Sharp Optonica SM-4100 Schematic

I have one! Found the old paper copy from a very long time ago, and for the benefit of those out there in InternetLand, I have posted a copy of it in jpg format.

Go to this link for the big version --> SM-4100 Schematic

Repaired my biiig Plasma TV

I was gutted when my lovely plasma TV decided to die. It was only the video inputs that went - I could still get some things on the screen like the volume control. So, on the offchance, I went on that auction site again and looked for a new digital board for it.

Well, I was surprised to find a TH42PZ70BA digital board for 13 quid.

After removing what seemed like a million screws, I got down to the point where I could actually see the board I was trying to replace ..

 

I was even more shocked when the replacement worked - all back to normal again! 

This is probably the last time in my life I will ever repair a TV, I just thought. I grew up with mono TVs and new colour TVs with their tube output push-pull output stages (Philips G6), LOPTs and triplers and CRTs with rimbands, convergence with 22 pots to adjust and a ton of X-rays shooting out. I used to help repair TVs (and amps, receivers, tuners etc) for pin money as a student. TVs were most challenging since the focus voltage was a few thousand volts, and the EHT was 25KV. Quite scary to work on the things, and the dust would collect on the high voltage components. I used that as an indication on the neck hardware which pins to avoid touching (all of them).

Interestingly enough I had to apply a vacuum cleaner to this Plasma before I could repair it, as it was just coated in dust. 

These days, I do repair the odd LCD but they are very uninteresting. Occasionally it's a power supply capacitor that has let go. Sometimes that takes a switching transistor with it. Most other faults though, including the mechanical stuff - broken screens, broken connectors - I am sorry, but it's easier, faster and cheaper to go buy a new one. It rankles a bit, and offends my sense of wanting to repair rather than replace, and my care for the environment. When did manufacturers give up on designing things for repair? Well, if the plasma is anything to go by, about ten years ago.

Virgin Media delivers ...

(I have no affiliation with etc etc .. only commercial interest is if you are thinking of switching, let me recommend you and I will get a discount off my next bill) ..

After a bit of to-and-fro with Virgin Media, and a few days of suffering dropouts every couple of hours, I have a new Superhub 3 installed and the latest broadband package - at 20 quid a month less than I was paying .. 

I ran Speedtest ..

.. And in the meantime I thought it a good idea to buy a little runaround ..

So I am working on the big girl. I have it in mind to do a bob/rat/chop on her .. she is mechanically very sound (probably needs the clutch sorting out along with the brakes needing a rebuild, new air filter, oil filter, new tyres, seized fuel tap, seized choke, seized throttle cables, switchgear needs sorting out, new sprockets and chain, rusty frame needs sorting out and the seat needs recovering and repadding. Front headlight is rusted out on the rim, and the front mudguard is cracked. The battery is long dead. The front handlebar bar ends are rusted out to where I am not sure it will be possible to get new grips on her).

My vision statement for her is something like this ..

 

 She is a bit of a pig at the moment though, lots of bolts shearing and so on. I did get the exhaust off, but one stud snapped, so I will have to borrow / buy EasyOffs to get the stud out. I like the wrapped look as the picture above .. the wrap comes from China, and is not too expensive.  I like the idea of a matt or satin black frame where it needs repainting, satin black wheels and spokes, whitewall tyres, creamy white paint job on bobbed mudguards and tank, with an airbrushed orange edging. WS2812B LED strings around to pick out the lines of the bike at night - default colour orange again, but hey! what would be the point of WS2812 without a microcontroller doing some fancy lighting patterns.

So, it's going to take a little longer to sort out the old girl than I hoped. I might make some good progress in August - anyway, it gives a window of time where I am not driving a car, and I am now working across a few of the NHS Trusts in the South. The car parking is outrageous at hospitals, and it is no better for visiting staff. It's not much better for permanent staff - they might let you park in the park and ride for a fee (!). I'm also over on the other Island quite a bit, so I thought it would be a good idea to get a little runny around kind of bike in the meantime. She was cheap, so there are some bits to tidy up. The grips need replacing, the sprockets and chain were well beyond sell-by date, the rubbers on the pegs are worn. But she starts first time, which is one of the the major requirements of a commuter bike. 

