Danson

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Danson Instructions

 

DANSON

 

For some reason, I find the Danson a fascinating little machine. After reading this, you might wonder.

The Danson machine seems to have been aimed at salesmen - a very compact, two-case machine ideal (?!) for carrying around to customers. Not clear why it's a left-hand threader, tho'. And pink as the theme colour for the publicity blurb?

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The adverts are from ACW and Film User. I have used the Danson in the section on old projector amps; the relevant bits are repeated below. Sadly, it seems to have ended up remaindered @ £60.

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dansonHere is a Danson amp. Originally Italian made, some parts of it came to be replaced or added in this country. This is one of a batch of no less than four that I had on hand. There are various minor differences, but nothing very major. The oddest feature of the Danson is its switching. There is a switch on the base of the amp, just inside the door. On one machine this is a push-to-make switch that presumably acts as a cut-out when the amp door is opened. Others have a standard toggle switch; this may, of course, be a customer modification rather than an original feature. There are switches on the front panel for sound (this actually operates the exciter) and projector. But the projector switch does nothing until the on-off switch incorporated into the tone control knob is switched on. The valves light up whether this switch is on or not, tho this could be just the heaters.

 

dansondansonA couple of shots of the amp out of its shell. Removal is mostly straightforward, four screws from the bottom of the machine to undo and two connectors, a multi-pin job next to the tranny and a co-axial type, which is the feed from the PEC. BUT BE WARNED! It is essential to extend the front feet of the projector (used for tilting) to their maximum extent before moving the amp. You can see from the absurd capacitor standing right up from the rest of the amp how hard they worked to shoehorn the amp into a very confined space; another problem is that the big tranny tends to foul the socket for the front feet and, if not unscrewed, the shaft of the foot would prevent removal of the amp altogether.

Note that on this amp, the speaker socket is a jack that I fitted instead of the unusual 3-pin Danson type, which I don't have for this particular machine. I also had to replace the fuse carrier next to the tranny at the back; it was loose because the threaded plastic body was disintegrating. There was also a problem with this machine at the amp inputs behind those voltage change pins, with a loose connection stopping the machine working at all.

 

danson dansonThese are before and after pictures showing the change of capacitors. It is easy to see that four tubular ones have been replaced by much smaller, square, red ones. Top left is a pair of caps; the replacement for one of them is, as you would expect, much smaller than the original. But the other is if anything larger, and I have no idea why. The three blue caps bundled together top right deal with smoothing for the early stages of the amplifier and are less critical to change. So if you are able to solder, the job is not too bad, tho later machines with printed circuit boards are a whole otherkettle of fish.

 

 

 

When there were only 3 machines (the fourth came a bit later), we found only one functional EZ40 valve between them, tho the rest seem broadly OK. The valve layout is helpfully printed on a plaque. Looking at the LH pic, the front are 2 x EL41 and the aforementioned EZ40. An ECC40 and EF40 complete the line-up. The EZ40 is the rectifier providing DC power to the whole amplifier. The EF40 is a pre-amp pentode which amplifies the output from the PEC. The signal then goes to the volume control. The ECC40is a double triode valve. The first section amplifies the signal from the volume control further and the second is the phase splitter used to divide the signal into two halves suitable for feeding the 2 EL41 power pentodes. These form a push-pull output stage giving approx 8 watts into the speaker.

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There seem to have been one or two other machines of a somewhat similar design; here is the Movie Mite. One assumes the arms slotted into the body as per Danson.

 

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Paul Schimmel writes about the Danson projector as follows.

"The Danson is actually of Italian design by a firm called SAFAR (Societa Anonima Fabricazione Aparecchi Radiofonici). The original loudspeaker fret had
this moulded in. The original amplifier was based on side contact valves (never common in the UK). Although the blurb talks of 'English type
valves', I suspect the amplifier pictured is Italian.

At some point in the mid 50s the 'Danson development company' went bust and was bought by Beam-Echo (also responsible for Avantic HiFi gear)
they went over to using a British amplifier based around the Mullard 40 series valves. The panel then has 4 (I think) white control knobs. The
'SAFAR' decal was then removed from the loudspeaker fret. I suspect that the whole projector was still bought in from Italy minus amplifier which
was then added in the UK. The model was then known as the 'Danson 540'

In around 1960 Beam Echo were bought by EMI and shut down. The 540s were being sold off cheap around this time. Danson is supposedly named after a local park."

