Need Help Finding replacements Transistors for Pioneer SA-3000

[Cosmic_S]

So this amp finally burned up one of the output transistors on the left channel and since it has been repaired at least 5 times in the last 2-3 years by a 3rd party with who knows what quality replacements we decided to just buy the parts ourselves and change all 4 output transistors and all 4 drivers

Outputs
2SD848A
2SB758A

Drivers
2SD357
2SB527 (they were already replaced when my father got this amp, meaning doesnt have the originals anymore on either channel)

so as far as ive researched, for the outputs of this exact same amp one guy here on AK used pairs of MJE15030G and MJE15031G and he said it worked fine

my worry is that the originals are supposedly 80W of heat dissipation and the 15030-31 are 50W and this amp was driving some CANTON SE140 which on the back say 4-8 ohms (DMM reads 4 ohms on box terminals) so it should be outputting a little more than 40W and am worried they might overheat and die

(most of the time the amp was hooked up to a Sansui TU-519 with it its volume knob at aound 50% and the amps volume at a little over 1/4, aux input level was around 140mv max from and old phone, so its not like it was being driven hard often, only rarely)

but for the drivers ive no idea what to use, another person here was asking for the same pair of drivers but for a sansui and someone told him to use the same 15030-15031 but idk if there are better alternatives

any suggestion is greatly appreciated, the only caveat is that they have to be available and in stock on LCSC, because mouser and digikey the shipping cost alone to south america is about the cost of just getting another SA-3000 locally (over 100USD shipping)

 

[Cosmic_S]

Any ideas ? anyone ? please

from my research so far ive narrowed it down to these 3 pairs

MJE15030/31

MJE15032/33

TIP41C/42C

i know that for drivers at least any of those 3 would work fine

what am not sure is the power transistors, originals are supposedly 80 Watts dissipation and the onsemis are 50 Watts, while the ST ones are 65 Watts, now if there are better alternatives please suggest them

thanks in advance

 

[dlucy]

It is very unlikely the driver stage of your amp is pushing 40W of dissipation. The MJE150xx should work fine in that application (driver). That said, I'd use the MJG15034G and MJE15035G instead.

If the output is only 40W max, then the MJE15034G/MJE15035G should work as well.

The MJE15034/35 devices should be easy to find and inexpensive.

 

[Cosmic_S]

It is very unlikely the driver stage of your amp is pushing 40W of dissipation. The MJE150xx should work fine in that application (driver). That said, I'd use the MJG15034G and MJE15035G instead.

If the output is only 40W max, then the MJE15034G/MJE15035G should work as well.

The MJE15034/35 devices should be easy to find and inexpensive.

you are 100% correct in that the driver stage isnt pushing nowhere close to 40 Watts of heat on driver stage (they barely even get warm during normal operation).

my concern came more from the outputs that should go into the heatsink, since this amp was driving 4 ohms speakers they should get a little warmer than usual, even when driven hard the heatsinks got warm at best (not hot enough to be uncomfortable to leave your hand on them) and the outputs packaging wasnt even hot to the touch

so to replace both 2SD848A---2SB758A (outputs)
and 2SD357----2SB527 (drivers)

i should buy 4 pairs of MJE14034/35 and replace drivers and outputs ?

amp is rated for 40W at 8 ohms but since it was driving 4 ohms speakers it should be outputting a bit more

why not the 30/31 or 32/33 ? i know VCE0 is higher in the 34/35 but their collector current continuous and peak is half of the others, no idea about gain, cant read/understand that parameter yet

 

[mcdoug3721]

2SD838 Datasheet​

Type Designator: 2SD838
Material of Transistor: Si
Polarity: NPN
Maximum Collector Power Dissipation (Pc): 50 W
Maximum Collector-Base Voltage |Vcb|: 2500 V
Maximum Collector-Emitter Voltage |Vce|: 900 V
Maximum Emitter-Base Voltage |Veb|: 6 V
Maximum Collector Current |Ic max|: 3 A
Max. Operating Junction Temperature (Tj): 200 °C
Forward Current Transfer Ratio (hFE), MIN: 3
Noise Figure, dB: -
Package: TO3

 

[mcdoug3721]

Drivers 15030/31 or 15032/33

Outputs are TO3. There are a number of T204-2 options.

