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Fault Finding

With the recent surge of the 'do-it-yourself' type of enthusiast it has become apparent, from the many phone calls received, that some people find fault finding on a juke box confusing - it is actually just a question Of methodically working through the different systems present in a juke box. A jukebox has three basic systems :
Making a selection,
Playing the selection,
and The Sound.

The sound can always wait until you have the mechanics working correctly. Best thing to do is disable the amplifier before you switch on and then you will have oneless thing to worry about going up in smoke.

It is also worth considering having your amplifier rebuilt by an expert, like myself, particularly valve types which are now of an age that they could really do with a complete job and not just a couple of caps and the odd resistor changed.

How to disable your amplifier depends to some extent on the make/model. The easiest way is to simply remove the H.T. rectifier valve. You can, on some models, simply pull the supply lead to the amplifier, but this can sometimes lead to a problem if the amp is also supplying the low voltage to the mechanism ! Thought does have to be given - get a service manual it should help, even if it is only when you phone someone for a bit of F.F.A. (free friendly advice) !

So with the amplifier not worrying you it is now time to look at the mechanism. First you have to understand that the machine is designed to take money. You are not allowed to operate the machine without establishing A ‘credit’ and this is done by inserting a coin.

The coin is detected by the coin mechanism switches and sends an electrical pulse to the credit unit which can also be called credit accumulator or pricing unit depending on the manufacturer.

The credit unit will not allow you to make a selection if it has no credits established 'No pay - No play' So it is an important consideration when trying to make your selection - you can put most machines on to free play or manually clock up a credit or two - usually done by locating the add coil (or CREDIT SWITCH)and manually operating it.

This done then you may try to select. If not satisfactory then check that the mechanism can play the selection or as it is often referred to - 'read-out'. To check this you must find a way of starting the mechanism without the pushbuttons being involved.

If this can be achieved then you must also find a way of faking a selection. In Wurlitzer both operations happen simultaneously : each selector pin represents the side of a record and if one of them is made to 'pop-up' this also starts the mechanism motor to turn to that pin.

Pre-Tormat Seeburgs have a similar system but with a start switch separate - Tormat type selectors have been dealt with in previous newsletters.

RockOla generally have a start switch arrangement that has to be activated before the machine will scan to look for the selector pin and our dear old AMi also has its' scan control assembly in most models for exactly the same reason.

By establishing that the machine will 'read' the selection and hopefully carry on to the play position you will have demonstrated that at least half the machine works.

You can then concentrate on making the selections? or 'writing' them in via the button bank. I hope that you can appreciate how confusing it could be if you do not establish what is or is not working as most of the time we are looking at the symptoms of the fault(s) rather than at the fault itself.

By establishing that the machine will 'read' the selection and hopefully carry on to the play position you will have demonstrated that at least half the machine works. You can then concentrate on making the selections – or ‘writing' them in via the button bank.

I hope that you can appreciate how confusing it could be if you do not establish what is or is not working as most of the time we are looking at the symptoms of the fault(s) rather than at the fault itself.

All juke boxes operate in this way although the actual hardware is different between manufacturers. Before you give up and phone for advice : Get your self a service manual !(available from The JukeboxMan).

Try to find which parts are working by some very basic work. If you can't get your head round it get someone in who can - you know it makes sense.

Fault Finding - Seeburg
Seeburg did things a little differently to others and so the first thing
that you will need is a service manual for your model (available from The JukeBox Man) and then some spare time, alot of patience and ignore the phone !

