Searching for transformer/rectifier like in photo

Thread Starter

beginnerdude

Joined Oct 10, 2022
11
Hello,

I have been searching everywhere online for this combo transformer rectifier with no luck. Where do I look for such a thing? It's pretty compact (about 6cmsX5cmX6cm, something of that order) . I do not know the right term for it either. Thanks for any lead! (I even wrote to the company, but I have not gotten any reply. It's been a week).

IMG_3620.JPG
 

Alec_t

Joined Sep 17, 2013
14,263
Welcome to AAC!
That looks like an uncommon proprietary combo. I doubt you'll find a replacement other than from the maker.
What is it part of?
Why do you think it's faulty?
 

Thread Starter

beginnerdude

Joined Oct 10, 2022
11
Hi, it's part of a bosch radio. One of the leads feeds a battery charging station and the other the radio itself.

I think it's faulty because the unit plugged in, blue blue outputs incorrect voltage (close to zero), and likewise with red red.

oh well
 

Ramussons

Joined May 3, 2013
1,396
Is the size critical? Else you can use a transformer with 15-0-15 and 12-0-12 windings with Full wave rectifiers, or
a 15 volt and 12 volt secondaries with bridge rectifiers.
 

Thread Starter

beginnerdude

Joined Oct 10, 2022
11
I guess that since I am ultimately trying to have fun by fixing this bosch radio, size does not matter too much. I will probably add two then!
 

Jerry-Hat-Trick

Joined Aug 31, 2022
536
How about replacing (externally) with a 19V laptop charger? They are inexpensive because so many are made, or you may already have an old one or more from old lapstops? They are typically good for 3A. Drop the output to 16.5V and 12V through two LM317s inside the radio.
 

MaxHeadRoom

Joined Jul 18, 2013
28,576
Measure the resistance of the supply pair. (blue-brown?), often a thermal fuse is placed in the primary winding,
If so remove the cover , you may be lucky if it close to the outer edge and accessible.
 

MaxHeadRoom

Joined Jul 18, 2013
28,576
Infinite so open circuit?
I would remove the case/covering and see if anything can be seen.
I have found some thermal fusing to be so buried in the winding it is almost impossible to replace it, easily, anyway! o_O
 

Thread Starter

beginnerdude

Joined Oct 10, 2022
11
By infinite, I mean that the windings are not touching each other, so good news on this front.

But why would there be a thermal fuse inside a transfo/rectifier? I mean, this Bosch is basically a radio, nothing that is supposed to get really hot at all...
 

Thread Starter

beginnerdude

Joined Oct 10, 2022
11
Yes, the two-color scheme is weird. I too thought it was mislabeled, but the voltage outputs are nil either way. Also, if the heat fuse is buried deep in the winding, what will be the point of replacing it if I am to "tear" the winding away?

Will open the thing tomorrow just for fun anyway :)
 

sagor

Joined Mar 10, 2019
902
Most thermal fuses are near the outside of the transformer, just buried under a couple wraps of insulating tape. It is easy to remove parts of the tape around the primary side of the core, to see if there is a thermal fuse.
I have had one transformer that blew such a fuse due to stress or aging, but not because of thermal issues. I replaced it with an external fuse and the device is still running fine years later...
The primary winding, if open (infinite resistance), suggests a internal thermal fuse is open. Sometimes a voltage bump will cause a surge in current, which blows that fuse.
 
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