 

Paul is a collector with projector and other interests; his website is www.schimmel.webspace.virginmedia.com/ He has also sent copies of 2 ACW pieces on the Danson.

 

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I have been trying to bribe Paul with promises of one of four Dansons currently in my hands (only one being really mine), 'cos he can do amps and I can't. We only get a couple of hours on occasional evenings. So far (this is July 2010), we have gotten 1 amp working pretty well, but the projector runs rather slow. Paul took the amp from another away with him, as it was doing incomprehensible things, This is the one that's mine, so I have taken the opportunity to dismantle the mech, to see if I can identify any possible causes for slow running.

And what a can of worms it is. Lets start with two general views of the dis-assembled mech, front and rear, plus two views of a very busted flywheel.

 

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The mech is attached to its casing by four bolts, which can be seen more or less at the corners of the front view. Originally, these bolts were fitted with rubber mountings, which have disintegrated into a mess of some sticky but mostly brittle gunk, which I have removed. You cab see the stuff had rotted the paint round the bolts, too. In this view, I have also removed the claw cover, the motor speed control cover, the sound drum and the two-stage exciter lamp cover, plus the somewhat unsophisticated multi-point oiling system, which feeds just three points, cam and rear claw pivot and flywheel bearing. Also loose, on the right, is the PEC mounting, to which I shall return. The speed control is an odd item; there is a screw-threaded knob on the cover for the speed control, and all it can act on is that odd little pivoted thing, here in the "open" position - you get another view of this in a "closed" position later.

In the rear view, you can see the four odd-shaped blocks on which were mounted the outer bearings for the flywheel and the shutter (this plate also houses the [cracked] condenser). The flywheel did not want to come off; in the end it broke rather than move. I have included a pic to show what it was like before I destroyed it, which also reveals the highly-sophisticated multi- (OK, three-) point oiling system (the tube rising alongside the lamphouse joins the little "bath" at the top, which contains a felt pad. The tubes also seem to contain string wicks).

You should be able to see where the three spokes between the rim and the centre were attached; there are also some pix of the much-traumatised centre. I'm not really sure what happened. I could understand there being some distortion - it's made of very Mazac-like stuff ( I can see cracks in one of the other, still intact, flywheels), which would tend to make the flywheel jam on the shaft - but there seem to be spline-like rings round the shaft that might also have contributed. But this would be daft, as it would make it nigh impossible to remove. And why would you fit TWO securing screws if you had splines and ifyou did not intend it to come off? In the end, I had to saw/drill/hit the centre of the centre off the shaft, and I am now faced with an interesting repair job.

You can see there were three springs, sort of riveted to the flywheel, which nest into those holes in the big brown gear wheel. I'm not sure I understand these; the effect in situ is to give the flywheel about 0.25 inch springy movement either way relative to the gear wheel, so I suppose it gives a bit of damping as the flywheel is started from scratch. But it must also act when it stops........ I need to think about it.

You will notice that, through all of this, the main drive belt remains in place. I suppose part of my plan was to try to replace it, on the grounds that it had probably stretched and would cause reduced speed. However, to get the belt off I had to go even further; I had to prise off the mini bearing on the shutter shaft, because the big gear wheel simply would not come off else.

danson    Then I had to remove the speed control/governor unit (the screw that holds it has a LEFT hand thread) and the brushes underneath, remove all four screws securing the motor to the main mech plate and finally disconnect one of the wires from the motor to the speed control/governor brushes. Then, and only then, could I remove the belt. This is insane. What an appalling piece of design (left is the machine fully disassembled for belt removal). All right, there have to be compromises to squeeze everything into such a small casing, but to have to virtually completely dismantle the thing to change a belt! Actually, the belt on this one is still in very good shape (it's a solid, fabric-reinforced flat-bottomed V,) but it cannot but be a bit on the loose side. I've found a round rubber belt of about the same size, but to try it I shall have to virtually re-build the projector. What fun - not.

