Sansui AU-D907/AU919 Blown Transistor
- Thread starter RichardR
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Firstly, you might be able to buy 'used' NMA/NMC devices from auction sites, but you run the risk of buying damaged transistors. The originals haven't been made for decades, and it is suspected they were specially made for Sansui only. There are no devices available new, with a matching case style that are adequate substitutes for the originals. You can buy transistors like this that will work, i.e. MJ21193G (PNP) / MJ21194G (NPN), but because the originals are so special, you will have lost some of the superb sonic performance that the originals are thought to give. So in effect, fitting these will get the amplifier working again, but with degraded performance. The driver transistor 2SB537 is quite a lot easier to replace with a substitute, but is also recommended to be replaced with its complementary device in both channels, thus replacing all the driver transistors. Replacements could be 2SC4883A/2SA1859A or similar - these devices are currently available from reputable suppliers like Mouser or Digikey.
So the solution most use is to discard all of the originals and fit TO-3P case style replacements, how easy this is depends on the design of the heatsinks, and your skill working in the electronics and mechanical sense to get the replacements installed.
Check out this thread, especially from post #83 onwards on how to do this.
https://audiokarma.org/forums/index.php?threads/ba-f1-restore.798969/
Overall if you are a novice, you should seriously consider the wisdom of doing this yourself as getting it right, with no mistakes is a very tall mountain to climb.
So the solution most use is to discard all of the originals and fit TO-3P case style replacements, how easy this is depends on the design of the heatsinks, and your skill working in the electronics and mechanical sense to get the replacements installed.
Check out this thread, especially from post #83 onwards on how to do this.
https://audiokarma.org/forums/index.php?threads/ba-f1-restore.798969/
Overall if you are a novice, you should seriously consider the wisdom of doing this yourself as getting it right, with no mistakes is a very tall mountain to climb.
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Hello guys, I am looking for the service manual of a Sansui AU-D907 (Japanese version). I've got a copy of the service manual for the AU 919 but unfortunately my technician says they are different and is unable to perform a repair in the amp. Do you know where can I get the AU-D907 manual from? That would be greatly appreciated!
Great. Done that already. Unfortunately I don't seem to find an option to delete my comment in this post.
frend2001
Active Member
Well....with the help of our Sansui veteran Guruji (Hyperion), I have been able to address blown transistors in my AU D707 ( AU 819 internationally ). I have used Sanken MN1526 / MP1526 to replace NMA/NMC 1216 in my unit. Theses are TO-3P devices and with little maneuver my tech had been able to fit them in.
The SQ is almost there. So please look up the ways the TO-3P devices were adopted to fit into TO-3 sockets. It more or less looks a tad too much jugad (Indian Slang for makeshift) but It's been working on my unit since almost a year now.
Hope this helps.
The SQ is almost there. So please look up the ways the TO-3P devices were adopted to fit into TO-3 sockets. It more or less looks a tad too much jugad (Indian Slang for makeshift) but It's been working on my unit since almost a year now.
Hope this helps.