This thread is a bit like:
"My head hurts. Could someone explain how to do brain surgery?"
"Oh, that sounds complicated. I have a penknife and an electric drill. Couldn't I just cut out the bit that hurts then stuff the rest back in?"
"OK, I will pay a surgeon to do it instead. Who would have thought that brain surgery could be so complicated?"
"My head hurts. Could someone explain how to do brain surgery?"
"Oh, that sounds complicated. I have a penknife and an electric drill. Couldn't I just cut out the bit that hurts then stuff the rest back in?"
"OK, I will pay a surgeon to do it instead. Who would have thought that brain surgery could be so complicated?"
The motivation for DIY anything is to save costs and maybe explore and gain a little learning about technology and the world of manufacturing. Still, it amazes me how little basic research is done by members before their intentions are announced and questions asked here.
It's no surprise that Google and other worthwhile search engines are wonderful finders of good (and also foolish) advice on just about any imaginable topic including small transformer repairs. A little thought about even the style of a reply is usually enough to discern the difference, even if you don't understand the topic. On a quick scan, this came up as a similar query with detailed replies: https://www.electronicspoint.com/threads/toroidal-transformer-repair-possible.52738/.
It's no surprise that Google and other worthwhile search engines are wonderful finders of good (and also foolish) advice on just about any imaginable topic including small transformer repairs. A little thought about even the style of a reply is usually enough to discern the difference, even if you don't understand the topic. On a quick scan, this came up as a similar query with detailed replies: https://www.electronicspoint.com/threads/toroidal-transformer-repair-possible.52738/.
I suppose any motor/alternator rebuild shop could rewind a transformer. But why? You *will* pay "retail on retail" prices (sort of like speaker reconing). Either you *can* do it yourself, or you don't mess with it. If you don't know what you're dong that falls out of the realm of "can".
Bobbin style trafos are not that hard to rewind. But I wouldn't touch rewinding a primary. Bad primary you just pitch it, or unwind it and save the wire for speaker crossover coils. But I've put plenty of new secondaries on to make what I need out of what I have. Toroids are even easier - you do need a winding jig which is easy to make. i'll buy what I can get cheap, and put whatever secondary I want on there. Biggest expense is typically the magnet wire and you really want to use new. Toroid.com has pre-wound primaries available if you need something atypical, but I usually get mine from the surplus market.
Bobbin style trafos are not that hard to rewind. But I wouldn't touch rewinding a primary. Bad primary you just pitch it, or unwind it and save the wire for speaker crossover coils. But I've put plenty of new secondaries on to make what I need out of what I have. Toroids are even easier - you do need a winding jig which is easy to make. i'll buy what I can get cheap, and put whatever secondary I want on there. Biggest expense is typically the magnet wire and you really want to use new. Toroid.com has pre-wound primaries available if you need something atypical, but I usually get mine from the surplus market.
If cost is not critical, any local manufacturer of small custom transformers should be able to undertake the rewinding of conventional or toroidal types, given you have the winding specification, including any screen or gauss band, lead lengths and mounting method etc. plus the old core. I have read and experienced that custom builds cost about 3-4 times the off-the-shelf cheap import price of a similar toroidal type and a full rewind will surely be in that category.
So, you may find a similarly rated and featured transformer in your usual distributor's catalogue for $100 but then think of ~ $400 as your budget price point
So, you may find a similarly rated and featured transformer in your usual distributor's catalogue for $100 but then think of ~ $400 as your budget price point
The reason we have transformers rewound is because in some cases, there isn't an off the shelf replacement available.
Transformer rewinding is a specialized field requiring specialized equipment and dedicated work space.
I once tried to disassemble the core of a burned out transformer, but soon realized I didn't have the tools nor the expertise to split apart a core that was packed tightly. I'll admit it would be a useful skill, but save that for the youngsters. I focus on vacuum tube circuits; it's what I know and what my shop is equipped for. I leave the rewinding to others.
We used to get transformers rewound at about $250 each.
Transformer rewinding is a specialized field requiring specialized equipment and dedicated work space.
I once tried to disassemble the core of a burned out transformer, but soon realized I didn't have the tools nor the expertise to split apart a core that was packed tightly. I'll admit it would be a useful skill, but save that for the youngsters. I focus on vacuum tube circuits; it's what I know and what my shop is equipped for. I leave the rewinding to others.
We used to get transformers rewound at about $250 each.
What´s best in USA/Canada/UK/Japan is not necessarily best option in, say, Philippines, Argentina, Brazil, India or even Poland , Ukraine or Russia.
In USA you have lots of off the shelf ready built stuff at all kinds of prices, including very inexpensive ones (thanks, Comrade Deng Xiaoping ) , plus high hourly cost for any specialized work, so buying ready made is the sensible option.
Not the same in other Countries, where repairing, (rewinding in this case), plus local availability vs. expensive freight, Customs barriers (including tariff) and waste of time, make repair the best option.
In USA you have lots of off the shelf ready built stuff at all kinds of prices, including very inexpensive ones (thanks, Comrade Deng Xiaoping
) , plus high hourly cost for any specialized work, so buying ready made is the sensible option.Not the same in other Countries, where repairing, (rewinding in this case), plus local availability vs. expensive freight, Customs barriers (including tariff) and waste of time, make repair the best option.
Understood about the challenges faced in other countries. However, some vintage gear utilize transformers with unusual types of windings, and are not found as ready made manufactured parts today. The other issue is that even if you do find a match, electrically, the new part may not fit the layout/hole spacing on the chassis. And the replacement part often costs more than the rewind.
If you still want to rewind the traffo, then visit http://www.diyaudio.com/forums/analogue-source/292628-high-audio-quality-am-tuner.html post #100, there you can see how I did it.
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