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Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders. |
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18th Jun 2018, 11:36 am | #1 |
Hexode
Join Date: Mar 2008
Location: Bristol, UK.
Posts: 388
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Farnell E30/2 PSU transformer burn-up
Can anyone see a problem with replacing a burnt-up original transformer in my E30/2 with 2 toroidals of suitable output which will fit in the void left? The toroids would be flat, one on top of the other, secured to the back panel by a large nut and bolt, flat washer, rubber washer and whatever else it takes to secure them. Les.
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18th Jun 2018, 11:47 am | #2 |
Octode
Join Date: May 2016
Location: Oxfordshire/Bucks borders, UK.
Posts: 1,604
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Re: Farnell E30/2 PSU transformer burn-up
The only immediate issue is isolation.
__________________
Avometer, vintage Fluke and Marconi collector. Also interested in vintage Yaesu and KW. |
18th Jun 2018, 1:18 pm | #3 |
Dekatron
Join Date: Jun 2016
Location: London, UK.
Posts: 3,687
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Re: Farnell E30/2 PSU transformer burn-up
Cost might be an issue. If you don’t alresdy have them, two toroids might cost more than a new E30/2 at current prices!
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18th Jun 2018, 1:59 pm | #4 |
Hexode
Join Date: Mar 2008
Location: Bristol, UK.
Posts: 388
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Re: Farnell E30/2 PSU transformer burn-up
I have two suitable already, bought at what I thought to be a bargain price. So long as I insulate each from the other and both from the case (at the same time allowing for some degree of air circulation) are there any other things that can cause me trouble? The transformer that came with the PSU was burnt up when I got it but I think there was a short to one of the 2N3055 connections at the back. A degree of caution and in-line fuses will be used when I first power on.
Les |
18th Jun 2018, 2:25 pm | #5 |
Dekatron
Join Date: Jun 2016
Location: London, UK.
Posts: 3,687
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Re: Farnell E30/2 PSU transformer burn-up
Should be fine then. One thing to note is the E30 benefits from addition of a diode across the terminals and the pass transistor otherwise the load tends to blow the driver transistor if there’s a power failure or overload.
I rather like those little power supplies myself. |
18th Jun 2018, 7:20 pm | #6 |
Nonode
Join Date: Jan 2016
Location: Stafford, Staffs. UK.
Posts: 2,532
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Re: Farnell E30/2 PSU transformer burn-up
I'm sure you know, but just in case, make sure that one end of the bolt is isolated from the case (and will remain so if something gets put on top of the case etc) otherwise you have a nice low resistance single turn secondary.
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18th Jun 2018, 7:29 pm | #7 |
Hexode
Join Date: Feb 2014
Location: Southampton, Hampshire, UK.
Posts: 419
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Re: Farnell E30/2 PSU transformer burn-up
Depending on MCB rating and Type and where you catch the turn on cycle you can get enough surge to trip some MCB's with toriods. The ratings for this PSU's toriods might not put you in this region but if you do get a turn on trip then slow turn on might be required.
Pete |
18th Jun 2018, 10:23 pm | #8 |
Hexode
Join Date: Mar 2008
Location: Bristol, UK.
Posts: 388
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Re: Farnell E30/2 PSU transformer burn-up
Thanks for everyones advice. When I get round to doing the repairs I will post again. Les.
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