07-10-2012, 09:20 AM
Thanks for a most interesting and eclectic post Nick.
The UFO is an amazing bit of kit - highly convincing. UFOs are just that - flying objects which remain unidentifed until their identity is established. In the case of Mike's 'UFO' once its identity is established, it ceases to be a' UFO' and becomes a 'FO! I hadn't realised that Mike's activites were so varied and high level. Where do such people (you included!) find the time? Your uDRSSTC project must have involved a great of development - nice double sided PTH PCB! Even sourcing components can be quite a challenge these days.
As to your DAC90A project, DAC90As do evoke different views and emotions, rather like Marmite - you either love it or hate it. It has its fans, but it makes others want to reach for the the bucket! With me, it's a generational thing - I was nine when the DAC90A was put out on rental in its hundreds of thousands, and we had one stuck on the shelf throughout my teens until it packed in yet again (UL41), and was put out for the bin men. I always thought it was a miserable looking thing and was glad to see the back of it. When I see one now, it's just an echo of the past - years of post-war austerity, ration books, shoddy goods and make do and mend.
It won't evoke those feelings in others of course. Some consider them a thing of beauty and an icon of the late 1940s. (I've lost count of the number of times I've seen either Neville Chamberlin announcing that we we're at war with Germany, or Churchill in 1945 telling us that 'we may allow ourselves a few moments of rejoicing'!)
In the early 1970s I attended a year's evening classes on radio and TV servicing. The tutor ran his own shop and had repaired thousands of DAC90s over the years. His theory as to the design shortcomings was that the brief that Bush gave to the engineers was: 'Design a radio that works well, then progressively remove parts until it stops working, then put the last part back'. A bit flippant, it's true, but it won't have been far off the mark. It's design shortcomings are well known and much stated, but it's a fact at a time when most families could not have afforded to have bought a radio, rental companies favoured them and put them out in their untold thousands.
One of its plus points - which we forget these days, when we can afford radios in every room - is that it was 'transportable' within the home, but it wasn't unique in that. It didn't need an aerial so could be taken from room to room. (You didn't even need a power socket - just stick an adaptor in the light socket for the bulb and the radio!).
I understand that after several years, Radio Rentals et al told customers they would no longer repair them and that customers could buy the set if they wished for ten shillings. I suppose that's why so many still survive - they got put up in the loft when the UL41 gave up the ghost, to emerge decades late and end up at car boot sale or on e-bay. At least they have the merit of not getting infested with woodworm!
There are two sellers on e-bay who restore them and bring them up to standard. (Remove the dangerous mains connector and fit a three core non reversible flex, using the earth to earth the metal speaker grile, improve the dial lights, replace the caps, test and give a one year warranty). One of those restorers recently sold two sets - one at £225, the other at £285. The mind boggles, but it does show that reliability and safety triumph over originality in the minds buyers. The DAC90A is so commonplace that originality is an irrrelvance. Yet people will still pay upwards of £15.00 on e-bay for a two-pin mains socket. (One of the restorers fits a 6.3V transforer for the dial lights).
Your DAC90A nut and bolt strip-down and rebuild (a-la kaylee) has certainly set a few tongues wagging Nick, but you've shown how such things should be done - carefully designed layout, ultrasonic cleaning of switches, tuning cap etc. Beats sticking it in the dishwasher, as some have advocated, (or as I did in 1959, shoving it in the dustbin)
Yours must be well on the way to completion!
Better sets were soon on the market, but I don't think any have the same popular appeal as the DAC90A. I'd nominate the Stella 105U of 1952, which I think is a more cheerful looking set. It has dial lights that are fit for purpose, a dial that can be easily seen, and performs better, though has a slightly higher component count than the DAC90A. (37 caps/25 Rs, compared to 29/18 in the DAC90A. Admittedly it's a rat's nest beneath the chassis, which compares unfavourably with the DAC90A tagboard.
I dare say that anyone on the lookout for a DAC90A at a car boot sale would walk past a Stella 105U without giving it a second glance.
If I had to nominate a favourite small transportable set, I think it would be the Murphy U198 of 1954, and later, the Pye 'R33'.
Rambled and dribbled Yorkie.
(I used to work in a helium factory but I resigned - I'm not having people talk to me like that!).
