need a equivalent replacement for obsolete MJE15033 PNP transistor. MACkIE sub

need a equivalent replacement for obsolete MJE15033 PNP transistor. MACkIE sub
Posted by mookie1590 on 19 Nov, 2022 18:13
I'm currently repairing a Mackie subwoofer SRS1501 amp board. It came from a MACKIE SWA1501 active sub woofer. If anyone has experience repairing these, would like to know if Q18 shorting is a common issue

ON Q18 MJE15033 pnp transistor is completely shorted out. These are obsolete. The schematic is very easy to find on old tech. I'll try to upload a schematic on the amplifier board.

I can order them, but theyre 2-3 weeks out at a minimum. So wondering what the modern replacement is for these obsolete transistors.
And a second question. If I do get a replacement for this transistor, would there be an argument to replace Q5 MJE15032 on the low side of this circuit? I have ordered some before and it took 2 weeks to get them. And surprise surprise, they are f**king fakes

My main issue right now, is what can I replace these obsolete trannys with?

Also resistors R26 R73 on the secondary power circuit were fried. And on the amp board, resistor R17 is also fried. I dont understand why this one died when the othe parts surrounding it are fine. If someone could explain that for me

Also 2 more resistors on the input board, schematic SRS1800. R101 and R50 are cooked looking but meassure the correct resistances. Obviously I will replace these 2 as well. those 2 resistors are with the circuit labeled POWER ON on the bottom left of the schematic.

Total of 5 resistors and one pnp transistors is so far the damage Ive found. And they guy that asked me to repair these, has another one that wont work, I dont have it yet, but might be the same issue.

MACKIE-MAIN AMPLIFIER BOARD SCHEMATIC.pdf

#1 Reply
Posted by wraper on 19 Nov, 2022 18:36
It's not obsolete. Plenty from many distributors https://octopart.com/search?q=MJE15033G&currency=USD&specs=0. G suffix stands for lead-free package.

#2 Reply
Posted by Audiorepair on 19 Nov, 2022 19:13
The original speakers in these were 12 ohms, which you just can't get.

These are quite old now, so it might be worth checking that someone hasn't replaced them with 8 or 4 ohm drivers, otherwise it may just blow up again.

#3 Reply
Posted by Smokey on 19 Nov, 2022 19:19
Funny. I was just about to post this, when you beat me to it. Digikey to the rescue.

https://www.digikey.com/en/products/detail/onsemi/MJE15033G/919494
2,673 In Stock
QTY UNIT PRICE EXT PRICE
1 $1.91000 $1.91

#4 Reply
Posted by mookie1590 on 19 Nov, 2022 22:31
Huh, didnt even check digikey.
When I first searched that part. Ended up on mouser. and it said lifecycle, obsolete. and were not available. https://www.mouser.com/ProductDetail/onsemi/MJE15033?qs=HVbQlW5zcXXDraOLW%2FeopA%3D%3D
Then when I searched amazon, they were 2-3 weeks out, which further led me to believe they were obsolete. since normally i can get anything within 2 days off amazon.
Maybe when mouser said obsolete, it meant the one without the G suffix that you posted?

I'll just order them off digikey, should have checked there to begin with.

#5 Reply
Posted by mookie1590 on 19 Nov, 2022 22:32
good point, I'll do a quick check. someone has been in this sub woofer before, no telling what they changed

#6 Reply
Posted by mookie1590 on 19 Nov, 2022 23:12
welp, really bad news.
dunno if its the ogs in it, but there is a 16 ohm precision transducer in this. a M1575w-1501

The extra bad news, is its dead. I'm getting no resistance measurement. and just to be safe. I attached to to my scope to see if it would produce a wave. and there is no signal on my scope when I move the speaker cone.
That explains why the amp board died.

Dont think its worth fixing now. I dont think i can get my hands on a speaker for an affordable price.

You saved me a headache by telling me to check this.

unless you know of a way to repair it or get a replacement. but getting in there and trying to fox the magnet wire does not sounds like a fun time.

#7 Reply
Posted by wraper on 20 Nov, 2022 08:20
There are guys who repair speakers. I won't be cheap though.

#8 Reply
Posted by Audiorepair on 20 Nov, 2022 16:19
The cone and suspension are usually very strongly glued to the speaker chassis, so there is little hope of removing it without destroying it.

You might be able to get the dust cap off and back on again, that will gain you visual access to the coil to see how burnt it is, or not.
But there isn't really a good chance of repairing it, a recone involves ripping everything off, cleaning all the glue off the surfaces, and installing a new cone, coil, suspension and dust cap.

I have in the past done, and seen done, a temporary repair where the braids have been damaged by over excursion, they will sometimes fail open circuit either at the speaker terminals or at the point they go through the cone to the coil.
But it's an unreliable bodge at best, given the abuse the repair has to cope with.

A 9v battery is useful for testing speakers, connect it and wiggle the braids about to see if you can get it to go Pop Bang Crackle.