[Darren-UK]

Safety checks and powering up

We're all tempted to do it; obtain an old record player, radio or whatever and plug it in to see if it works whilst keeping our fingers crossed that all will be well. Temptation is one thing, doing it is another. Don't do it. Follow the basic checks as outlined below before plugging in.

Dampness

Any mains powered electrical equipment which has been exposed to damp must be thoroughly dried out before you apply power. This especially applies to equipment with an unknown history. For example, the old record player you found sitting on the grass at the car boot sale or the one you bought from an advertisement which stated "Found while clearing out grandad's garden shed".
Dampness will also kill a record player cartridge, crystal types in particular but more on that later.


Mains plug and lead

Mains leads, indeed any cable of the 'flex' type, consists of two or three cores which themselves comprise a number of fine wire strands. 'Flex' is an abbreviation for 'Flexible cable', as needed for domestic applicances of all types. For the purposes of this post we'll use the terms 'flex', 'core(s)' and 'strands'.

First of all, see what mains plug, if any, is fitted. If it's an old round-pin type this should tell you something, ie that the machine very probably hasn't seen the mains for decades. Such a plug is most likely to be unfused too. Even if a more modern 13A plug is fitted, don't be complacent. It might mean the machine has been used in recent times, but then again it's no guarantee of safety. Remember that 13A plugs have been around since the 1940's.

So if no, or a round pin, plug is fitted, obtain a good 13A plug and fit a 3A (Max) fuse. If a 13A plug is already fitted then open it up, check the fuse rating and replace if necessary. Then check the Live and Neutral cores terminate correctly and are secure. New 13A plugs are usually sold with a 13A fuse fitted. Unfortunately many people think this 13A fuse is fine to use with any applicance, not so. Please read on for more detailed information.

Now turn to the mains flex. Check it thoroughly along its length for splits, scuffs or any other damage. Pay attention, too, to the point where the flex enters the record player cabinet. Sometimes it passes through a little notch cut into the cabinet lid and damage can occur there. Remember that mains flexes, being external to the record player, are very prone to damage - damage that may not be evident at a glance.

Is the mains flex the now-obsolete single insulated type? If it is, you may care to replace it with modern double insulated type. Bear in mind the plug fuse is there to protect the flex, so ideally the flex should be of a higher rating than the plug fuse. For example, with a 3A fuse fitted the flex should be of higher rating, which will be 6A. Should a 6A flex not fit through the cabinet's cable entry, then you can fit 3A flex but with a 2A fuse in the mains plug. Plug fuses of below 3A rating are not commonly available on the High Street but can be obtained online. "Plug fuse", by the way, is the usual name for, well, a plug fuse. Don't just ask for 'a fuse' as there's numerous different types.



^ From time to time people can be confused by mains wiring colours, cable/lead/flex types and even how to wire a mains plug correctly. To assist, a few images of plugs and flexes are included. The double image above shows, at left, a plug fitted with an obsolete two-core, single insulated flex. These flexes consist of nothing more than two cores siamesed together. Despite the impression the image may give, the insulation of the cores and thus the whole flex is invariably of one colour.

There is an safety important issue concerning obsolete flex which is omni-coloured and this centres upon polarity. Indeed, it could apply to any type of flex. Normally the live side of the mains will connect to the input side of the mains switch (that's the record player's on/off switch). This means that when connected to the mains but the record player itself is switched off, the amplifier will be electrically isolated ('dead' if you like). However, sometimes either through error or, to cover any possible eventuality however unlikely it may be, through design, the on/off switch may be connected in the neutral side of the mains supply. This means, of course, that with the mains connected and the on/off switch off, the amplifier will be live. This obviously brings into question the power supply to the motor but this paragraph is adequate enough to warn of possible mains polarity problems. As will be repeated many times within this guide, if you've any uncertainties then please take no risks and ask in the forums.

