NPN Silicon Rangemaster/LPB-1

[Domin]

Hello,
I tried to make boost, like LPB-1, but with values of RM, everything looks ok but i dont get sound out of it.I tried to probe it but i dont get sound on base. Input caps are 10n and 470n on switch. I tried even continuity test and from wire to one side of cap its ok and from other side of cap to socket its ok, i measured caps too and values are ok...and one interesting thing, i put 5088 and 2222 and on collector and emitter i have 6,8V and on base 8,2V...i took transistor out, i measured it with diode test and it was ok, i measured socket with continuity test and between pins was no short or anything...what could be problem? I even had problem on breadboard with it...

[antonis]

Those "cuts" are very suspect..
(use a 3 or 4 mm dril bit on every pad hole..)

[Domin]

But continuity test doesnt show anything 🤔

[antonis]

Your layout puzzles me a bit..

If you plz, use different colours for cuts and jumpers..

[Domin]

Ok, do you want me to send it again?

[antonis]

Or replace initial pics..

[Domin]

Ok, its done, i changed some colors

[duck_arse]

just as a fun exercise, measure the value of the 470k resistor base to supply.

[idy]

So it didn't work on the breadboard and you decided to solder it up anyways... We breadboard to avoid this kind of problem.

Have you done any reading (search function) about this kind of thing "silicon Rangemaster?" There are reasons why the values are different. The two types of transistors have different bias requirements.

Maybe back to breadboard?

[Domin]

just as a fun exercise, measure the value of the 470k resistor base to supply.

Probably i see it, I will check it tomorrow...how i couldnt see it? I had problem to measure it, i thought that it was because of how is everything connected

[Domin]

So it didn't work on the breadboard and you decided to solder it up anyways... We breadboard to avoid this kind of problem.

Have you done any reading (search function) about this kind of thing "silicon Rangemaster?" There are reasons why the values are different. The two types of transistors have different bias requirements.

Maybe back to breadboard?

I made one with same values and its working, i tried it today so all walues are ok No need to change anything...on old pcb i put 200k trimpot to set bias and with 2N2222A it was still around 67K

[Domin]

Now its working, somehow i missread 470R as a 470K