 

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Here are close-ups of that speed control thingy in open and closed positions, then a view of the exciter lamp covers (basically the inner cover holds the lamp down against a sprung contact and the outer cover is secured to this by a ring nut rather like those used for panel-mount switches). Then we come to the PEC. What you see here is the base of a PEC of the type fitted to the Debrie D16, ie with a modern thin-pin valve base. The highly sophisticated connections are tiny thin strips of brass , folded over, with two tiny holes each for the valve pins to pass thru. Alignment to the exciter seems to be by guess. There should be some kind of cushioning pad at the head of the PEC and presumably round the PEC to hold it. In fact, it looks like what we have is a nasty rubbery mess. (I discovered I had maligned it; very good bits of rubber, in fact). In order to insert the PEC into its housing, you have to pull the wires up through that channel they're in, to give enough slack to manoeuvre. While you do this, the connections come off because you are twisting and straining them. Another shocking piece of "design", if one can call it that.

 

 

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Just a couple of general close-ups; note the prism rather than a mirror; then the sound drum housing and the drum itself. The film retainers are a very close fit; they have a slot in them to accommodate the sprocket teeth. The final pic is a blow-up from the pic at the top of the page showing this part of the machine (not the same one, tho') with everything actually in place. I'm off to make a new flywheel.

 

And here it is.

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I should explain that I had to hand a round piece of aluminium, with a hole in the middle, a failure from a motor end-cap attempt. What I did was to cut out the inside of the old flywheel to match, leaving a "shelf" approx the depth of the original 3-piece "web" of the flywheel. The new centre then sits on this shelf, as in pic 1 above. I had to drill holes thru the circumference of the flywheel into the new centre, to take screws to ensure it was held rigidly together. You can just see two of the four holes - the screws are sunk in below the surface. Then I had to fit a new core, as the hole I already had was way too big. Basically, I just took a slightly oversize bit of alu rod and forced it in. I did much the same with the three pins that locate the springs on the other side of the flywheel. The new core carries the screws to secure the flywheel to the shaft, so I had to cut away the inside of the new centre to make room. I also cut channels to make screwdriver access easier. I can tell you it took a bit longer to make the flywheel than it has to write about it - I mite with hindsight have been better off just making a complete new one.

I am now in the process of reassembly, but can't get very far until Paul has seen to the amp. I'm trying to fix up yet another Danson now I've sorted the flywheel problem. If only I could get the amp to work, I could test it in the one with the repaired flywheel. But I can't.

Actually, that's not strictly correct. I do, of course, have a working amp from the first projector we worked on. Sound was OK but proj was definitely slow. Put it in with my re-belted mech and Whizzo! Bags of speed - had to crank it down a good bit - and volume, much of it achieved, interestingly, by turning up the tone control, which had more impact than I am used to finding. Only problem is the mech is making a rhythmic noise. I did notice the shutter was scraping a bit when I had it apart. I am not sure I want to go back in and look any further, as I have no plan for extended use.

So now we know:-

a) the amps can work well;
b) the speed problem is probably the belt; the one I replaced is fine in terms of rot/durability, but appears to have stiffened up and has slight kinks/bends in it. I think these two factors, plus maybe a bit stretching, account for the low speed achieved;

c) replacing the belt is likely to mean replacing the flywheel, too.

The Story Continues

I have been dabbling with Dansons again, having got the latest amp back from Paul. My original Danson is now up and running, with a new belt (and as a result, a new flywheel). One of Patrick's 3 original machines is working but running slow; I have hesitated to meddle because of the flywheel issue, and instead moved on to the machine destined to be Paul's bribe. The flywheel came off with no trouble, but the machine seemed fast enough so I didn't replace the belt. The speed control was not functioning, however, which proved to be because of a fairly spectacularly-melted capacitor.

I have learned yet again just how anti-people projectors can be. I had the amp and the mech in and out umpteen times, cos you can't get to do anything without full access to the mech. All the clearances in there are incredibly tight, the result of trying to pack so much into such a limited space. On my first attempt, the mech barely turned over, and was almost impossible to move with the inching knob, which is anyway quite high-geared. I discovered that the exact position of the flywheel on its shaft is critical to both letting the mech move reasonably freely and, even more vital, with ensuring the single sprocket is actually in the right plane to and fro otherwise it don't match the film guides/retainers or, indeed, the sound track reader. To help free the mech, I also removed a dished, sprung washer from the back bearing of the fan. It wasn present on my machine, and removing it seemed to help a lot.