Staying with the lefthand view above, we move to the plug itself. Note the 'V' shaped cable gripper; this type is designed to tighten its grip if the flex is for some reason pulled or placed under tension. Less common these days they are, however, very suitable for flat cross section mains flexes. Round section flex, especially if above 3A rating, can be difficult to insert. Note, too, the means of securing the cores of the flex. These consist of a knurled and slotted nut (screw on with fingers, tighten with screwdriver) with an integral washer. There is normally also one (often) or two (ought to be) other washers present, between or beneath which the cores are inserted before the nut is screwed on and tightened. The nuts and their studs have conventional righthand threads, therefore the bare strands of the cores should be twisted together and then looped around the threaded stud in a clockwise direction. Do not do it anticlockwise or the core will be forced out as you tighten the nut. Before refitting the plug lid, ensure no stray strands of wire are present which could project outside the assembled plug. This, of course, applies to any plug.

Moving now to the righthand view, we can see a more modern (but nonetheless now also obsolete in respect of wiring colours) flex fitted to a different type of plug. The flex depicted is still two-core but this time is double insulated; each core is insulated and they in turn are protected by a common outer insulating sleeve. Wiring (core) colours are now red (live) and black (neutral). Note the different and more familiar type of clamp, using a pair of screws for securing. The method of securing the cores to their respective plug pins is also the more familiar male screw type. These should be tightened so the cores are secure in the pins but with some slack between the pins and the clamp. Do not overtighten the screws as they can chew right through the wire strands and force you to start all over again.



^ This image is similar to that described in the immediately preceding paragraph. The difference being that the flex is now a three-core type with, of course, earth.



^ This image shows a modern two-core flex using the current, at the time of writing, wiring colours; brown (live) and blue (neutral).



^ This is the same as the previous image except that this time the flex is three-core and has the current green/yellow earth. Compare this to the earlier three-core arrangement.



^ This image shows something of an oddity which, nevertheless, you may well come across as it isn't exactly uncommon. Pay attention to the fact that the black core is live and the white core is neutral in this and only this case. Note the plug, in this instance the word 'green' is present in full to denote the earth connection.

On wiring mains plugs in general, if an earth core is present then this should be given more slack between pin and clamp than the live and neutral cores. This is to ensure that in the event of the flex being tugged to the point where it exits the plug, the earth will be the last connection to remain in situ.

One final point before we move on. Not many portable record players were earthed from new. In some cases this was for cheapness (ie the machine could've been earthed but it wasn't deemed essential) and in others it was for technical reasons, in particular AC/DC machines.* Therefore DO NOT attempt to earth any part of a record player without first seeking advice but, in a nutshell, if it wasn't earthed from new then do not attempt to earth it now. Some people think earthing the record deck is a good idea in an attempt to reduce hum. However, the danger is a fault (even in the wiring at or to your 13A sockets) causing the deck to become live. For that reason, even many decades ago some domestic appliances came with the warning "This appliance must not be earthed". The Hoover Constellation vacuum cleaner was one example which comes instantly to mind.

* For general interest, other reasons for non-earthing once existed. At one time in the dim and distant past not everybody had mains electricity in their homes. Of those that did, it might initially have been confined to lighting or lighting plus an absolute bare minimum of wall sockets. For this reason many appliances were connected via lighting bayonets and yes - this meant cables going up from a table or whatever to the ceiling. Special, sometimes switched, lighting bayonet sockets could be obtained for this purpose. None of these ceiling bayonets were earthed, being Bakelite or even wood, so earthing of appliances was at that time seen as pointless. When, in time, wall sockets became common, not all were three-pin; some were two-pin and hence still no earth.

In some areas DC mains existed. Often this was because power came from an existing, probably corporation owned, local power station built to supply trams and trolleybuses with DC power. This is the main, but not the only, reason why some radios and record players were built to be capable of running from AC or DC power (or in a few rare cases, DC power only) and thus were not earthed.


Basic short - and open - circuit checks

Now go grab your multimeter. The record player must be disconnected from the mains during the following checks.

Set your meter to a resistance range, ensure the on/off switch on the record player is off and connect the meter across the L/N pins of the mains plug. There should be no reading (ie zero if using a digital meter, infinity if using an analogue meter), if there is there's a short circuit somewhere between the mains plug and, or at, the on/off switch. If all is well, do the same again but with the record player switched on. There should now be a meter reading (meter needs to be set on a higher Ohms range for this) of a few hundred to a couple of thousand Ohms; the exact reading being dependant upon a number of factors. Don't worry if this reading begins to vary a little after a few seconds.

