Salas SSLV1.3 UltraBiB shunt regulator

[merlin el mago]

I have a trusty BC550C supplied by tea-bag

 

[merlin el mago]

Wich one?

 

[Salas]

Sorry a 560 not a 550. Or your 327 pnp (for Q1 in the positive reg).

 

[Salas]

1,4mV

Does not run good current that is why low Vbe. You want 0.25V-0.55V on R4. Either Q1 or J1 must be problematic.

 

[Salas]

Can I trust in this bc327?

Yes, 327-25 works for Q1 in the positive. Main thing is its Vbe and low noise not its beta in that position.

 

[merlin el mago]

Ok thanks I will try & let you know how it goes.

 

[merlin el mago]

Worse 1,1mV

 

[merlin el mago]

Must be J1, but I don't have PF5102.

 

[Salas]

Can substitute with J113 see explanation link in post one

 

[Salas]

Is R4 correct 270Ω but not 2k7 by mistake?

 

[merlin el mago]

Ok I will look

 

[merlin el mago]

Have the same pinout?

 

[Salas]

PF5102 same pinout with J113

 

[merlin el mago]

Thanks, tomorrow I will look for if I have J113 & measure Idss for R4 value

 

[merlin el mago]

Is R4 correct 270Ω but not 2k7 by mistake?

It's 270R

 

[merlin el mago]

I don't have any J113

 

[Salas]

Pull out your now J1 PF type and see if it gives Idss or not, if its really the problem. Lets establish that before we try an alternative solution like get a J113 from a store that's using R4 or try a 2SK117GR with a jumper instead of R4.

 

[merlin el mago]

Ok

 

[merlin el mago]

Pull out your now J1 PF type and see if it gives Idss or not, if its really the problem. Lets establish that before we try an alternative solution like get a J113 from a store that's using R4 or try a 2SK117GR with a jumper instead of R4.

J1 PF5102 measures 2.35mA

 

[Salas]

Very small for PF5102. Maybe an odd sample maybe a defect. Put it back and bypass R4 with a jumper to see if voltage drop across R1 goes normal 0.55-0.6V.