Repairing a Casiotone 101 synthesiser

As I’ve mentioned in previous posts I am interested in sound engineering and technology, and I love all kinds of music tech although this far outstrips my musical ability. So I’m keen to take any opportunity to get hold of something interesting, even though this often involves working out what to do with it later. I have acquired a number of interesting items this way, some of which I have kept and some I sold on. I still have a Casio VL-Tone VL-1 and I also had a boxed Casio SK-1 although I did sell this one on.

I was at our local rubbish dump the other day, and out of the corner of my eye I saw someone with an obviously old and classic looking synthesiser in the back of the car which was clearly heading for the ‘electrical’ skip. It turned out that this had recently “gone bang” and had been left out in the rain for a few days. The owner was quite happy for me to take it off his hands. On closer examination I found that I had scored a Casiotone CT-101:

casio_ct101

I’ve found a few references to this online which are mostly fairly derogatory, and whilst I suppose this is nothing like a Fairlight or even a DX-7 it is still an interesting bit of history, and from a similar era. It dates back to 1981 and must be one of Casio’s first attempts at a professional grade musical instrument. You can see the legacy of the 1970s era ‘home organ’ with the large multi-coloured controls and woodgrain finish. However the sounds are beginning to make the transition from organs to a classic 1980s style synth.

First impressions on getting it home were positive – it’s really well built with a solid wooden case, metal panels and very chunky controls and jack sockets on the back. Unfortunately there is evidence of water damage – mostly to one of wooden end pieces which are chipboard and have absorbed a lot of water leading to swelling and cracking. This is a real shame because this is obviously recent and the rest of it is in good shape.

Given this history of it going bang I didn’t try plugging it but stripped it down to find the problem. The obvious place to start is the power supply, and I was hoping to find a fairly simply fault.

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The internal construction is again very well done and surprising simple. The wooden casing is very solid and the PCBs are slotted in to small guides with lots of discrete wiring. There is lots of room inside to work and it’s easy to find your way around. There are a lot of screws to remove at the back and underneath, and the keyboard itself plugs in via a ribbon cable which you can pull out gently from the PCB connector.

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A close look at the power supply PSU quickly revealed this:

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Most of it looks good but this component (labelled PME 265) has clearly failed. There were bits of it all over the inside of the case, and there was no sign of any other damage anywhere. The damage to the component made it quite hard to see exactly what it was, but after gathering together the broken bits and with a bit of searching around, I found it was a Rifa PME 265 0.02uF capacitor. I think these are used for smoothing / interference suppression in the mains supply.

This specific part is no longer made but a newer version (PME 271) is readily available on ebay. I was able to find a replacement (a PME271) for less than £3. I was surprised by the capacitance rating though, I’ve never seen them measured in Nf before:

rifa

The new part is almost identical in size and shape to the old one, and the manufacturer is the same. Replacing it was very easy, just a few screws to release the PCB and I was able to replace it in situ without removing any of the wires by twisting it around and resoldering it. This is the old and new part side by side. No prizes for guessing which is which!

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Then it was simply a matter of reassembling and testing.

Then comes the moment of truth… and success! No bangs or smoke, and it works perfectly. I absolutely love the chunky controls (orange and blue toggles and press buttons as seen on the photo above) and the sound is very reminiscent of the early 80s. Now need to think of something to do with it… although looks great in my ‘home studio’!

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Repairing a Spirit Folio SX rack mixer

I’ve written before about my interest in sound equipment and engineering, which mostly relates to work at my church. As part of this I do general maintenance on the equipment and where possible do repairs to keep it all working. Given the cost of pro-audio gear this is generally cost-effective and also it’s satisfying to keep stuff working rather than buying new.

We have a mobile rig and part of this is a fairly old Spirit Folio SX rack mounted mixer. The one we have at the moment looks like this:

Soundcraft Folio SX labricox images

It’s not quite the same as ours has rack ears but the principle is the same. One of the main problems with these is the power connector, which because it is a rack mount is on the underside of the desk. It is a small proprietary plastic connector which looks like this:

It’s small, flimsy and easily broken. There are three pins because the power supply is a little unusual, being 2 17V AC lines with a 0V in the middle. I’m not entirely sure why it needs this, possibly something to do with the phantom power (which is 48V) used to power stage boxes and certain types of microphone.

