The rotary voltage selector switch and transformer are damaged and have to be replaced. There was a little accident during testing which had to be fixed but things are looking up now. A replacement transformer has been ordered. For more details on progress, click here.
I have had a Hitachi TRQ-295R cassette recorder which stopped working from the mains in 1979. I always wanted to get round to looking into fixing it so after the best part of 36 years i started yesterday.
The rotary voltage selector switch and transformer are damaged and have to be replaced. There was a little accident during testing which had to be fixed but things are looking up now. A replacement transformer has been ordered. For more details on progress, click here.
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The greenhouse is now filled with seed trays on heated sand bed propagators or in electric propagators. As a result i will need to move some plants out into the house which i was trying to avoid. As in previous years i have decided to take the seeds that have yet to germinate off the sand beds and take them into the house and put them on an electric propagator. I will also set up the LED lights to try to speed up the germination. This will free up space on the heated sand beds in the greenhouse for small seedlings that can be brought on. The above pictures show the propagator trays on the heated sand beds and the electric propagators in the foreground on the left. It all looks a bit messy but is actually quite organised. It is after a production facility where i also have to perform the work. When the weather improves a little more towards the end of March(hopefully!) i will be able to clear out all the compost, tubers and plants that i am currently storing in the greenhouse to protect them.
I have taken the DIY propagator into the house to bring on some Begonia, Antirrhinum and Cinerania. While it is there i plan to perform an upgrade to allow the overheard LED lights to be powered from it as it has a transformer built into it which can easily handle this additional load. This will reduce the amount of wiring and power supplies that need to be connected to run the propagators and lighting both in the house and the greenhouse. Completed work on testing the Extender Board and I/O board with the ZX81. The board burst into life after just less than 60 minutes of testing and repairs and it appears that the problem was that the chips had been put into the wrong sockets at some point over 30 years ago. Of course i did not have the edge connector then so never found that out at the time! At least it was easily rectified. If the chips had been damaged due to being in the wrong sockets i did have a few spares that i could have used. Successfully ran a small test program to confirm all the outputs of Port B of the 8255 could be toggled. Click here for more details. I had a spare hour so i used the time to solder the modified edge connector to the extender board. The pins bent quite easily down into position and made good contact with the circuit board fingers. The alignment of the edge connector and circuit board were checked with the rear connector of the ZX81. For more information click here. The French Marigold seeds were planted at lunch time on 16th March. This morning, the 19th March there were signs of 15 of the 60 cells having germinated. Some just showing through the soil and others having broken through and trying to open their leaves. The heated sand bed is definitely doing a good job with the Marigolds as it has in previous years. I plan to use the LED lights on the Marigolds in the greenhouse to try to bring them on a little quicker as the LED lights worked well with the begonia seeds and tomatoes in the house during early February when the sun light levels were poor. Thinned out the Begonia Destiny and Impatiens seedlings into individual cell trays. One tray of Begonia's produced over 160 small plants. The impatiens seeds had developed very well although as i said in a previous post the germination rate of the seeds was lower than i had hoped. I suspect this is because the seeds did not go through a process of 'stratification' because i accidentally stored them in the house after collecting them. In short this means that the seeds did not got through a period of 3-6weeks of cold during the winter. It is common for germination rates to be lower in seeds which have not experienced a period of winter cold.
I have planted a half sized tray with more impatiens seeds to increase the number i will have available in 6 -8 weeks when it will be time to start planting out in the garden.
I decided to soak the seed trays after planting rather than top spraying the compost to minimise the amount of spray that lands on the leaves and stems which can lead to damage when the sun is strong and can encourage the growth of fungus. I left the seed trays to soak until the top surface of the compost was moist which ensured the roots were well soaked. Any excess water drained out when the trays were placed on the heated sand bed. Started work on modifying the connector for the ZX81 Extender Board. Modifying the connector took 30 minutes and is now ready to be soldered to the extender board. Click here for more details. I collected the ZX81 edge connectors from Maplin Electronics today. I plan to install them in the next couple of days, set up the extender board with the I/O board and then perform the big switch on!
I will post a couple of photographs of the edge connectors before and after they have been modified(cut down to the correct size) in the next few days. Continued planting seeds in the green house and putting them on the heated sand beds. Planted Begonia's('Tom Foolery'), Petunia ('Multiflora F1'), Antirrhinum, Impatiens and Some more French Marigold('Boy O Boy').
The Begonia('Tom Foolery'), Impatiens and French Marigold('Boy O Boy') seeds were all collected from plants last year so it will be interesting to see how they develop. The Begonia('Destiny') and Impatiens seeds that were planted in late January and are doing very well were germinated from seeds collected from last years plants so i am hopeful that this second batch will also do as well. I checked the outside tap, lubricating all the seals and re-installed it this afternoon.When the water was turned on in the house again there were no leaks so that's a good start to the season. Unless the weather takes a really nasty turn for the worse the risk of freezing pipes should be past by now. I also cleaned and lubricated all the valves and moving parts of the manifold which will be re-installed on its mounting tomorrow, weather permitting. The tomato and aubergine seedlings are developing well, the tomato seedlings are developing a little too quickly and i do not have the space to store them so i will need to find new owners for them in the near future. After being away on business for two weeks it was time to get started in the greenhouse. The seedlings in the propagator started in the house have done well on the propagators in the greenhouse and it is now time to thin these out and start other plants from seed on the propagators. Over the past couple of years i have started too many plants at the same time which has made housing them all at the same stage difficult so this year i have planned two possibly three waves of plants. If all goes to plan i should have seeds germinating, thinned out seedlings and young plants ready to be hardened off by the middle of April.
The heated sand beds were set up today and 4x60 cell trays filled with compost placed on the beds ready for seeds. The remaining tomato seedlings have been transplanted into individual pots. The French Marigold('Boy-O-Boy' type) seeds have been planted into 60 cell trays and placed on the heated sand beds. The Marigold seeds should germinate within 5 days on the heated sand bed. The Fuchsia's have started to grow again with new leaves just developing. These have been moved out into the mini greenhouse to create some space in the greenhouse. I will add further insulation to the mini greenhouse to protect the plants from frost. The Fuchsia's that have not shown any sign of growing yet have been re-potted to bigger pots and placed on the heated sand bed to try to kick start them. Interestingly they are all the 'Marinka' type. Two trays of Begonia('Destiny') tubers were planted into compost and placed on the heated sand beds with propagator covers. The tubers will probably take about 10-14 days before there are any signs of shoots developing. The important thing with the Begonia tubers is to keep the compost moist and the humidity level high to bring them out of dormancy as quickly as possible. |
AuthorAllan Faulds is an Electronic Design Engineer who develops Hardware and Software on a professional basis. He has a strong interest in applying his design and development skills to his areas of interest such as bicycle lighting and plant growing and greenhouse and garden control technology. Archives
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