I am now working on my little brother's Sony 5.1 receiver (after I have some confidence after having just repaired my Mom's Marantz 6.1 receiver with this forum's help), I found that both transistors on his right channel were dead and am now looking for the cheapest distributor of these parts. Anyone know where I can find a Sanken MN2488 and Sanken MP1620 for cheap with cheap shipping? Thanks.
I bought some off of Ebay from a distributor named "Activeparts." They were like $8 per pair plus $5 shipping... cheapest I've found. Auction .
And I replaced them in a Sony receiver I have and they seem to work fine. Also, make sure you check emitter resistors and the various resistors on the board. On mine half of the dual-emitter resistor on the channel needing new transistors was blown and a 680ohm resistor around the transistors was blown.... there was also a 10ohm resistor around the middle of the board which looks to have been replaced (well, actually just bypassed with another 10ohm resistor) when I bought it broken off of Ebay. Good luck!
And I replaced them in a Sony receiver I have and they seem to work fine. Also, make sure you check emitter resistors and the various resistors on the board. On mine half of the dual-emitter resistor on the channel needing new transistors was blown and a 680ohm resistor around the transistors was blown.... there was also a 10ohm resistor around the middle of the board which looks to have been replaced (well, actually just bypassed with another 10ohm resistor) when I bought it broken off of Ebay. Good luck!
Just to help you out, I found this:
"I ordered MN2488-OPY-M and MP1620-OPY-M transistors from Sony and got 2SD2488 and 2SB1620 as substitutes."
Apparently, the MN2488 and MP1620 were just rebranded SD2488 and 2SB1620 transistors, perhaps specifically matched for Sony. They are apparently now discontinued but transistors with the same spec should work fine.
"I ordered MN2488-OPY-M and MP1620-OPY-M transistors from Sony and got 2SD2488 and 2SB1620 as substitutes."
Apparently, the MN2488 and MP1620 were just rebranded SD2488 and 2SB1620 transistors, perhaps specifically matched for Sony. They are apparently now discontinued but transistors with the same spec should work fine.
jaycee is right on. I have repaired several Sony receivers over the years using the real numbered parts. I was just about to mention this when I read jaycee's post.
I've said this before, buy your parts from reputable distributors only! The difference in cost, if there is, is never worth more than having the thing blow up again due to rebranded fake parts. Try to use original numbers (or exact factory parts), ECG's, NTE's or whatever are your last choice!!! If you must cross reference, use original data books only. Do not trust replacement brand sub books.
-Chris
I've said this before, buy your parts from reputable distributors only! The difference in cost, if there is, is never worth more than having the thing blow up again due to rebranded fake parts. Try to use original numbers (or exact factory parts), ECG's, NTE's or whatever are your last choice!!! If you must cross reference, use original data books only. Do not trust replacement brand sub books.
-Chris
Good point. I usually consider substitutions listed in cross-reference books to be valid only during design of a new circuit (where you can account for different gain, SOA, thermal requirements, etc.), not for straight replacement in an existing design. And even then you absolutely must check the manufacturer's datasheets carefully to make sure that the device suits your needs.
Unfortunately, the MN2488 and MP1620 are discontinued and not easy to find. They are not typical power transistors, they are darlingtons, and they have a fairly unique combination of voltage, current and power ratings. That makes them virtually impossible to substitute. Their popularity, especially with Sony, and their failure rate means a pretty consistent demand for replacements. That demand coupled with discontinued status means that fakes will likely be on the market.
Cheap MN2488 MP1620
This is the supplier I used in the UK
Cheap and fast service
http://www.dalbani.co.uk/index.php
This is the supplier I used in the UK
Cheap and fast service
http://www.dalbani.co.uk/index.php
Yes, they're sonically very good, especially for darlingtons. They're very fast and have reasonable SOA. Darlingtons in a Class-AB/B Emitter Follower have a relatively small Vbe-biasing sweet spot, and Sony apparently uses a carefully-controlled Sziklai Vbe multiplier with a hi-beta (>1000) master to achieve this. The rest of the stuff is usually in a monolithic analog LSI.