When I was given the desk to look at the power was flickering on and off and it was immediately obvious that the power plug was loose in the socket, wobbling around all over the place. There was a small catch on the top of it and when I tried to move it it broke off in my hand. So the first step was to replace the power connection.

A lot of other people out there seem to have had very similar problems and there are a lot of people on various forums complaining about the same thing. There are a number of ideas, including removing the connector altogether and wiring the power supply straight in as a captive lead. Other people have used various types of XLR connector. We have loads of these lying around, but I thought it was better to avoid using these in case someone accidentally plugged a microphone into the power supply!

I finally settled on a locking 3 pin microphone connector, as seen on aircraft and various amateur radio equipment (another interest for another post).

To make it a neat job I decided to bolt a suitable socket to the bottom of the desk in place of the existing one. The connectors themselves are easily available on ebay:

connectors

The socket needs a 15mm hole which is too big for regular drill bits (the largest I have is 13mm) so I needed a suitable hole saw. Once again there was a wide choice on ebay and I found this for the bargain price of £2.79:

Image result for 15mm hole saw

Great service as usual from ebay traders and they were delivered quickly. The hole saw is from a Chinese manufacturer but I was impressed with the quality of it.

The bottom of the desk is a steel panel held on by a load of screws but fortunately there is quite a lot of space between the panel and the circuit board underneath. There is plenty of space to fit the new socket and connect the wires up without it fouling the board underneath.

First step was to remove the old socket which simply pulled out, and cutting the wires. Then I offered up the socket roughly to where I wanted and made sure that there was space to connect it up. Drilling the hole with the new cutter was pretty easy – I drilled a pilot hole first, and then used the cutter with a block of wood underneath. It did a great job and cut straight through leaving a very clean hole.

The new socket bolts through from the bottom with the supplied nut and washer. Then it is a matter of soldering the wires on to the connector. As above the power supply has two 17V AC rails and a ground connection. I traced these out using a meter and wired the plug and socket to match. The only problem was that the cable on the plug end was a bit thin for the cable clamp  so I had to bulk it up a bit with some insulating tape.

 

I also found that if I turned the panel around I could cover up the hole than the old power socket was in, which finished the job off nicely. After reassembling it, the power is now rock solid and various other odd problems have resolved.

You could use pretty much any connector to do this but this one was good because it was cheap and the locking mechanism made it very unlikely to fall out. I’d definitely recommend this as a modification as the original connector is a poor design and I’m not surprised that others have had problems with it.

Repairing a Roboquad

I’ve always been interested in robots, and in recent years some of the stuff available as toys has been really interesting. One of the main players is Wowwee who have over the years produced loads of interesting stuff, perhaps most famously the Robosapien which has been through several versions over the years. However they have done others too. I bought a Roboquad off ebay a few years ago:

 

Roboquad

This is a very clever design which uses only four motors (one per leg) to move around using crab-style walk. The head and neck is also articulated, and it has light & IR sensors in the eyes. There are loads of programming options and for a toy it’s quite advanced.

It’s been put away for a few years, and when I got it out again I found that because I’d used cheap batteries in the remote control (never a good idea) they had leaked acid everywhere and completely rotted through the springs and contacts completely destroying the battery compartment. To make matters worse when I put batteries in the robot itself it was completely dead and didn’t power up.

So before throwing it out I decided to investigate further. Unfortunately given that this is now quite old a lot of the info about them is hidden away in old forums but I was able to find a basic disassembly guide.

You have to start by turning it over and removing all the screws in sight, including one in each corner which is hidden under the leg. Once you done this you can separate the top and bottom, but you need to be careful to unplug the cables which connect the sensors from the head to the main board.

Given that it was completely dead, I did a few tests to make sure that the voltage from the battery was getting through, which it was and there was nothing else obviously wrong. So the next step was to unplug all the connectors in sight and get the board itself out. You need to be quite careful doing this as there are lot of them and some of them are quite stiff, but with a bit of gentle pressure you can get them all out.

I had a good look at the board when out and there wasn’t anything obviously wrong with it. However what I have learned by now is that the most likely point of failure with modern electronics is the large discrete components like electrolytic capacitors. So I desoldered and removed the largest ones and replaced them with some new ones.

I wasn’t optimistic, but to my great surprise once I had reassembled it the robot now worked fine! It’s possible that it wasn’t the capacitors, and it might have simply been the act of disassembly and reseating all the connectors but either way I was pleased.