One fault that often occurs in a Seeburg is that the carriage scans twice and stops without playing the record that you selected. As always you must check that all plugs are seated correctly and all valves (if there are any) are lit up (the 5u4g only lights when the mechanism is scanning). Check that there's a purple glow in both type OA2 valves: no glow can be caused by a weak 6X4 valve. If no trouble is found and the service switch is in the play position, make sure that the machine has several credits logged in and proceed as follows :
On the back door of your (50's) machine are two chassis (not KD) . The Left hand is the Tormat Selector Unit (T.S.U.) and the right hand the amplifier. For exact locations and positions of valves etc.you should refer to the service manual for your particular model  of machine. On some models about halfway down the T.S.U. is a long thin cover which,when removed, reveals the "test terminals" lettered A-H - usually situated near the "pulse amplifier".
Remove the terminal cover as you will need to use these terminals to help you establish the location of the fault.
Remove the memory unit output plug from the pulse amp. then connect one end of a 'jumper' wire to test terminal C leaving the other end free. Make any selection and ,while the mechanism is scanning,  momentarily connect the free end of the lead to the input of the pulse amp, making sure that you connect with the centre of the socket.
The mechanism should immediately trip to play. If the mechanism does not trip to play this could mean that you either have : 1. A trip fault or 2. A pulse amp fault.
The obvious way to test for this is to replace the 2050 trip valve and/or the pulse amp 12AX7.They are the two most consistent offenders although any of their associated circuitry could be at fault.
One neglected capacitor by the would be restorer is the 0.05mfd inside the pulse amp.  - worth changing!
However if the mechanism did trip, reject the record and let the mechanism scan to a standstill. Remove the jumper wire from C and carry out the following :
Momentarily connect the tip of the memory unit output plug to the positive of a good 1.5 volt battery with the case of the battery held against the corner of the pulse amp (i.e. negative to earth). This simulates making all selections on the tormat.
Replace the memory unit plug into the pulse amp input and make any record selection. When the selection is made,regardless of number/letter, the mechanism should immediately trip and play. If so , reject the record and check if the next record plays - the battery has effectively made every selection and all records could be played if desired. If the mechanism trips on at least two records pull out the memory unit input plug, reject that record and allow the mechanism to scan and stop before replacing the plug again. You now know that the 2050 trip is working , the pulse amp and both OA2 valves with the 6X4 are also OK.

Consulting the manual for your machine will tell you the position of the "Universal Pricing Unit" this is what Seeburg call their credit unit. Remove its' cover to check that the relays and trigger switches in it are clean and their contacts are functioning correctly. It is also worth checking the relays and contacts in the Stepper unit if there is one. The relays known as timing relays are worth a check as just one contact not making on these can also cause a 'write in' fault.

Blinkin' Dinkin'

There comes a time in every jukebox owners life when you are faced with the necessity to dink.Quite simply dinking is the process of enlarging the hole in the middle of the record so that it can be played in a jukebox. Why is this necessary ? In the U.S.A they have a slightly different system to us when it comes to playing vinyl.Originally when the first 45rpm records were produced they had a large hole made in the centre to designate the speed as 45.The 12 inch albums had a small hole for 33.The early record decks that plugged into your radio were made to promote the large hole and were made to take a stack of the 7inch discs and auto-changed them. Of course the 45rpm jukeboxes were all made to accommodate this system being as they were,made in America.

However and for whatever reasons, we here in the UK had a system with all solid centres so that we could play any speed on our Dansettes!
Records did have pop-out centres making dinking redundant but with reissues and anything past the sixties and you will probably have solid centres.So how do you do it ? I am sure that there are many ways but here are just one or two I have heard about.
Well, you could draw a circle with your kid's school compass, then get out your Black and Decker fret saw, I'm sure we've all seen a few records done in that or similar ways. The problem is that the hole must be dead centre unless you are so tuneless that wow and flutter (variations in speed caused by the non central spinning disc) don't matter. A professional dinking tool is something to search for. Back in the 'old' days such machines were very common as most record stores had one ,tucked away under the counter, and of course in latter years didn't realise what they had and binned it ! They are easy and fast to operate so keep looking - its worth it.

A device appeared not so long ago which can only be described as a scriber and was probably inspired by the kids compass routine. However this has been refined so that the machined end of the tool fits into the centre of the record and the arm sticking out ,which is sharpened,is then pressed into the plastic and turned eventually cutting through the record.Pete assures me the process is speeded up if you attack the record from both sides and that it is important to keep the tool at right angles to the record, particularly at the beginning of the process.If the cut is off-centre to start with it's impossible to get back onto an accurate path leaving yet another spoilt record.The other drawback is physical : do a dozen of these in one evening and you'll feel decidedly limp-wristed the next day !

