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Previous board repair appeared to swap TD62064AP for TD62064APG. Should I swap?

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So I have a "Densha De Go!" arcade cabinet and I have come to find that a critical indicator light (0.3 amp 12V Incandescent Bulb) is not illuminating when commanded. Testing revealed that the negative wire was sat, but I get nothing on the 12V+ wire. (I had this wrong, the NEGATIVE wire is the dead one) Tracing it back to the board sets I narrowed it down to a specific PCB. (I am unable to find any repair manuals or schematics as everything is in Japanese, so I'm sort of winging it here.) Anyway, I believe I am on the right board... I started inspecting for failures and came across a TD62064APG that had clearly been swapped out as I see some solder blobs and naked pins. My first urge was to repair the solder job, but I have a few things I am unsure about...

First, am I correct in assuming that you would use this IC to drive a low voltage lamp, and am in the right area?

Second, it appears that the "G version of this IC is quite similar to the original version, and looking at the datasheets I'm not sure what the difference even is... My first instinct is to find the original IC and replace this with a new one to ensure that this one isn't fried, fix the missing solder, and have the original part number in there, just to be extra safe.


(Thanks BTW)

The "G" version si exactly the same as the non-G, except it's lead-free. This might explain the bad soldering job.

Ah, that makes sense. Thank you.

As for replacing it, I see that they are EOL. I have always replaced components with the exact same model in the past. I can find them on eBay but am worried about authenticity. I also see there are similar options currently in production from other manufacturers like ULN2064B. Should I just get one of those from a legitimate supplier or what?

Thanks again.

You need to prove IC81 is faulty, not just jump to it because its been (badly) resoldered.  Trace the faulty lamp circuit all the way back to the specific pin of the specific driver IC.  If its not IC81, you are barking up the wrong tree.   If it is, use its datasheet to locate the corresponding input pin and see if its getting a drive signal. 

As others have said I'd almost certainly start by fixing the botched soldering job.    It looks like the last hack didn't even bother to solder some pins (maybe they are not used) but the whole job leaves me thinking that the old solder job itself may be a problem.   

As for actual chip replacement I also believe that you should verify that it has actually failed.   That is verify the state of both inputs and outputs.   With chip replacement you always run the chance of board damage, so random replacement of IC's should not be avoided.    This isn't at all like the repair of decades old equipment with dodgy capacitors.


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