 

I've got some new grips on order from China, and very pleased with the gold chain and replacement sprockets. 

Might have to replace those shocks and springs sometime - they look a little shabby. But then I am in danger of spending more time and money on the little runaround that keeps me on the road, when I should be spending money on the big girl.

Fooze that bike!

I've decided that this is the year to get my bike back on the road. It's in a bit of a sorry state, but nothing that a few tens of hours with sandpaper, primer and paint won't sort out. I need a bit of a something to get my teeth into that isn't just electronics.

The bike used to look like this when it was new 16 years ago:

I hope to to something a bit different with it, and get it on the road again this year. It would be fun to get over to the Island on it! and I should be spending a couple of days a week there this year for the project I am working on at St Mary's.

.. and we are live with Asterisk!

I solved the issue with the analogue phone lines by getting rid of them. For the princely sum of 5.95 per month, Sipgate offer a trunking service, which means you can get your Virgin Media provided phone number transferred to them, and they will forward all calls to that number back to your own Asterisk system.

I've not done anything too complex so far, but it all works. If someone calls, then the VoIP phones (the Cisco ones) ring - first the main ones, then if they aren't answered the ones in the office and craft room get added on, and then if they are not answered, the mobiles ring!

If the call drops through to voicemail, the message is sent via an email attachment to us, so we can pick it up on our mobiles wherever we are as well.

Now Virgin Media charged me 17.95 a month for the privilege of a phone line. Since I don't need that any more, I wonder what their reaction will be when I ask that I have that money taken off my bill?  (Please note this only works if your current provider doesn't use the phone line to provide your broadband. Obvious when you think about it!)

All bets taken. Mine is that I might get a discount of a fiver after months of haggling.

*** Wrong again. After haggling, VM tell me that it is actually more expensive to change package to stop paying the line rental than it is to keep it. We need a bit more OFCOM legislation I feel. 

Asterisk and stuff

One of the other fascinations I have is with telephone systems. I have a Cisco 7940, and a 7970 in the house, and I have a Sipgate account for VoIP. It was working fine with one phone, but then I thought I wanted both phones working. SIP is a strange protocol, and is hugely flexible so you can spend happy hours playing with all kinds of things to get it going. The phones are different as well; Cisco rely on having a TFTP server in the network for the phone to boot from, which contains most of the phone configuration. Each phone has a SIP<macaddress>.cnf file in the tftpboot directory that it looks for, to bring up the phone. I had some happy times with Wireshark to find out what was going wrong. Having fixed the 7940, the 7970 uses a similar approach, but a completely different format for the configuration file - now in XML! The phones also have their own web services built in ..

So having the phones working individually, I needed something so I can use them both. There is a lovely bit of Open Source software - Asterisk - that can run on Linux to provide a local PBX solution. So, downloaded that, and it now functions to manage calls coming in and going out on the SIP line.

I then installed Zoiper on all of the mobiles and tablets in the house, and that works well - so I can now call Trish from the office to her mobile, without the call going out over the air - and therefore is free. So far so good.

What I want to do next is to receive incoming calls on the house phone, and send them out to the SIP phones. So, how to solve this?

I did the usual, searched with Google and decided from a ten minute bit of research that the SPA-3000 device, available for pennies from eBay would be a good bet. Ah. Now the real fun begins.

I found the manual online, and there is a very comprehensive Asterisk book for download. I am still struggling though - this is a key part of the home phone strategy, so I can use the existing analogue handsets over DECT to ring them (assuming the phone call is from someone I like - telemarketers will get a very long message advising them that we don't accept unsolicited marketing blah blah on the phone). I will post more as I find out more, but this is a nightmare so far. There are literally hundreds of settings for the SPA-3000.

I may have to sell the little darling and buy a better interface.