The next step was to fix the remote control. Whilst the battery springs were completely destroyed by the battery acid, the actual contacts themselves were OK. So I tried jamming the batteries in with some coils of unused solder as impromptu springs. This worked up to a point but it wasn’t reliable and I gave up. The only thing to do was replace the battery holder completely.

The remote uses 3 AAA batteries, and fortunately a suitable holder is easy to find on ebay and other sources:

Image result for 3x aaa battery holder

Then it was a matter of fitting it. The original remote had the battery holder moulded out of the plastic the back was made out of. It originally looked like this:

So what I had to do was break out the trusty Dremel and use it with a cutting wheel to remove the whole compartment. This turned out to be quite a job because the plastic was surprisingly thick in places. However eventually I was left with this:

The battery holder just fits through the hole, and the battery cover holds in in place perfectly. Having resoldered the wires I now have a working remote as well.

So all in all a good result – both robot and remote repaired and working for total expenditure of a few pounds. Hopefully this may help other in the same situation as I found it quite difficult to find much useful info given the age of these toys.

Repairing a (fake) PS3 Dualshock 3 controller

I’ve had a PlayStation 3 for a few years and although I don’t play it much it is a fun thing to have around. I got it second hand from CEX some years ago. The controller that came with it was a bit shabby but worked OK and has done for a while. I bought another one along the way.

Just recently one of them stopped charging. Reading around a bit it at first seemed like a battery fault so I ordered a new one. I consulted various guides (including ifixit) and it seemed a simple matter to replace. However, once I got it to bits I was surprised to find it looked rather different inside than the photos.It looked a lot more basic and quite a few bits were missing. Something like this:

I’ve borrowed this picture from another blog, but mine is exactly like the one on the left versus the other one I have which I think is a real one, which looks like the one on the right:

Image result for fake ps3 controller

It is obviously a fake and much more cheaply made that the real one. It seems that there is now a huge industry in faking these controllers, and given the PS3 is now discontinued it seems to be increasingly hard to buy one which is genuine. The packaging etc is all very closely copied and umpteen ebay or Amazon sellers say that they are ‘Official Genuine’ but it seems very likely that they aren’t.

Having said all this, in use the fake controller is (to me anyway) almost indistinguishable from the real one. Also I didn’t really want to have to pay out for a new one so I investigated further. Once I changed the battery, the fault remained. On plugging it in, the four red lights would flash for a few seconds and then go out. I had read elsewhere that the controllers do need a ‘proper’ USB connection to charge, and so I wondered whether the problem lay in the USB connection itself.

The USB socket on the fake controller had been damaged for ages although it didn’t seem to affect it in use. However, it was very loose and looked bad, so the next thing to do was replace it. These controllers use the once-common mini-USB connector, but they are still easy to find on eBay:

usb

The only problem I could see is that it is quite awkward to solder given the very small pins. However I thought it worth a try. I used my combined solder sucker / iron to remove the old socket and clean up the holes:

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I’ve taken the board completely out of the casing here and you can see the vibration motors at the bottom.

The new connector fitted well and it proved easier than I thought to solder it in again. The key was to use very small amounts of solder and get the joint heated up properly. The pins were so small that they wicked the solder off the end of the iron and on to the pad with relatively little effort.

Putting it all back together I did some have problem with the ribbon cables connecting some of the buttons together, but after a bit of wiggling it all went back together and now works fine again. The connection is positive and firm as it should be now and it charges from the PS3.

So even a fake controller is worth repairing… and it looks like if I need any more controllers I will have to put up with fakes. Having said that for my purposes they are probably good enough!

Repairing a Dynamode SW240010-R switch

At church we have a combination of computer and audio gear which I am loosely responsible for maintaining, and I’ve written about some of this before. A couple of years ago we rationalised the racks by the computer and as part of this I put in a rack-mounted switch. I was on a budget so ended buying as new from ebay a ‘Dynamode SW240010-R‘.

This was inexpensive (which is why I bought it) and ‘as new’ from ebay. I was a bit wary of it because I wasn’t familiar with the brand but it looked OK and worked fine when installed.

