Bass Master XM100 Type:100B

[redkurn]

Yes, you are correct. 0R27 is .27 ohms. Sorry about the typo.

It's cool, mistakes happen and I tend to make a lot of them. Which is why I am trying to make absolutely sure.

The choices I have above, which would be more suited?

[g1]

Yes, you are correct. 0R27 is .27 ohms. Sorry about the typo.

[redkurn]

Yes, they are .027 ohms. 'R' is used to designate the decimal place. Or 'K' or 'M'. 4K7 is 4700, 3M3 is 3.3Meg. 27R is 27 ohms, 0R27 is .027 ohms.
Those ones from Mouser should work fine.
When measuring (good) resistors less than 1 ohm like these, your meter will probably give you a zero reading on resistance range. Or whatever the resistance of your probes is when shorted together.

I knew of the 4k7 etc. from building pedals, but when I read that I don't see 0R27 = .027, I see 0R27 = 0.27.
I have Klein MM700 True RMS it should be able to read below .1 Ohm, here are the specs.

These are my options, I think the vishay would do fine.
https://www.mouser.com/ProductDetail...pJCCMxCAH2U%3D

https://www.mouser.com/ProductDetail...2FyyWFO9i7o%3D

https://www.mouser.com/ProductDetail...Ln6X%252BjQ%3D

https://www.mouser.com/ProductDetail...ee%252B1IT0%3D

[g1]

edit: corrected typo (.27 not .027)

Yes, they are .27 ohms. 'R' is used to designate the decimal place. Or 'K' or 'M'. 4K7 is 4700, 3M3 is 3.3Meg. 27R is 27 ohms, 0R27 is .27 ohms.
Those ones from Mouser should work fine.
When measuring (good) resistors less than 1 ohm like these, your meter will probably give you a zero reading on resistance range. Or whatever the resistance of your probes is when shorted together.

[redkurn]

You can forget about the Fet for now, your DC voltages are completely wrong. I had assumed you determined there was no DC on the output, yet you have -38V at the emitter of Q10 which is basically at the output. Unless the emitter resistor is blown. (R58 & R60)
Approx.DC voltages you should be seeing:
0VDC at speaker output.
Q10 emitter 0V
Q10 base, around 1VDC
Q10 collector 38V

Q9 emitter 0V
Q9 base, around -1VDC
Q9 collector -39V

I think you are right, the voltages are off and I can't get a resistance from those two, but I do get voltage and can get a reading of resistance and voltage from R61.

Is that 27R or .27R?? Pretty sure that's .27R... 5W00 0R27 5% BLK RES

These should be fine?
https://www.mouser.com/Passive-Compo...7+ohms&FS=True

[g1]

You can forget about the Fet for now, your DC voltages are completely wrong. I had assumed you determined there was no DC on the output, yet you have -38V at the emitter of Q10 which is basically at the output. Unless the emitter resistor is blown. (R58 & R60)
Approx.DC voltages you should be seeing:
0VDC at speaker output.
Q10 emitter 0V
Q10 base, around 1VDC
Q10 collector 38V

Q9 emitter 0V
Q9 base, around -1VDC
Q9 collector -39V

[redkurn]

The J111 pinout depends on the brand. When yorkville made that sub chart they probably had the fairchild part or equivalent, so the pinout was the same. The new ON-semi part has changed the pinout. So if you got the ON version from mouser, you need to flip it like you did.
Here's another thread elsewhere about ON changing the pinout: https://www.diystompboxes.com/smffor...=126803.0;wap2

Like I said earlier, you can just disconnect the fet for testing and the amp should work normally. It's just a mute to prevent the turn on thump.
I think it is fine the way you have it though. Your problem is that Q10 is not running.

What is the voltage at Q10 emitter?

-35.98v

I'm going to take it back a part and see if it changes with the fet out, check and see as Helmholtz suggested.
Maybe the datasheet is wrong for the part or something.

Use your Ohmmeter to find the gate: https://www.allaboutcircuits.com/tex...ansistor-jfet/

Drain and source can be exchanged without difference as Jfets are symmetrical.

I was considering doing that as well, while I had it out and think I should have checked that from the beginning as I was testing to see if it was good.

Tested it in place, the datasheet on mouser is wrong, it is the same orientation as the original part.
Guess I should let them know.

[Helmholtz]

Use your Ohmmeter to find the gate: https://www.allaboutcircuits.com/tex...ansistor-jfet/

Drain and source can generally be interchanged without difference as Jfets are symmetrical.

[redkurn]

The J111 pinout depends on the brand. When yorkville made that sub chart they probably had the fairchild part or equivalent, so the pinout was the same. The new ON-semi part has changed the pinout. So if you got the ON version from mouser, you need to flip it like you did.
Here's another thread elsewhere about ON changing the pinout: https://www.diystompboxes.com/smffor...=126803.0;wap2

Like I said earlier, you can just disconnect the fet for testing and the amp should work normally. It's just a mute to prevent the turn on thump.
I think it is fine the way you have it though. Your problem is that Q10 is not running.

What is the voltage at Q10 emitter?

I'll take a look, per ON website it matches the original pinout...
https://www.onsemi.com/pdf/datasheet/mmbfj113-d.pdf

Maybe I should desolder and flip it?

[g1]

The J111 pinout depends on the brand. When yorkville made that sub chart they probably had the fairchild part or equivalent, so the pinout was the same. The new ON-semi part has changed the pinout. So if you got the ON version from mouser, you need to flip it like you did.
Here's another thread elsewhere about ON changing the pinout: https://www.diystompboxes.com/smffor...=126803.0;wap2

Like I said earlier, you can just disconnect the fet for testing and the amp should work normally. It's just a mute to prevent the turn on thump.
I think it is fine the way you have it though. Your problem is that Q10 is not running.

What is the voltage at Q10 emitter?

[redkurn]

Can’t seem to edit my post from my phone, J111 not J11.

[redkurn]

Collector of Q10 is 38V, not the base.

Yes that is showing 38.98v, I measured the wrong leg. XD
R57 was replaced and juimped, it has -35.82v and Q4 1: -35.89v 2: -37.68v 3: -38.32v

That is bizarre that ON semiconductor would flip the pinout like that, the J111 is an established part. If that is the exact part that you got, then I would trust the datasheet.

Q10 leg at +38 volts is the collector. Emitter should be around 0V and base around +1V.

Not sure if ON did, but yorkville suggested this part as a replacement and the specs are opposite as far as I can see unless whoever made one of the datasheets made a mistake it looks like the J11 is a -35mv to active??
Also the legs are reversed, what I wonder is if yorkville intended it to be installed in the same orientation as the original, maybe that's why volume is low.

[The Dude]

Check R57. If it's good, what are the voltages on Q4?

[g1]

That is bizarre that ON semiconductor would flip the pinout like that, the J111 is an established part. If that is the exact part that you got, then I would trust the datasheet.

Q10 leg at +38 volts is the collector. Emitter should be around 0V and base around +1V.

[The Dude]

Collector of Q10 is 38V, not the base.