beeman Posted August 23, 2012 Share Posted August 23, 2012 Can anyone help with this query, Anyone know what the number/type of the surface mounted O/P 'transistors' are on Bachman 36-553 and 554 decoders. They have code numbers on them due to small size rather than the full No., 030s on the 553 and 037m & 037w on the 554. Having blown one or two through installation 'errors'. Have managed to transfer one to repair another, so wondered whether the component itself could be bought from electronics component suppliers etc.,. I found when the damaged component was removed after a decoder was shorting, the short disappeared and would work in one direction only,proving that the removed item was the culprit and u/s. This decoder, one 'direction' was used for a windmill. In another, managed to repair to OK working. Thanks in advance. Beeman. Link to post Share on other sites More sharing options...
AMJ Posted August 23, 2012 Share Posted August 23, 2012 As these are quite inexpensive I might cost more in time, effort and money to source the said items than to buy a new decoder. If it takes you an hour to remove the culprit then get a replacement and you may have used up two or more hours. Even at minimum wage this works out cheaper to buy a new decoder. Link to post Share on other sites More sharing options...
Suzie Posted August 23, 2012 Share Posted August 23, 2012 It will probably be quite tricky to identify the actual components, unless ESU is forthcoming with a circuit diagram. If it is possible to find out where the three legs are connected elsewhere it might help in identifying a suitable replacement. One of the legs should go to the motor, and another to the supply. It is where the third one goes that is more important to identify. If it has a series current limiting resistor it is probably a bipolar transistor, but if it goes directly to a pin on the microcontroller it will be a FET. Just then need to find something with the same package, pinout and similar current capability. Next time you have a working transistor removed, it might be worth measuring it on a transistor gain tester (most multimeters have this nowadays) if it is bipolar. Link to post Share on other sites More sharing options...
beeman Posted August 24, 2012 Author Share Posted August 24, 2012 As these are quite inexpensive I might cost more in time, effort and money to source the said items than to buy a new decoder. If it takes you an hour to remove the culprit then get a replacement and you may have used up two or more hours. Even at minimum wage this works out cheaper to buy a new decoder. Agreed, but as retired and time my own, satisfaction is obtained by succeeding if/where possible. But is not the whole of our hobby not cost effective when one takes in the number of hours spent and the 'value' of that achieved, unless one happens to be a 'professional' layout builder or repairs /weathering etc.?. In most cases the interest and satisfaction in ones efforts/achievements being the reward. Beeman. Link to post Share on other sites More sharing options...
mikeg Posted August 25, 2012 Share Posted August 25, 2012 I tried to find a small chip to replace one in a ROCO control unit and although the number was clear to read a search of electronic component catologues failed to find the item. There were numbers both sides of the one I wanted and on asking RS if they could get one they said it was not possible as the number refered to a single batch made for a manufacturer in Korea and this often happens with specialist electronic items, so I think it unlikely that you will be able to get the actual item, but if it is a transistor you will be able to get a similar type one rated for the use you want. regards mike g Link to post Share on other sites More sharing options...
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