I have had continual trouble with fitting the spool arms back into their homes in the front door of Dansons. This was because of the take-up pulley, which simply did not fit. This meant one had to remove it (it came off far too easily and I had to tweak the fitting a bit) with no place to put it, so it just sloshed around loose. However, with this machine I discovered that a place to put it existed on the back door, a small shaft just like the one on the spool arm itself. This was obviously missing on mine.

Another thing I discovered was the danger of too much oil. There is a limited centralised oiling system, with a little reservoir with felt in it. It was, of course, bone dry, so I gave it some oil. I subsequently found oil dripping from the end of the flywheel shaft straight onto one of the valves. In a typical example of laziness, I declined to remove amp and mech for the 37th time and poked a rag down thru the oil hole with a screwdriver; a few repetitions of this soaked up much of the excess. You see what I mean about projectors hating people? (well, me at least).

One thing that did work well was replacing the rubber bushes on which the mech is mounted - I think mounting the amp flexibly is more common. I found two sizes of standard rubber cable grommets did a good job. The larger ones fitted the mounting holes just, and with a lot of bullying. Smaller ones I cut in two and discarded the centre section. As mounted, we have the mounting pin sticking out from the mech, onto which is placed one of the small half-grommets. The pin is then passed thru the larger grommets, as bullied into the mounting holes, then a second half-grommet, a washer and finally the nut. (Interestingly, these nuts are like the ones often found on Pathé machines, round and with a screw slot).

One mod that I am making to all the Dansons I have is to saw off the top of the threaded tube for one of the front feet. This tube is far longer than it needs to be to do its job, and it fouled the main tranny each time you move the amp as is obvious from the visible damage. You may recall that anyway one has to unscrew the feet to get the amp in or out at all.danson

When I re-started my Danson dabbling, it was borne in on me that I had promised two working machines to Patrick and one to Paul, but only had three pairs of spool arms (and two speakers, three if you count the one I passed on to Paul a couple of years back), leaving me a bit bereft. However, this time providence smiled on me in the form of a very kind gentleman who had contacted me some months ago via the website. The weather having improved, he duly rolled up with, inter alia, a beautiful, shiny, hardly used Danson in a beautiful blue colour, with matching speaker and a spare grey speaker! Oh frabjous day! So now I can fulfil my pledges, retain a working spares machine lacking only the spool arms (has anyone got some?) plus my new blue one.

Still a lot left to do. Have to go back now to Patrick's first machine to see if the flywheel will come off and see if the belt does need replacing. I then have to move on to his second machine, which is a later model, after the name-change to Beam Echo, with a different valve layout. I assume my blue one is like this too, and of course that has to be checked over.

I have now got two sets of Danson Instructions, which I am cleaning up for your edification.

Having established that the Beam Echo (BE) Danson amp worked fine out of the machine, I needed to try it with a film to see if sound was OK and speed was OK. No. A little bit of sound is all not enuff to check speed even. I find, too, that the PEC is completely different. Instead of looking exactly like a miniature valve (the same PEC as in Debrie D16, actually), its just a glass envelope with two wires emerging. I ent never seen another like it, so finding a spare could be tricky.

On guidance from remote Guru Paul, I checked the voltage across the cell connections about 15v, way below 60-90 range it should be. He then directed me to check another point on the underside of the amp so out it comes again. Now we have nada; I await further guidance.

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Bin mucking about with Dansons again. Have now got a Beam Echo, ie somewhat later, machine working well. Interestingly, I think it's rather less well finished both cosmetically and in engineering terms than the earlier one currently on the bench. Inter alia, it has an unusual photocell, just a round tube with two wires emerging from the end. I'm still learning how best to do Dansons; here are some points I've come across recently. The damping roller between the lower sprocket feed out and the take-up arm can foul the casing if you need to take the mech out. See pic 1 below for the simple precaution of a rubber band. 