At this stage it's a wise idea to do a quick check on the electrical condition of the smoothing/reservoir capacitor (see post #10). Take the capacitor out of circuit (ie disconnect electrically) and switch your meter to its highest Ohms range. Connect the meter across the tags and watch the reading; you should get a low reading initially, climbing to a much higher reading. Now withdraw the meter probes and discharge the capacitor (meters on resistance ranges will charge the capacitor). Discharge by simply shunting a high value resistor across the tags or, if you don't have one, short the tags with a screwdriver and wait a couple of minutes. Note; DO NOT discharge a capacitor in this makeshift manner if the capacitor has been charged from the mains.

Having done this, grab your meter again and repeat the test. If you obtain the same, or very nearly the same, reading as you did first time around then the capacitor can be deemed serviceable.

Moving on, now connect one meter probe to an unpainted metal part of the deck, the stacking spindle is probably the most convenient. Connect the other probe to the L and N mains plug pins in turn; no reading should be obtained.

Few vintage record players were earthed as-built, although some may have had their decks earthed by a previous owner. If the mains plug has an earth connection, switch the record player on and check with your meter between the earth and live pins, then the earth and neutral pins. No reading should be obtained. Next connect your meter between a metal part of the deck and the earth pin of the mains plug (the record player may be on or off for this check). If the deck is earthed, the meter will show continuity. If this is not the case, then you'd be wise to find out where the earth is connected to. You're advised to create a forum thread in such an instance, giving as many details as possible, as your record player may have undergone a post-manufacture modification (perhaps in an attempt to reduce hum) which may or may not be safe.

Internal visual checks

You should now remove the deck complete with its wooden plinth. Usually this is located by four visible screws with cup washers, but sometimes access is by removal of the front grille. Before lifting, ensure the tonearm is secure on its resting post and remember that the deck can only be lifted to the extent the wiring allows. You will now have access to the power supply and amplifier.

First of all, look for any disconnected and/or damaged wiring. Next have a look at the smoothing can; this is a large electrolytic capacitor in an aluminium can (actually two or maybe three capacitors in the one can). Have a look at the end of the can where the terminals are located; is it bulging? is there a mould-like, or goo, substance oozing out anywhere? If any of these fault indications are present then replace the component and DO NOT apply power until you've done so. If faulty, this component can explode with some force.

If all appears visually OK so far, take a look at the other components. Is a mains transformer present (AC-only machines)? If there is, check for little piles of wax beneath or on the transformer. If present, other than in very minute quantities, there's likely a fault. If no mains transformer then there'll be a dropper resistor (AC/DC machines). Are all connections intact and set for the correct voltage? Is the resistor itself intact? On the subject of correct voltage, sometimes a voltage selector with a moveable plug is present; if there is then check it's set correctly and that the plug is secure.

All good so far? Right, now have a look at the other components. Look for broken and/or heavily burnt resistors. These are generally cylindrical components with coloured bands around them. Look for other capacitors; these take many forms but look in particular for any which are a yellowish colour and covered in a sticky, waxy, mess. If any are present then replace them. Other capacitors may have brown or black moulded cases; these may be ok, but by inference some may not be. Record players contain, in the main, very few components compared to a radio anyway.

Next, if this is a valved machine take a look at the valve(s). Is this glass intact? is the glass a milky colour? (if it is, the valve has had it), are the valves securely seated and, if more than one, in their correct sockets? If unsure of this, service data will tell you and there may also be a little label inside the cabinet telling you the valve(s) and correct position(s). It's wise, too, to remove the valve(s) and check the pins are clean and undamaged while you're there.

If all appears well, it's now time to get out your can of Servisol Super 10 switch cleaner. You know, the one you bought in anticipation of acquiring a record player. Switch cleaning is not, obviously, a safety check, but as you've just been doing an inspection inside the machine it's convenient to do this now before you replace the deck.