Next we have the Q-max cutter which is a precision made tool for cutting holes in metal etc so a little bit of plastic does not bother it. Consisting of two parts connected by a threaded bolt.The action is simple -
put the bolt through the centre of the record with one half of the cutter
on one side of the disc and screw on the other half from the other side...but wait a minute ... that sounds easy - Well yes in theory it is..

However, the centre bolt is too wide to pass through the record hole which means that you have to start by reaming the hol so its just big enough. You can use a reamer or careful use of a countersink bit in your drill or (do as our Nursie does) sharpen up the end of the Allen key that you operate the cutter with ; using that as the reamer as it is the correct size. It is essential that the centre hole is not made oversize otherwise you will still not be able to dink centrally. Here at The Jukebox Man I now supply the Q-max with appropriate Alan key sharpened to a point - See here.

Next step after enlarging the centre hole (very slightly ) is to keep one half on the bolt on one side of the record and pass the bolt through the plastic.Then you thread the cutter on to the bolt that sticks through the centre.Using the other end of the Alan key you can now tighten the two halves together.It is important to keep going even though you may hear some alarming clicks etc.. The record should now have a large hole centre ready to be played on your juke box. What goes wrong ?

Well I suppose getting the hole too big is number one and number two is certainly that when dinking records without a paper label they tend to break - even with the professional tool. Now this has always annoyed and baffled me but, thanks to a customer, I have a pretty good solution. I used to tell people to warm the cutter up if you were going to do those type of records were the printing is direct on to the plastic and then maybe there would not be so many breakages however just recently a customer came to me and said that he had quite a high success rate when dinking these type of records if he stuck masking tape across the centre first (on both sides) and then dinked them ... O yeah ! ....WELL .... I have tried it and all I can say is - WOW !

 

FREE Play!

'Free play' what a phrase, it just has that certain ring about it - I love it. What is for free in this life ? Well I reckon playing your own juke in your own home should be. I know a lot will disagree, especially if you have just bought or are thinking of buying a jukebox. Old hands at the game will already be nodding sagely as they know what is coming next. Yes it is nice to 'drop-the-coin-right-into-the-slot' but after the coin has 'hung-up' on you a few times that really gets a little tedious, especially if you are having a party: having to pull the juke out of the corner - take the backs off and remove the slug rejector to enable you to clear the jammed coin with the assistance of several drunken bums chief of whom being yourself !
'Free Play' is the answer ! So what is 'Free Play' ?

Free Play - is a way of 'fixing' the credit unit so that it is fooled into thinking that coins have been deposited.

On the early models of machines such as Wurlitzer 1015 and 1100 it is usual to put a jumper plug in place of the coin grinder unit plug as these were relatively simple circuits which can be easily rigged with no trouble at all - eg for a Wurlitzer model 1015: link pins 1 to 8 and then pins 5 to 6 on a dummy plug for the model 1100 simply link pins 1 to 3. Later makes/models present different problems.

Ami in the 1950's and some 60's models that used similar credit units are, like most jukes, easy to render to free play. Assuming that your credit unit is functioning - establish credit. Then locate the subtract coil - that's  easy as it will be the coil that actuates when you make a selection as it removes a credit. Next remove the supply to that coil : this can be done by cutting one of its wires and taping up the bare ends or you could add a simple on/off switch. By including a switch in the circuit you can then , at the flick of the switch, convert from free play back to the credits being taken off and back to dropping the coins.
RockOla jukes are not so easy !

The action of the subtract coil is integral to the selection pulse being switched through to the pin banks. This is done when the subtract coil actuates, the arm that moves down to remove a credit off the credit wheel also closes a set of leaf switches which send the pulse on its way. One way to put this type of credit unit on free play is to carefully remove the end piece of that arm which is also spring loaded. The arm will then still actuate but not remove any credits.