However, a couple of weeks ago it became clear that the network wasn’t working, and one glance at the switch showed that it had failed. The main power light was flashing on and off weakly and none of the individal port lights were working. There wasn’t much time to consider a fix as it was important to get it going, so we bought a new one (TP Link this time). However I wanted to see if the Dynamode could be reapired. From recent experience, I have found that a lot of these failures are due to power supply problems – and specifically capacitors. Particularly in cheap equipment like this the capacitors are of poor quality and deform when they get warm over time. The actual solid state stuff is pretty robust these days and much less likely to fail. The voltages from the power supply wander all over the place and this causes very strange behaviour.

Opening up the unit as expected there was a small power supply board and quite a lot of fresh air:

psu

What was immediately obvious was that one of the capacitors was obviously bulging (circled in red above). It is a 10V 2200uF part, as is the other one on the right hand side. I removed the board, desoldered and replaced both of the capacitors, plugged it back in and held my breath…

Success! The switch now lights up properly and works fine again. Very pleasing to be able to get it going again. It is now surplus to requirements for church so will either keep as a spare or sell on. I am confident now that the replacement capacitors are much better quality than those I removed so hopefully the fault should not recur.

Changing the laser assembly on the Teac CD-P1450

The new laser assembly has now arrived, and it looks exactly as it should do – complete with Chinese labels. It is obviously a pattern part rather than a genuine Sanyo one but appears identical to the one I need to replace.

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There are a couple of issue to be aware of if you are attempting a similar repair. There are two variants of the SFP101N – one of them has 15 pins on the laser head, and the other has 16. I don’t know what the practical difference is, but you do need to make sure that you order the right one. The only way to do it is to count the pins which are on a flexible ribbon cable which plugs in to the main board.

The other thing which is important, and which is not entirely clear in the packaging of the new unit is that there is a solder bridge on the laser head which needs to be removed. This is apparently something to do with antistatic precautions, although it is a strange thing. The only way to remove it properly is with a solder sucker. I’ve always had some trouble with desoldering, and in the past I’ve used a soldering iron and a spring loaded pump. This is always a bit fiddly and I’ve had variable success. However, I came across this in the CPC catalogue lately:

desoldering iron

This is a simple combination of a solder pump with a heating element on the tip – so you can heat up the joint and as soon as the solder has melted suck it up in one go.

Here is the new part with the solder bridge intact (circled in red):

 

And here it is after I’ve removed it. It was simply a case of letting the iron warm up, pressing the tip down on the solder for a few seconds and pressing the button to release the plunger. The result was better than I had hoped – the bridge is completely removed leaving the two pads clean.

 

bridge-after

You can see the white connector block just to the right of the bridge – this is where the 16 pin ribbon cable plugs in.

Having got the new module prepared, I now need to install it. Getting the old one out was actually quite easy – the service manual gives details of all the screws etc and I was able to remove the large plastic tray assembly which contains the laser. The awkward bit was disconnecting a few of the connector blocks and the flat ribbon cable although generally with a bit of gentle pressure these came out.

 

The second picture shows the laser mounted in a plastic housing which fits in to the bottom of the tray itself.

Replacing it was a pretty simple matter, just a question of removing the two screws that can be seen above and then pulling the mount out of the the housing by flicking past a few clips. Then there were some rubber boots to come off and then everything put back into place. It was actually pretty easy and I then put the whole thing back together again.

I then took a deep breath, turned the power on and put a disc in…

Success! The disc reads and plays perfectly, and after a long period of testing I’m pretty confident that the problem is now solved. Needless to say I’m pretty chuffed – I’ve repaired the player at minimal cost and in a much shorter time than I expected. If I had had to buy new I would have had to spend at least £180 and I’m very pleased to have avoided this. Also of course… I have enjoyed the adventure of fixing it.

Repairing a Teac CD-P1450 CD player

I love bargains… and I like fixing stuff… and sometimes the two overlap.

At my church I have responsibility for the sound equipment. Every Sunday we have a band at each service, so we are doing live sound engineering wtih a mixture of acoustic and electric instruments as well as vocals, drums etc. The detail of this is probably for another post as there are quite a few interesting things to say about it. However because of this I’m always on the lookout for kit to add in, and we were in need of a good quality rack mounted CD player. These are quite hard to find nowadays because CDs are so out of fashion – you can buy them new, but they tend to be excessively expensive – often many hundreds of pounds. Even ebay isn’t that great for them as the need for rack mount units has never been that great. You can of course shoehorn in domestic players but even that isn’t quite the same. Also, modern units have very few front panel controls which are very important in a sound engineering setup.

