying glass as well, to get a really clear view of the tiniest parts.
Disconnect the machine from mains electricity and set it flat on a table so that you can see the tape path easily. Remove the head cover of the machine. This is usually achieved by evenly pulling the cover upwards, but sometimes there are a couple of screws to be undone first. Some machines have two covers to give excellent access to the heads and guides. Be careful on older machines as plastic parts often become brittle with age.
Identify all the parts in the tape path. That is every part that the tape touches on its path through the machine. All these parts will need to be cleaned thoroughly with the cotton bud soaked in the isopropyl alcohol. Never use any metallic tools anywhere near the tape path. Pay attention to the guides where the tape touches first on it's journey from the supply spool. One of these may be a swinging pin and possibly a rotating guide. Be sure to remove every trace of contamination from these as a lot of oxide may be deposited on them. Pay particular attention to the upper and lower surfaces of the guides. Next to be cleaned will be the erase head. If this is not particularly clean the erase performance of the machine will be less than perfect.
The next head will be the record head which must be scrupulously clean to ensure full fidelity recording. If the cotton bud you are using has got dirty by now, change to a new one. Next head is the replay head. This is most critical for accurate playing of recordings. Don't be afraid to be quite vigorous when applying the cotton bud, as it is essential to remove all traces of dirt. This is where the magnifying glass, mirror and strong light will come in handy. Keep cleaning in an up and down and side to side motion until the cotton bud comes away clean. Some cheaper recorders have a combined record and replay head, so don't panic if you appear to have one missing. The advantage of having three heads is that you can listen to what you have recorded a fraction of a second later, confirming that no quality has been lost.
There may be other fixed or rotating guides depending on the type of machine. Just make sure they are all spotlessly clean and free to rotate. Don't disturb the adjustments on any of the heads or guides as this is beyond the scope of home maintenance. The next important parts for cleaning are the capstan shaft and the pinch roller. The capstan is a motor driven metal shaft which drives the tape through the machine at a constant speed by means of the rubber pinch roller which presses up to grip the tape and so pull it past the heads. The pinch roller may be very dirty on a neglected machine, so be sure to work your way all around it to remove all traces of residue. Rotate it by hand to achieve this. In extremely dirty cases it might be better to use a lint free cloth instead of a cotton bud as there may be too much dirt to be removed.
Lastly, there may be a further guide and possibly a swinging or fixed pin to attend to. These stabilise the tape before it passes to the take up reel and must also be very clean. If your recorder is still giving problems after all this effort, then it will require some expert attention from an experienced engineer. I recommend you use a tape head demagnetiser to degauss your machine after cleaning. This is good practice for regular use and ensures that noise levels are kept to an absolute minimum. Finally, replace the head cover and reconnect the power to your tape recorder. You will probably find that the quality of your machine has been restored. If the quality starts to be impaired again, especially when using old tapes, you will have to consider restoring your tapes and copying them to CD or some other modern format for the future.
The author, Nigel Hunt, has over 40 years experience with reel to reel tape recorders and is webmaster and proprietor of www.taperecorder.co.uk Reproduction of this article is permitted provided this statement and hyperlinks are reproduced in full and the article is not modified in any way.