Of course it is essential that you keep those small pieces in a bag inside your juke as they would be difficult to rplace if lost. You could also get around the same problem by jamming the credit wheel assembly actuator : this would be the same effect as if the coin switch was actuated but without the smoke and fuses blowing.

Wurlitzers using their'playrack'system are simple. The spring that pulls the black credit wheel back to the key switch when the subtract coil fires is easily fitted the opposite way and will keep the wheel from opening the switch and so on free play Lastly Seeburgs : it is not recommended that you mess around with the pricing units trying to put them on free play as this usually leads to excessive heat in the latch coil quite often leading to a small fire. There  are devices claiming to be free play units but actually all they do is save the latch solenoid from burning out. This can be done just by disconnecting it and all his means is that you will have to hold the letter and the number button down together at the same timewhen selecting.

Rubbers!

Just as important as loudspeaker phasing and just as overlooked are the parts made out of rubber in your jukebox.Parts made from rubber usually have a key role in the function of the juke.
It is essential that these parts are in good condition and are not allowed to become hard,brittle,perished or misshapen in any way as this can seriously effect your jukes performance. Age and bad storage contribute to the rubber parts"going off" .In certain positions it is often the constant contamination of lubricants that also contribute to the rubbers failure.

SEEBURG
Rumble in the"selectomatic"mechanism can often be pinpointed to the rubber mount discs top and bottom of the motor and/or the motor coupling between the motor shaft and the Mechanism mechanism drive worm.These need to be checked to make sure that they are still resilient or motor noise will be easily transmitted to the pick-up if they have hardened.

WURLITZER
Phono motor drive belts are obvious things to check but what about the two rubber mounts holding the motor to the mechanism AND the two grommets cushioning the motor bracket from the mechanism...Usually "rock hard" by now and giving absolutely no isolation,for the pick-up,from the motor vibration. Result quite a racket reproduced through the speakers and very noticeable on quiet records and lead in- and lead out grooves.

ROCKOLA and AMI
Phono motor mounts MUST be pliable to maintain their anti-vibration qualities and the correct height for the motor spindle so the idler wheel is positioned correctly.The idler wheel should not be"rock hard" as it too must absorb motor noise ,not transmit it !
The wheel can also be the source of,an often heard rhythmic knocking/bumping noise that emanates from the speakers,in the background of the record that you are playing. This noise is due to an indentation on the edge of the wheel in the rubber:usually caused by long term storage with the turntable in place - the motor spindle digging in to the rubber surface. As the turntable revolves the bump occurs every -time the blemish goes over the motor spindle. On earlier RockOlas the tone arm pivots at the rear supported by two rubber grommets. This pair of grommets often deteriorate to the point of disintegration causing inconsistent record set-down any where on the record.
The only real cure when rubber parts are affected is to replace them.

Real Wood Finishes

A contribution from Norman Macrae (subscriber 182 to Jukebox News)

Being able to recreate a wood finish (wood graining or scumbling) is quite useful in the restoration of some jukeboxes. Some years ago, I came across someone who recreated these finishes and he did some Seeburg M110Cs and an M100A for me - superb jobs. Unfortunately this technique came very much back into fashion fairly recently with the result that my contact got very busy, his prices increased and I don't think he was really interested in my mundane cabinets any longer.The finishes he did for me were based on colour photographs etc of the machines and he always told me that they were really straight forward to do because there were no fiddley bits (no knots in the wood etc - which is more complicated for the novice to recreate). Last year, I was restoring a Seeburg KD200. The finish on the cabinet sides was really dreadful, it was painted off-white - a sort of creamy yellow /brown, if you can imagine that; durable but horrible and it had to go!.

During a visit to my local B&Q, I spotted a special offer on a wood graining kit,containing base coat, top coat, comb device to create the grain and an instruction leaflet - exactly what was required! So the time had come, the KD sides were to be tackled and I was to make my first attempt at wood graining. I selected the wood finish I considered most suitable and for about £10, I was in business.