I was at a radio rally recently and I happened upon this, for which I paid £10. It is a Teac CD-P1450 which is a rack mount player with lots of buttons and controls and a few ‘pro audio’ features including a tone control.

The one I have got has the proper rack ears, and the feet are removable to allow it to fit flush. I liked the design and construction of it, and a quick test when I got home seemed to suggest that all was well. However, after mounting it in the rack at church it soon became clear that there were problems, and it was jumping and skipping around when playing CDs for any time.

This was very irritating – and meant we have had to go back to an ancient and tatty (and not rack mounted) Goodmans player which was bought cheaply about 20 years ago but has been extremely reliable.

I was on the point of giving up on this as a bad job, but I really did want to get it working. I have read around a bit, and the most likely culprit for these problems seems to be the laser, which is the only thing which is likely to wear out. I found some very technical articles about alignment, focus etc but overall it seemed the first thing to do would be to replace the laser and see where this took me.

I was pleased to be able to find (quite easily) the service manual online (available here among other places). This was unfortunately of little help in fixing it – in that it had no fault finding guides at all – although it did provide a very detailed tear down with every part and assembly right down to each screw individually identified.

Consulting the diagrams gave a promising start:

assembly

And consulting the parts list revealed:

partSo it appears that the whole laser assembly, including the head, CD spindle and other associated gubbins should be available as a single part. This might just be the answer to my problem.

This is where the Internet comes into its own, and I still find it amazing that with just a few clues like this you can track things down. I started with the Teac part number (13933102) which didn’t yield much, just a few references to an old parts catalogue and the fact that it was no longer available. I then tried some searches for ‘laser P1450’ and similar, and I did find an ebay seller in the US who seemed to have the right part. However it would be expensive to ship and cost about £40 all in.

Some more googling around revealed something else interested – there was also an identical version of my player sold by Tascam under the name CD-160. This is not that surprising, as I have now also found out that Tascam is the brand used by Teac for their pro-audio gear. Here is the CD-160 and the similarities are striking!

CD-160_front-dd334569e7891c05fd21f4d401e1ce4c

I think I prefer the rather more sober looks of this one as the red buttons are a bit jarring on mine. I wonder what the price difference was when new – I have always found Tascam kit to be outrageously expensive for what it is and I bet many of their ‘pro’ products are simply rebadged domestic units.

I broadened the search to look for ‘CD-160 laser’ and found a chinese site via alibaba selling them for what seemed not too bad a price – but the delivery will take ages.

However I then happened upon a UK site with something which looked promising:

denon

This appeared to relate to a Denon part, but the picture looked very like what I needed and the part number in the service manual appeared in the list below. I still thought it was a bit pricey though to take a risk on. A bit more digging on the same site turned up an ‘alternative’ part which looked better still:

sfp101n

So it now appears that what I really need is an SFP101N which looks like a highly generic mechanism used by a large number of different manufacturers. Now why didn’t it say that in the service manual! What is even better is that the mechanism incorporates the CD spindle motor, the laser head and the motor and mount which drives it. So in effect almost all the moving parts in the machine except for the tray motor. So whatever is wrong with mine, this really should fix it.

It did strike me that I probably should go back to ebay again just in case anyone there had these in. Once I put in the magic words SFP101N:

ebay

And so on and so on for page after page. It seems that is it not so hard to find after all… so long as you know what you are looking for. I ordered the cheapest one I could find, and it was delivered within a day or so – great service as always from ebay traders.

Having looked a bit more closely at the mechanism I have, I’ve now found I could have saved a lot of time because the head has ‘Sanyo SFP-101N’ moulded onto it – although in such a way that you need to look closely to see it. Never thought of looking though… d’oh.

This experience so far has made me reflect on what a wonderful thing the Internet is – here is a fairly old and obscure CD player with a faulty component – and after a couple of hours searching I have identified the part needed and ordered it and within less that 48hrs it is in my hand. One could never have done such a thing a few years ago and the player would almost certainly have been consigned to the dustbin. Genuine Teac parts would have been expensive, and for a normal person like me, unobtainable.

The other thing which is interesting is that even the highly expensive professional products still seem to rely on absolutely bog standard hardware – I bet that the SFP101N is used right across the board.

I’ll describe the installation in the next post… and after all this it had better work!