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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment. |
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9th Jun 2011, 6:39 pm | #1 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Dog House PSU
Any one ever replaced the mains tranny in one of these with an equivalet (the original is potted)
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9th Jun 2011, 7:53 pm | #2 |
Retired Dormant Member
Join Date: Mar 2006
Location: Sheffield, South Yorkshire, UK.
Posts: 1,587
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Re: Dog House PSU
Hi,
Send a pm to Ed dinning, he may be able to make you a new transformer that is more reliable. They are notorious for not liking 240V and burning out, Ikeep mine on the 110v setting and feed it from a 240/110V isolating transformer. Mike |
9th Jun 2011, 8:22 pm | #3 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Dog House PSU
Thanks Mike, yes they don't like it for some reason, I have had a couple of them go over the years and strangely in both cases the receivers worked as normal while the Pitch was boiling over the top of the potting container, the last one I had go only boiled the other week, I had the receiver on and working and was listening to DX up on 40, the first thing to notice was the smell, so with the set still working I CAREFULLY whipped the cover off the PSU the stuff was bubbling well by then. I checked the mains in and that was fine, all secondaries were fine including the current draw from the receiver. switched all off and checked the primary and secondary resistances, they seemed about right for that size of transformer. A shorted turn I guess.
I will obtain a better replacement at some point then with the old one I will short out all the secondary turns with connector blocks, short the mains fuse in the plug, take outside and plug in 'till the pitch goes liquid and tip the contents onto the lawn, don't try this at home folks (we never did this in City & Guilds practical!) Lawrence. |
9th Jun 2011, 11:47 pm | #4 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,527
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Re: Dog House PSU
I wonder if it's 240V they don't like, or 50Hz. A marginal 60Hz design will have a higher magnetizing current on 50Hz. This can result in more resistive losses or worse- pushing the core into saturation on current peaks, resulting in even higher losses.
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10th Jun 2011, 12:35 pm | #5 |
Heptode
Join Date: Apr 2010
Location: West Midlands, UK.
Posts: 659
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Re: Dog House PSU
Herald1360 has a point here. I have had quite a few transformer failures on US gear, such as Hallicrafters and RME receivers, also in a Philco domestic set run on 110 volts, a 16 % reduction in frequency is quite an amount for transformer designs which may have been a bit marginal originally. The Dog House supply I have been using is still working but buzzes a lot and gets quite warm.
Regards, Mike. |
10th Jun 2011, 5:37 pm | #6 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Dog House PSU
Yes I am in agreement with you all, it's murphys law but I butchered a home brew valved stabalised supply the other day for some bits, I should have kept it, I will knock another one up somtime and use that instead.
I will keep any original seperate PSU's for showing off purposes only and quick fire ups, it's a bit like taking a shower with your mac on but in the interests of preservation I think I will take that option. Lawrence. |