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I am restoring a Pioneer Elite VSX-81TXV with water damage? (perhaps salt water? Because it seemed very corrosive and left white residue on PCB etc). Either way whatever it was it has corroded a lot of solder (thankfully most of it is just surface corrosion), however there is one part which has such tiny legs that the water seemed to have eaten through 2 of the 6 legs. (and yes I will reflow the solder on many joints later, but right now I am cleaning it and getting corrosion off). Also it does partially work - just has no sound outputting - I had it work once a few years ago. But it won’t work now so I took it all part to locate the issue (Which all looks like it’s just broken solder joints other than this one IC). And the legs where there they just fell off when I went to clean it - there was about a 1/3 of the legs left.
Can anyone identify this so I can order a replacement (or if it’s not available then perhaps the parts needed to build an emulated version out of other components)
Attached is a photo and the service manual page with this Q701 with marking “D2”
The Service Manual is easy to find if you search “Pioneer 81TXV service manual”
This looks like a level shifting device. It converts a ground referenced signal to +7 or -7 VDC. This is then used as a control signal for the Toshiba TC4066 analog switch.
Based on the schematic part number of UMD2N, I believe this Rohm part may be a valid substitution.
Before purchasing:
please verify the IC package by comparing the physical measurements to the datasheet. This is important as there are several closely related packages as show in in this datasheet.
follow the circuit traces and compare them to the datasheet. Specifically, the junction collector of Q701 (C2) and pin 5 of the TC4066. Once again, there are several closely related devices with slightly different pin configurations.
Kindly let us know if you were able to restore the receiver,
Well it defiantly looks like the “SOT-363 UMD2N EMT6 (UMT6)” based on listed in the 3 options.
Digikey lists 5 matches of the UMD2N with various endings/#/letters… all of them seem to list the same specs save for one that lists the VCe Saturation as 100mv vs the others at 300mv. (So I am not sure what all these other letter/numbers mean at the end of the part #)
But, it looks like the one you linked might be the best match!
From the datasheet of the Rohm EMD2 / UMD2N / IMD2A, the part marking for all three variants (different package sizes) is “D2”, which, along with the part numbering in the schematic, pretty much guarantees this is the right part.
Presumably, it is the SOT-363, based on the part number in the schematic, but you can verify by studying the package dimensions on pages 7-9 of the datasheet.