Dismantling the Danson is at first easy. There are four screws on the underside that retain the amp. This is one of the ways the beam Echo is lower standard; it uses ordinary wood screws, not even proper self-tappers! But before you remove these, disconnect the multi-way plug that connects the projector to the amp and the co-ax plug that connects to the PEC. Both can be seen clearly in pix 2 & 4 below. Make sure the tilting feet at the front of the projector are unscrewed as for maximum tilt. It should now be possible to slide the amp out, altho' I have found that the tranny still can get fouled up on the tilting foot casing, so great care is needed. Also, the big capacitor, seen on the left in pic 2, may also get hitched up. The two plugs you have removed also pose a risk, so you need to unhitch them several times as you gradually ease the amp out. This is the time to take a hacksaw to the tube in which the front tilt foot is housed and remove the top half inch - it really isn't needed and the alternative is that you will one day damage the tranny wiring and render it useless.

 

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Having done that, removing the mech from the casing is fairly easy. There are four Pathé-style nuts (no facets and a slot across the middle) on the front of the machine, clearly visible in pic 3 above. Once they are removed, the whole mech should come out, tho' age etc may make it stick and/or rot the rubber grommets thru which the fixing screws pass. In pic 1 you can see the fixing screws after you remove the mech. This is when it starts to get tricky, so I'll leave that for now. 

I had a major problem with the Beam Echo Danson.

 

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Pix 1 & 2 show the exciter lamp socket front and rear. The screws pass thru the main plate of the mech from behind. You can only get at them by removing the lamphouse, fan, flywheel, condenser and bearing block and the main gear wheel. The front should have 2 lugs, but they broke off because this part is, as you will have guessed, made of Mazac. The function of the lugs can be explained with the help of the next two pix. The lamp goes into the socket from the front, and meets a springy strip which is the centre contact for the lamp (visible in the final pic above). The lamp is held in place by the gizmo on the left; it has two pins which, if you squeeze the sides of this part, could be inserted in the aforementioned lugs, which stood proud of the flat surface of the holder in pic 1. You can probably see where I filed them off flat. Because, of course, I tried repair first and actually succeeded with one, but the second then went too and the whole thing started to crumble, as you can see. For some reason, presumably ventilation, there are holes drilled so close to the periphery that their outer edges had crumbled. So I had to make a new one, and it's actually quite a complex little thing. Note also the screw-threaded thingy at the other end of the gizmo; this passes thru the hole in the cover and a sort of nut (very like those used when you fit switches thru a hole in a plate) then goes on and holds the whole thing together. 

The end result can be seen in the final pic. I made it in two sections, because I could see some bits would be tricky if I didn't. You can see the screws that secure the outer part to the inner; the join is where you can see the separate levels in the middle. I also decided to avoid lugs and use a complete circle, as I wanted the extra strength. You can see the cut-outs that accommodate the pins on the inner gizmo. It has to be fairly precise so that you can squeeze fit the gizmo without having to squeeze it so much that the lamp gets in the way. There is also the cut-out for the centre contact, and a slot for a little spring contact onto the side of the lamp, which I would not have thought necessary. This aligns with a slight enlarging of the hole in the mech plate to accommodate the screw that holds this spring. I got mine in the wrong place by a small amount and had to file away a bit more of the mech plate in consequence. Everything has to be just so or there's a problem. You can see I replicated the holes round the periphery where I had room.  

Anyway, I think I have finally reached the end of my current Danson work and 3 of the machines will now be going to their respective homes. I could not of course resist the photo-opportunity.

 

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From the left, we have a working machine but a bit noisy and no spool arms; I shall keep this as a spares machine. Then there is The Beautiful Blue Danson (waltz by Strauss), which I am putting aside for now and will look at later. Then we have a couple of Danson-branded machines, followed by the lighter Beam Echo. Finally, the manky object on the end, enlarged in the next pic, is a very early speaker when the Safar brand was more obviously in evidence, tho' it still appears on some parts into the Beam Echo era, viz and to wit the exciter lamp holder pictured above. The speaker was incidentally donated by Tony Reypert. I think a clean and a light spray with metallic silver would make it look pretty good.

 

 

 

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