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D587A/B617A Output Transistor Substitute - Pioneer SA-8500II

oldtubes

oldtubes

Active Member
I puchased a Pioneer SA-8500II today at the flea market, it blow the right channel power supply fuse. I found that one pair of the four output transistors are shorted. The outputs are NEC B617A/D587A, these transistors have an odd case with mounting tabs on each side. I have tested it with just the good pair installed in the right channel. The fuse does not blow and the amp comes out of protection mode. DC offset is 1.7mV left and 2.0 mV right, so the amp seems to be healthy if I can only find some new output transistors for the right channel. Does anyone have an idea on what could be substituted for the B617A/D587A? The data sheet I found on them states they are 70W, 6 amp, 120V, hfe 40, and ft 17M.
 

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It would require drilling and tapping a hole to sub a TO-220 case, but I would go on and do it. I would sub a TIP3055 or MJE33 for the NPN and a TIP2955 or MJE34 for the PNP.
 
Update on the SA-8500II: Check several suppliers for the original output transistors and they are no longer available. I check most of the TO-220 cased transistors of current production and they all seem to have lower power rating or voltage rating than the originals. I then remembered Echowars DIY post on substituting the ouputs for the SX-1980 and started looking for an output with a different case design that I could mount on the heat sink. I ended up with the ONSEMI MJW0281A/MJW0302A. They are over kill on ratings, 250 volt, 150 watt, 15 amp, and ft 30Mhz but they could be made to fit on the heat sink. Their lead spacing is wider and they do not have a mounting tab that is the collector like the originals. I needed the bend the base and emitter lead inboard to fit into the transistor socket and run a wire from the collector lead to the socket on the back of the heat sink. I needed to remove one mounting screw for the transistor socket to make clearance for the larger case. I used a TO-247 silicon pad to insulate the transistor from the heat sink. I fired her up tonight and she came right out of protection mode in 4 sec, bias matches the left channel with the original outputs (a steady 22mA across one pair of outputs emitter resistors) without making an adjustment, DC offset is 1.2 mV on both channels. I played it through headphones and it sounds great. See the attached photo of the original and then the modified channels.
 

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On a small Class A/B amp like the 8500II, the 50W rating of the MJE15032 and MJE15033 is plenty more than enough to do the job. Output power <> the power disappated in the output devices. I simply recommended them for ease of installation (as you can easily understand now).
 
Thanks for the reply Echowars, I compared the specs of the D587A/B617A transistors to the outputs in my Sansui BA-2000 and they are the same except for a 2 amp lower current rating. Both amps are a parallel push pull design with 4 outputs per channel but the BA-2000 is 110 watts/channel and the Pioneer SA-8500II is only 60 watts/channel. It looks like Pioneer over designed this one. My mod took me about 8 hour to do including about 2 hrs of research on picking the transistors. I would not have wanted to pay a tech to do that job for a mid power amp like the SA-8500II. Thanks again for sharing your technical knowledge with us kitchen table rookies.
 
Just as point of information this thread discusses the replacement of these transistors with TO-220 case transistors (MJE15032 & MJE15033 's) using the original sockets, picking up the collector connection for each through the mounting screws, and requires NO modification of the heatsinks, although there is a little time required to fabricate the hold down bars.

Just a FYI on an alternative.

edit:

original sa-8500ii
2sb617a pnp batwing bce 120v 6a 70w 80hfe 14mhz
2sd587a npn batwing bce 120v 6a 70w 80hfe 14mhz

original sa-9500ii
2sb618a pnp batwing bce 150v 7a 80w 80hfe 14mhz
2sd588a npn batwing bce 150v 7a 80w 80hfe 14mhz

the initially recommended replacement parts, 50 watts: (a bit light )
863-MJE15033G pnp to-220 bce 250v 8a 50w 30mhz 70hfe $0.87
863-MJE15032G npn to-220 bce 250v 8a 50w 30mhz 70hfe $0.87


more powerful to-220 batwing replacements, 80 watts, just what we need!!!
512-FJP1943OTU pnp to-220 bce 230v 15a 80w 30mhz 80-160hfe $1.21
512-FJP5200OTU npn to-220 bce 230v 15a 80w 30mhz 80-160hfe $0.85
 
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The official Pioneer repalcement is to use 2SA1265, 2SC3182 as subs. You will need a new insulator. What you do is mount the new transistors in one of the mounting holes, and point its legs towards the other hole. Then attach wires to each leg and solder them to the appropriate point as if the new transistor was mounted at a right angle. Does this make sense? Pioneer supplied a kit with 2 transistors and 2 insulators. I hope this helps. I would not recommend 2n3055 as a sub.
 
Nakdoc said:
The official Pioneer repalcement is to use 2SA1265, 2SC3182 as subs. You will need a new insulator. What you do is mount the new transistors in one of the mounting holes, and point its legs towards the other hole. Then attach wires to each leg and solder them to the appropriate point as if the new transistor was mounted at a right angle. Does this make sense? Pioneer supplied a kit with 2 transistors and 2 insulators. I hope this helps. I would not recommend 2n3055 as a sub.
Click to expand...


doc: :D

I DID this, with TO-220 MJE15032 / MJE15033 's :

attachment.php


attachment.php
 
EchoWars said:
On a small Class A/B amp like the 8500II, the 50W rating of the MJE15032 and MJE15033 is plenty more than enough to do the job. Output power <> the power disappated in the output devices. I simply recommended them for ease of installation (as you can easily understand now).
Click to expand...

Thanks for leaving this here. I just ordered a half-dozen sets for my own project. I'll report.
 
Hi Folks, would like to ask if there is a more modern replacement for these currently available? Besides the MJE15032 / MJE15033 is there a beefier solution available?

more powerful to-220 batwing replacements, 80 watts, just what we need!!!
512-FJP1943OTU pnp to-220 bce 230v 15a 80w 30mhz 80-160hfe $1.21
512-FJP5200OTU npn to-220 bce 230v 15a 80w 30mhz 80-160hfe $0.85

The above are no longer available from mouser

What about the following??
upload_2020-7-13_20-5-31.png
upload_2020-7-13_20-6-19.png


Thanks
 
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I would appreciate it if someone could throw an eye on the parts above, are they a good match with originals albeit totally different case style?
I'm trying to learn but struggle with this stuff
 
PTL-Pioneer said:
I would appreciate it if someone could throw an eye on the parts above, are they a good match with originals albeit totally different case style?
I'm trying to learn but struggle with this stuff
Click to expand...



The data sheets you included are the exact same part that you say "The above are no longer available from mouser".....

they ARE available from mouser, but the 5200 is end of life and they only have one.... so not a good choice any longer.
512-FJP1943OTU as 512-FJP1943RTU
512-FJP5200OTU as 512-FJP5200RTU

A lot of fooling around was done to keep to smaller high power to-220's, where to-3p higher power cases are more plentiful.
like for example:
863-mjl4302ag
863-mjl4281ag
These are used in the SX-1980 and SX-1280. there are others
 
Well, I have just got a quartet (for one channel) (NOS) of the original transistors from a source in South Korea. I want to have at least one channel set as backup.
 
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