The way that this finish is applied is to lay down a base coat and let it dry; then lay down thetop coat and while it is still wet, create the grain by drawing the comb through the top coat to expose the base coat. Or put more simply - follow the instructions in the kit. I spent some time practising on a piece of white hard board to make sure that I could get the style of finish that I wanted. In the end I used a stiff paintbrush to create the graining; this gave a finer grain which was more similar to the original. After the initial practice runs, I then did a bit of practice on the machine itself. I actually ended up using the horrible creamy yellow / brown as the base coat (I decided it looked best!), I just sanded it down a bit first.

The secret, I think, is to practice until you are confident that you have got the method right and the grain pattern is exactly what you want. Don't worry if at first you don't succeed , just wipe off your efforts and try again. Because of the lack of fiddley bits, it was just a case of drawing the brush from top to bottom moving from left to right with adjacent stokes across the KD side panel creating the grain progressively until the complete side was done.

When you've completed the job and you're happy with the result, let the paint dry and then seal the finish with some clear varnish. I was well pleased with my first effort, it really was straightforward and the necessary paints etc are now readily available in all do-it-youself shops. I believe that B&Q even do demonstrations, not that I've attended any of course - after all I have just awarded myself the qualification of wood grainer (lower grade).

 

Leaf Switches

Having had to explain to customers on more than half a dozen occasions how to adjust 'leaf switches' I thought that I would share it with all of you and maybe not get asked quite so many times in the future.
Leaf switches are in most of the older models of juke box. They are designed to be accessible for cleaning and maintenance. Basically consisting of thin strips of sprung copper with a contact fixed to one end and held at the other in strips of insulated material. The switches can be built up in to many different configurations to provide multiple switching actions such as the Seeburg reversing switch shown below -

Many of this type are actuated by a lever/spring arrangement with the different sections of switches movement coordinated by the end plate.This will ensure all switch sections change simultaneously. This type of switch was used by not only Seeburg but Wurlitzer, AMi and RockOla and it is not unknown for the switches of this type to loose their spring device that snaps the end plate over thus loosing the switching action and even that end plate to be missing.
Cleaning contacts is another of the restorers "mysteries" - or rather - how to do it properly is. "Flooding" the contacts with switch cleaner isn't really going to help on old tarnished contacts. Switch cleaner will loosen the dirt and if you use too much will also swill some of it out !  However this is NOT the most effective way that it can be done . Certainly use switch cleaner to loosen the dirt, preferably a type of switch cleaner that evaporates and does NOT leave a deposit. Then using  a rough piece of thickish paper pass it between the contacts that are closed - simple as that. Heavier deposits can be removed with the aid of the contact cleaning "pen" that I sell with the stiff fibre glass tips -very effective. You can buy contact burnishers, which if you get the correct grade, are also very effective. DO NOT use course emery paper, sand paper, Files or Wire Wool -- if you do then a nasty disaster could be waiting just for the switch you use it on. When cleaning the contacts you should aim not to scratch or rough them up as this uneven surface can promote electrical arcing.
Adjustment of these types of switches is often bodged. Lets look at a typical type:

You can see from this simplified diagram that  there is a central moving leaf which has a leaf contact to the left and to the right. The central leaf has two contacts so that it can make to the contacts on the left or right leaf whichever way it is moved. With extended use the leaves start to lose some of their tension, the contacts wear down slightly and so the contact force becomes less and less : result in switching failure. Cleaning the contacts will not help this problem. Obviously the contacts need to meet with more force to ensure a positive switch action. How is this often achieved : people BEND IT and that is wrong ! So  how do you do it ? Do NOT bend the leaves of the switch as you will then make the contacts touch at an angle instead of square on. This can also give a poor switching action and will lead to uneven wear of the contact, thus creating the problem again, but this time the contact will need to be changed.
It is simple all you have to do is move the short 'tension'  strips at the side of the contacts either towards or away  from them. That is their purpose and usually that is all that is required to alter gaps/pressures.
Check it out when you next have to fiddle around with this type of switch.

