Overheated chip?

[drgj]

I bought a Bachmann loco fitted with a dcc chip. As I use DC only I thought I could sell the chip to get a little money back. However, for the second time I have received a loco with a chip that looks like this. the back has a black blister but the front looks ok. The chap didn't say it wasn't working on dcc but I can hardly sell it like this. I can't test it on dcc, of course. Anyone else come across this? I'm not too bothered about sending it back because I am pleased with the loco otherwise although there are a few repairs to make as usual!

[Tricky Dicky]

Someone who is familiar with this decoder might be able to confirm or deny this but that looks like a customized integrated circuit not a blister. Components like this are often seen in space critical situations such as circuits in musical greeting cards.

 

Richard

[Crosland]

You can see on the top side that there is no processor chip to provide the decoder functions. It uses "chip on board" assembly and the naked silicon is attached to the PCB, on the back in this case. The black blob is a protective layer.

 

Andrew

[drgj]

Thanks for the two replies. So it is probably ok? That's good. I threw the other one away, unfortunately! What a waste.

 

Dave

[tractor_37260]

Looks like a Bachmann (ESU Lokpilot) 36-553 decoder   The 21pin version 36-554 also has this distinctive "bulge" 

[drgj]

Thanks for that, Tractor.

 

dave