I'm not sure if they'll sound just as good in an all-discrete implementation without careful optimization, but at the time they were manufactured for Sony, it was probably a very optimal value-engineered design choice. The alternatives like the TIP142/147 sound much worse in similar topologies.
I'm not sure if they'll sound just as good in an all-discrete implementation without careful optimization, but at the time they were manufactured for Sony, it was probably a very optimal value-engineered design choice. The alternatives like the TIP142/147 sound much worse in similar topologies.
How to check these transistors?
Hello all, I have a Sony STR-D865. It had been working great for about 20 years and recently I heard a pop and now nothing. It popped a few fuses. I replaced the fuses, but they just popped immediately again. I have a little electronics background, but it was mostly just swapping electronics boxes while in the Air Force back when I bought this receiver 20 years ago.
I unsoldered five transistors from the unit, because I understand that these are typically what can go bad. I don't see any obvious burn marks or popped capacitors. When I check the MN2488 and MP1620 only one MP1620 shows any continuity. I'm getting continuity between the collector and emitter on that one transistor. I've tried reversing the polarity and trying every combination to see what works, but nothing.
The transistors are relatively cheap if I get them from ebay. 2 Pair MP1620 MN2488 Power Transistor 4pcs | eBay
Do you guys think they are all bad and need replacement? I have 3 MP1620s and 2 MN2488s. Is there anything else you guys would check based on your experience with similar receivers that keep popping fuses. I imagine that there is a short somewhere, but I'm not sure of the best way to troubleshoot.
Thanks!
Trey
Hello all, I have a Sony STR-D865. It had been working great for about 20 years and recently I heard a pop and now nothing. It popped a few fuses. I replaced the fuses, but they just popped immediately again. I have a little electronics background, but it was mostly just swapping electronics boxes while in the Air Force back when I bought this receiver 20 years ago.
I unsoldered five transistors from the unit, because I understand that these are typically what can go bad. I don't see any obvious burn marks or popped capacitors. When I check the MN2488 and MP1620 only one MP1620 shows any continuity. I'm getting continuity between the collector and emitter on that one transistor. I've tried reversing the polarity and trying every combination to see what works, but nothing.
The transistors are relatively cheap if I get them from ebay. 2 Pair MP1620 MN2488 Power Transistor 4pcs | eBay
Do you guys think they are all bad and need replacement? I have 3 MP1620s and 2 MN2488s. Is there anything else you guys would check based on your experience with similar receivers that keep popping fuses. I imagine that there is a short somewhere, but I'm not sure of the best way to troubleshoot.
Thanks!
Trey
Just a quick follow up. I tried mouser and they couldn't find a cross. So, I tried digikey.com. They were able to find a cross that they believe would work fine.
MP1620 -> NJW0302GOS-ND (NJW0302G ON Semiconductor | Discrete Semiconductor Products | DigiKey)
MN2488 -> NJW0281GOS-ND (NJW0281G ON Semiconductor | Discrete Semiconductor Products | DigiKey)
My receiver had white thermal grease between the transistors and the heat sink. I wasn't sure what to get for the new transistors and the tech recommended this silicone grease (860-150G MG Chemicals | Fans, Thermal Management | DigiKey).
I haven't ordered the parts yet. I wanted to hear what you guys thought, since they aren't exactly the same transistor. I have three pairs of these in my receiver. I was thinking of replacing all three pairs. What do you guys think?
MP1620 -> NJW0302GOS-ND (NJW0302G ON Semiconductor | Discrete Semiconductor Products | DigiKey)
MN2488 -> NJW0281GOS-ND (NJW0281G ON Semiconductor | Discrete Semiconductor Products | DigiKey)
My receiver had white thermal grease between the transistors and the heat sink. I wasn't sure what to get for the new transistors and the tech recommended this silicone grease (860-150G MG Chemicals | Fans, Thermal Management | DigiKey).