Attach the little tube to the can and simply spray into any convenient gap, hole or whatever in the switches. Next, operate the controls several times through their fullest extent. Take care not to let spray/fluid got onto or into anything other than the controls.

At this point it would appear convenient to mention internal fuses. Usually one, occasionally two, are sometimes found on the chassis/PCB of better quality machines. Some manufacturers, Pye for example, used a fuse contained inside a polarised plug. These fuses are glass encapsulated types and must be replaced according to current rating (usually quoted in milliamps - mA). Voltage is irrelevant. If you find a blown fuse, look at the glass; if clean the fuse has probably just died from old age. If the glass is blackened, however, this would indicate a serious fault somewhere, ie a short circuit. If a blackened fuse is what you're faced with then DO NOT simply replace the fuse and attempt to power up again. If unsure then ask in the forum, giving details of your particular machine.

The Lamp Limiter

So all seems well, you've replaced the deck and set the 'transit screws' so the deck is nice and bouncy and you're ready to plug in and, hopefully, listen to that Des O'Connor LP you found in a cupboard the other day. Hang on though, you've done some visual checks and some cold checks with your meter but you still can't guarantee the machine is ready to see full power because you don't know, for example, if you've missed a short circuit anywhere and/or if the electrolytic capacitors are fit for purpose.

So to power up your old, but unknown, record player, you ideally need a reduced power supply and a means by which any problems will be indicated to you. What is known as a 'lamp limiter' conveniently serves both purposes and a crude one can be made up with readily available items.

This device is, quite simply, a domestic 60W or 100W filament lightbulb in series with the mains supply to the record player, radio or whatever. Our main website has a very good section on lamp limiters, from which you can gain information on making one, how to use it and its benefits.

Lamp limiters have infinite value to those who undertake repairs and restorations with any regularity but, of course, have little practical value otherwise. Many people who arrive at the forums with an old record player just wish to get that item - and the item only - working, so construction of a lamp limiter as per the article linked to above might seem something of an overkill. If this is you, then you can make a simpler lamp limiter for one-off use. Grab an extension lead (aka "Trailing Socket") with a switched socket, bulb holder and a removable, ie non moulded, mains plug. Remove the plug, cut off about 3" of the lead and pull out the live core. Discard the rest of the offcut. Next slit an inch or so of the lead's outer insulation from the now plugless end and pull out the live core. Take care NOT to damage any core insulation. Connect the live core to one terminal of the bulb holder and to the other terminal connect the piece of live core retained a few moments ago. Refit the mains plug; live core from bulb holder to live plug terminal and neutral + earth connections from the extension lead to their respective plug terminals. Fit a 60W or 100W filament bulb and away we go.

At this point it's worth mentioning that when using a lamp limiter with a record player, the latter's motor may not start - or may start but have insufficent torque to drive the turntable when the mechanism is engaged. For electrolytic capacitor reforming purposes, some people prefer to start with a 40W bulb, then progress to a 60W and then a 100W (if you do this, remember bulbs will be hot so use a glove or a dry cloth). The record player motor probably won't start via a 40W bulb but should when a 60W bulb is inserted.

With your makeshift lamp limiter as described you will not, obviously, be able to eventually switch the bulb out of circuit. You'll have to remove the lamp limiter and then connect the record player directly to the mains socket when you're satisfied it's OK to do so. When using the lamp limiter, ensure that you have easy and quick access to the switched socket of the extension lead in case you need to disconnect power instantly and without having to cross the room to reach the wall socket.

Once done and if you doubt you'll need the lamp limiter again, just remove the mains plug, chop off the end of the lead from which you'd earlier pulled out the live core for connecting to the bulb holder and refit the plug. You now have a normal extension lead once again.

Stepping back now, once the record player has been running with no problems via the lamp limiter for, say, twenty minutes, it's a pretty sound bet that all is well for applying full power. Remember that with the lamp limiter in-circuit, your machine is on reduced power so full performance will not be possible.

Finally, initially, at least, you may be wise plugging in via an RCD as well as a lamp limiter. An RCD is a Residual Current Device, like what you'd use to plug in your power tools, electric lawnmower etc via.

Thanks go to Graham (Station X) for the images in this post.