Jukebox Lighting

I have been answering the same old queries about jukebox lighting quite a lot just recently. Things tend to go around in circles I notice. Fluorescent tubes are the main type of cabinet lighting found in jukeboxes apart from light bulbs in the early ones. Fluorescent light was first exhibited at the Chicago Centennial Exposition in 1933 and came into popular use in 1939 and by the 50's had largely replaced light bulbs in most commercial establishments. Fluorescent lamps (flo - tubes) emit more light per watt than incandescent (normal) light bulbs. Their light is generally "whiter" than ordinary electric lamps and if the chemicals in the interior phosphor coating of the lamp is changed different light tones can be produced.

The heat produced is less than that of bulbs and the added bonus is that the tubes give a greater, more even, spread of light over their length than light bulbs thus giving us ideal decor lighting for a cabinet,such as a jukebox.

How they work.

When the lamp is switched on a stream of electrons flow between the two ends (the electrodes), bombard the glass tube,excite the fluorescent powder, causing it to fluoresce, and produce the characteristic light. Well that's fairly clear - I hope. Initially the flow of electrons has to be started.This is done by preheating the electrodes by means of the starter (there are other types of circuitry but let me try to keep it simple and as applied to most jukes that I've seen).

The starter as we all know, is a small metal or plastic canister. When the light is switched on,contacts in the starter close and after a short interval during which time the electrodes are heated, the contacts open causing a surge of high voltage from the choke (or ballast) which is discharged between the two end electrodes and initiates the electron flow. The choke then acts as a current limiter: stabilising the current at a level needed by the lamp. Unless controlled, the current within the lamp would continue to increase until the lamp fails : as when you have a short circuit choke....a very bright light for a very short length of time resulting in a useless flo tube. Never use any choke (ballast) except the one that is designed for the specific use it is put to. One of the by-products of the choke limiting the current is heat .

The heat produced by the choke (ballast) is enough when the component is used on the correct mains system for which it was designed.....for example: 240v 50hz chokes run warm on 50hz mains systems AND 110 volt 60hz chokes run warm on 60hz mains system HOWEVER if you take the 60hz choke and run it at 110volts BUT on 50hz system just like we do with our jukebox lights the result is that more heat is produces than is normal or healthy for the chokes. A way to prolong the life of your jukes wound components (not just the chokes) is to use a stepdown voltage of 100 - 110 volts and certainly no more than 115 which is plenty - over 115 and things can start to get rather too warm.

When replacing lighting components it is important to remember to order the correct type of choke both by volts and wattage. Equally as important is the starter's volts and wattage.Tubes are only rated by wattage - diameter and the length , which is measured to include the pins .
If you have a flo tube that is being particularly stubborn at lighting simply try refitting the starter 180 degrees to what it is : ie the two pins of the can need to swap places and this may help it to start quicker. "Fat tubes"or "Thin tubes" ? That is the question quite often asked. Well fat ones T12(1.5inch diameter) give out a bit more light but are classed as energy inefficient : "energy guzzlers". So the thinner type T8 (1inch diameter) are more efficient at converting the energy into light but often are a lower wattage output by a couple of watts perhaps.

Unfortunately the thin type of say 30" in a Wurlitzer 2300 series will not light but the fat ones do, likewise some jukes that use thin ones will not light fat ones , but I can't say for sure why! Many thin tubes will work on 60 cycle mains bettter than on our 50 cycle mains and some are made for use in conjunction with the quick start electronic system and really only work with that system. In the not to distant future I have heard that the flo tube manufacturers will stop making the T12 tubes. Indeed at times it is already quite difficult to get certain tube sizes but ,hopefully, production will not cease entirely although demand is bound to fall as other lighting systems that produce higher savings become more and
more popular.


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Unit 11, Whisby Way Business Centre, Whisby Way, Lincoln, LN6 3LQ
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