Neo Geo CD dead Inductor replacement

hi members , im thinking of buying some non working Neo Geo CD units and fixing them up and keeping them


one thing that can go wrong with them is a ' Inductor ' dies and needs to be replaced , im looking for a suitable replacement


some of the Inductors in the Neo Geo CD have this Band Code


Yellow , Brown , Black , Silver



if i can find a suitable replacement for the above Inductor and theres anymore Inductors with a different Band Code i should be able to find replacements on my own



also when the Yellow , Brown , Black , Silver Inductor is identified i need to find sources to buy them from so ill need some help with that also




chat soon

 

That's 41uH, 10% tolerance, assuming it's using the EIA 4 band color code - but that's not really enough information to identify a replacement...

Edit:

I realized that might come over as a smart-ass comment, although it really wasn't intended as such. The thing is that inductors have quite a few other parameters, such as DC resistance, saturation current, Q, ... - and which ones of them are or are not important will vary depending on where it's being used in the circuit. You can also sometimes infer some of this information from the appearance, so a photo of the board with the part identified would be useful.

Failing that, you could probably work it out from the position in the circuit - a filter for something like a video buffer is going to pull a lot less current than the CD assembly does.

 

hi TriMesh your first response was great i didnt get offended.............


below is a pic of the board , theres 3 in this shot one right at the top and 2 at the bottom..............the bottom one at the left is the defective one


i dont know if this will help but when probed the Inductor on the bottom right gives 4.96V

 

OK - my guess is that it's just a supply filter, so nothing especially critical about the spec. Looking at the board layout, I assume it's providing the power to the video encoder chip, probably a CXA1645 or something similar (the one on the lower right looks like it's running the audio DAC). In this case, the fault would be a complete lack of video output - is that what's happening?

Can you take a photo of the trace side of the board, too?

Edit:

OK, that looks like the same board from here:

https://wiki.neogeodev.org/images/e/e1/Neocda41.jpg

And in that case the video encoder is indeed a CXA1645. According to the datasheet, it has split supply rails and takes less than 50mA across both of them.

41uH seems to be a strange value by current standards, so it's hard to find - but since the value is not that critical in a power filter position, you can use a 47uH, which is a very common value and gives you a wide range of parts to choose from.

I just had a quick look on Digikey, and this looks to be a reasonable replacment - it's also rated at 205mA current, so should have no problem running the encoder chip.

http://www.digikey.com/product-detail/en/78F470J-RC/M10141-ND/1305999

 

wow what an amazing response !

thats right its a CXA1645 to be exact its a CXA1645P , and yes the Youtube user was getting no video so he did some probing with a DMM and found a dead Inductor he then bridged the legs with a pair of tweezers and video was restored.



really impressive work TriMesh with little to go by and to come up with your response is really stunning ..................



this has helped me alot and im thankful for everything


chat soon

 

Thanks for the kudos - but it wasn't really that difficult in this specific case. There aren't that many RGB capable video encoder chips, and that 400mil (0.4") wide 24 pin package is a quite unusual one, so it wasn't a hard guess to make. On top of this, the board was laid out in clearly defined sections with those white lines on the silkscreen separating the areas - and if you look at the left end of that inductor you can see a pair of caps, one ceramic and one electrolytic, which is a typical arrangement for supply decoupling.

I have to admit that I've spent rather a long time looking at PCBs, though