The UFO is an amazing bit of kit - highly convincing. UFOs are just that - flying objects which remain unidentifed until their identity is established. In the case of Mike's 'UFO' once its identity is established, it ceases to be a' UFO' and becomes a 'FO! I hadn't realised that Mike's activites were so varied and high level. Where do such people (you included!) find the time? Your uDRSSTC project must have involved a great of development - nice double sided PTH PCB! Even sourcing components can be quite a challenge these days.
As to your DAC90A project, DAC90As do evoke different views and emotions, rather like Marmite - you either love it or hate it. It has its fans, but it makes others want to reach for the the bucket! With me, it's a generational thing - I was nine when the DAC90A was put out on rental in its hundreds of thousands, and we had one stuck on the shelf throughout my teens until it packed in yet again (UL41), and was put out for the bin men. I always thought it was a miserable looking thing and was glad to see the back of it. When I see one now, it's just an echo of the past - years of post-war austerity, ration books, shoddy goods and make do and mend.
It won't evoke those feelings in others of course. Some consider them a thing of beauty and an icon of the late 1940s. (I've lost count of the number of times I've seen either Neville Chamberlin announcing that we we're at war with Germany, or Churchill in 1945 telling us that 'we may allow ourselves a few moments of rejoicing'!)
In the early 1970s I attended a year's evening classes on radio and TV servicing. The tutor ran his own shop and had repaired thousands of DAC90s over the years. His theory as to the design shortcomings was that the brief that Bush gave to the engineers was: 'Design a radio that works well, then progressively remove parts until it stops working, then put the last part back'. A bit flippant, it's true, but it won't have been far off the mark. It's design shortcomings are well known and much stated, but it's a fact at a time when most families could not have afforded to have bought a radio, rental companies favoured them and put them out in their untold thousands.
One of its plus points - which we forget these days, when we can afford radios in every room - is that it was 'transportable' within the home, but it wasn't unique in that. It didn't need an aerial so could be taken from room to room. (You didn't even need a power socket - just stick an adaptor in the light socket for the bulb and the radio!).
I understand that after several years, Radio Rentals et al told customers they would no longer repair them and that customers could buy the set if they wished for ten shillings. I suppose that's why so many still survive - they got put up in the loft when the UL41 gave up the ghost, to emerge decades late and end up at car boot sale or on e-bay. At least they have the merit of not getting infested with woodworm!
There are two sellers on e-bay who restore them and bring them up to standard. (Remove the dangerous mains connector and fit a three core non reversible flex, using the earth to earth the metal speaker grile, improve the dial lights, replace the caps, test and give a one year warranty). One of those restorers recently sold two sets - one at £225, the other at £285. The mind boggles, but it does show that reliability and safety triumph over originality in the minds buyers. The DAC90A is so commonplace that originality is an irrrelvance. Yet people will still pay upwards of £15.00 on e-bay for a two-pin mains socket. (One of the restorers fits a 6.3V transforer for the dial lights).
Your DAC90A nut and bolt strip-down and rebuild (a-la kaylee) has certainly set a few tongues wagging Nick, but you've shown how such things should be done - carefully designed layout, ultrasonic cleaning of switches, tuning cap etc. Beats sticking it in the dishwasher, as some have advocated, (or as I did in 1959, shoving it in the dustbin)
Yours must be well on the way to completion!
Better sets were soon on the market, but I don't think any have the same popular appeal as the DAC90A. I'd nominate the Stella 105U of 1952, which I think is a more cheerful looking set. It has dial lights that are fit for purpose, a dial that can be easily seen, and performs better, though has a slightly higher component count than the DAC90A. (37 caps/25 Rs, compared to 29/18 in the DAC90A. Admittedly it's a rat's nest beneath the chassis, which compares unfavourably with the DAC90A tagboard.
I dare say that anyone on the lookout for a DAC90A at a car boot sale would walk past a Stella 105U without giving it a second glance.
If I had to nominate a favourite small transportable set, I think it would be the Murphy U198 of 1954, and later, the Pye 'R33'.
Rambled and dribbled Yorkie.
(I used to work in a helium factory but I resigned - I'm not having people talk to me like that!).
Regards, David.
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