I haven't ordered the parts yet. I wanted to hear what you guys thought, since they aren't exactly the same transistor. I have three pairs of these in my receiver. I was thinking of replacing all three pairs. What do you guys think?
Not equivalent.
The devices you are looking for are Sanken made darlington devices, look to the current offerings from Sanken.
Audio ?Sanken Electric
The devices you are looking for are Sanken made darlington devices, look to the current offerings from Sanken.
Audio ?Sanken Electric
They sell Sanken there, but Sanken doesn't make those anymore. The tech looked at the data sheet for the MP1620 and MN2488. He said that these should be technically equivalent or better in terms of voltage handling. Are you saying that these wouldn't work? The tech spent a bit of time looking for an equivalent transistor that should work.
Sony Stereo STR-DA1500ES 2-Channel Audio Receiver
I have a Sony Stereo STR-DA1500ES 2-Channel Audio Receiver (2009/2010 model) with those transistors. This is a 2x100W+ RMS amp. Now, I get the well known "Protect" mode message and I suspect there is something blown. Speakers and headphones receives a noise signal that increases for some seconds (loud enough to kill the speakers, then protect mode shuts it down). It has the same behavior in headphones. I cannot use A/B speakers selector any more. This started to happen when accidentally I switched off the UPS instead of the amp when it was open! but I think there is more behind this.
I suspect there is the same failed transistors discussed here.
I have made some careful measurements watching some videos but as I am not an expert so I cannot be sure what I am reading, I will visit an experts lab soon. But as I am searching for the cause of fail, what I can do to be sure that those had failed? I have a very simple lcd multimeter FERM MMH-930:
The amp has 2 MP1620s and 2 MN2488s
A user here carefully suggests to replace them with the closest alternative:
The only difference in specs as far as I can see, is maximum allowed voltage, old discontinued transistors have 200V and those mentioned 150V.
I have measured 57V before the unit returns to protect mode. I guess the voltage is fixed (is it?) or it increases by volume control? Here I can only find the new couple 2SB1647 and 2SD2560. Of course I do not want to get a fake one and risk audio performance and safety. Thanks.
I have a Sony Stereo STR-DA1500ES 2-Channel Audio Receiver (2009/2010 model) with those transistors. This is a 2x100W+ RMS amp. Now, I get the well known "Protect" mode message and I suspect there is something blown. Speakers and headphones receives a noise signal that increases for some seconds (loud enough to kill the speakers, then protect mode shuts it down). It has the same behavior in headphones. I cannot use A/B speakers selector any more. This started to happen when accidentally I switched off the UPS instead of the amp when it was open! but I think there is more behind this.
I suspect there is the same failed transistors discussed here.
I have made some careful measurements watching some videos but as I am not an expert so I cannot be sure what I am reading, I will visit an experts lab soon. But as I am searching for the cause of fail, what I can do to be sure that those had failed? I have a very simple lcd multimeter FERM MMH-930:
The amp has 2 MP1620s and 2 MN2488s
A user here carefully suggests to replace them with the closest alternative:
The only difference in specs as far as I can see, is maximum allowed voltage, old discontinued transistors have 200V and those mentioned 150V.
I have measured 57V before the unit returns to protect mode. I guess the voltage is fixed (is it?) or it increases by volume control? Here I can only find the new couple 2SB1647 and 2SD2560. Of course I do not want to get a fake one and risk audio performance and safety. Thanks.
An externally hosted image should be here but it was not working when we last tested it.
If the amplifier has gone into protect it is likely the output devices have failed (at least one of them anyhow). The original devices are not in production anymore and user tale just got my last two pairs of my OEM devices. The voltage difference between the original and my suggested alternatives will make no difference in your amplifier, so if you can secure the current production devices I suggest you do so.
If you are not familiar with a repair such as this then please do refer yourself to a professional repair shop.
If you are not familiar with a repair such as this then please do refer yourself to a professional repair shop.
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