Compare Products​

Comparison of products

Product Info.
Image:
Check All:
Mouser Part #:	863-MJ15022G	863-MJ15023G	863-MJ15024G	863-MJ15025G
Mfr.'s Part #:	MJ15022G	MJ15023G	MJ15024G	MJ15025G
Manufacturer:	onsemi	onsemi	onsemi	onsemi
Description:	Bipolar Transistors - BJT 16A 200V 250W NPN	Bipolar Transistors - BJT 16A 200V 250W PNP	Bipolar Transistors - BJT 16A 250V 250W NPN	Bipolar Transistors - BJT 16A 250V 250W PNP
Lifecycle:	-	-	-	-
Datasheet:	MJ15022G Datasheet (PDF)	MJ15023G Datasheet (PDF)	MJ15024G Datasheet (PDF)	MJ15025G Datasheet (PDF)
RoHS:	Details	Details	Details	Details
Specifications
Brand:	onsemi	onsemi	onsemi	onsemi
Collector- Base Voltage VCBO:	350 V	350 V	400 V	400 V
Collector- Emitter Voltage VCEO Max:	200 V	200 V	250 V	250 V
Collector-Emitter Saturation Voltage:	1.4 V	1.4 V	1.4 V	1.4 V
Configuration:	Single	Single	Single	Single
Continuous Collector Current:	16 A	16 A	16 A	16 A
DC Collector/Base Gain hfe Min:	15	15	15	15
Emitter- Base Voltage VEBO:	5 V	5 V	5 V	5 V
Gain Bandwidth Product fT:	4 MHz	4 MHz	4 MHz	4 MHz
Height:	8.51 mm	8.51 mm	0 m	8.51 mm
Length:	39.37 mm	39.37 mm	0 m	39.37 mm
Maximum DC Collector Current:	16 A	16 A	16 A	16 A
Maximum Operating Temperature:	+ 150 C	+ 150 C	+ 150 C	+ 150 C
Minimum Operating Temperature:	- 65 C	- 65 C	- 65 C	- 65 C
Mounting Style:	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case:	TO-204-2	TO-204-2	TO-204-2	TO-204-2
Packaging:	Tray	Tray	Tray	Tray
Pd - Power Dissipation:	250 W	250 W	250 W	250 W
Product Type:	BJTs - Bipolar Transistors	BJTs - Bipolar Transistors	BJTs - Bipolar Transistors	BJTs - Bipolar Transistors
Series:	MJ15022	MJ15023	MJ15024	MJ15025
Standard Pack Qty:	100	100	100	100
Subcategory:	Transistors	Transistors	Transistors	Transistors
Technology:	Si	Si	Si	Si
Transistor Polarity:	NPN	PNP	NPN	PNP
Width:	26.67 mm	26.67 mm	0.335 in	26.67 mm

 

[Cosmic_S]

Drivers 15030/31 or 15032/33

Outputs are TO3. There are a number of T204-2 options.

​

am sorry, there seems there is a misunderstanding, the originals for this amp are what ive seen people calll "bat wings" so this amp has no way of mouning any "coin" type transistors

for visual reference outputs are two pairs of these

 

[mcdoug3721]

Oh the originals were batwing.

 

[Cosmic_S]

yea they are batwings, but from my research here the MT-200 is slightly bigger than batwings and the holes spacing is different too, also he was developing a batwings to to-220 adapter but it seems he hasnt finalized it or never put them on sale (never mind the price and if the shipping to south america isnt so expensive that its better to just buy a whole other amp)

 

[sregor]

IF it will fit, people have used a TO-3P type case output where they have bent the outer two leads towards the center lead, to get TO-220 spacing. They also used the old transistor as a hold down clamp. Sorry, no picture.

 

[elnaldo]

To replace the batwing transistors, I'd suggest the TO-220 mje15032/15033 (or 15030/15031, 150V or 15028/15029, 120V parts), they will be easier to fit. Those are 8A transistors, enough for a small amp. I don't think the 50W rating will be a problem if you are not playing at party levels all night long. If your amplifier doesn't run extremely hot with your usual listening levels, you'll be fine. I've done that replacement in the past, never had a problem in home evironments, at reasonable listening levels. (Again, not extremely loud, not with the volume knob at max shaking windows for hours)

 

[Cosmic_S]

yeah, due to them being clamped to the heatsink, not just screwed in like most other amps only something about the size of a TO-220 will fit in there, because otherwise the clamp would have to be gone along with the insulating washers


so i should order 4 MJE15032G and 4 MJE15033G to replace drivers and outputs and the amp should sing back to life provided it doesnt have anything else wrong with it (hopefully not)