SSLV1.1 builds & fairy tales

[AndrewT]

You have to swap ALL the semiconductors when you change the supply polarity.

If you label the +ve side with a +ve and then trace through the current routes you will find that the diodes PASS current to the new -ve terminal.

 

[merlin el mago]

Thanks Andrew, I guess I have to reverse the capacitors polarity also?

 

[Salas]

You reverse capacitors and diodes while using a PNP for a negative polarity mirror circuit.

 

[merlin el mago]

Salas installed the cmult between the psu (caps + rect) and the BiB (BJT output MJE15029 + 4 yellow LEDs as CCS + 2 red LEDs & 1K as Vref) powering the BIII

-Vref LEDs lit without load, with load don't lit
-CCS LEDs don't lit with or without load
-Vout without load 5.1V
-Vout with load -0.6V

Without cmult the BiB is going on OK with R1 2R4 voltage accros 1.9V so current is 792mA, Vout wih BIII connected 5.1V.

With cmult connected I measured V accros R1 with BIII connected 0.017V : 2R4 = 7mA, gotcha I have to decrease R1 value to set the current but the question is: have I to add more LEDs to the 4 LEDs that I have in the CCS?

Main tx is 9V 30VA, mains filter cap is 2.200uF

 

[Salas]

What transistors you used in the Cmult?

 

[merlin el mago]

MJE15030G

 

[Salas]

Remove the protection diodes in case they are wrong. You have nothing to do to the Bib 1.1 since it works well when alone. The Cmult has to work correctly and to pass as much current the Bib wants.

 

[merlin el mago]

OK

 

[merlin el mago]

Removed the protection diodes, now I have maximum 4V at the BIII input, changed R1 2.4 ohms for 1 ohm and max 4.2V at the BIII input, always 4 yellow LEDs CCS don't lit.

 

[Salas]

Don't modify the regulator. There has to be about 1.5V drop across the multiplier and the regulator must work as usual. If there is much drop across the multiplier then there is not enough voltage for the regulator. Means have to troubleshoot the multiplier. That all is OK connected as in its schematic and its transistor is healthy.

 

[merlin el mago]

Atlas DCA55 says MJE1505G is faulty, I will change for a new one.

 

[merlin el mago]

Measured again once desoldered and now Atlas DCA55 says MJE1503G is OK

 

[nezbleu]

If I were you I would test the output of the multiplier into a resistive load. Start with a high resistance to draw little current, measure output voltage, then decrease load resistance until you are drawing more current than the regulatory needs. Measure voltages and temperatures at each step.

 

[Salas]

It can't measure correctly when in circuit. Does it say NPN? Wire in circuit what pins Atlas says for cbe..

 

[Salas]

If I were you I would test the output of the multiplier into a resistive load. Start with a high resistance to draw little current, measure output voltage, then decrease load resistance until you are drawing more current than the regulatory needs. Measure voltages and temperatures at each step.

Good method. Before an accident happens during tests to rest of components.

 

[merlin el mago]

If I were you I would test the output of the multiplier into a resistive load. Start with a high resistance to draw little current, measure output voltage, then decrease load resistance until you are drawing more current than the regulatory needs. Measure voltages and temperatures at each step.

Good method. Before an accident happens during tests to rest of components.

Many thanks guys, with resistive load 6R8 I have 534mA but the voltage drops to 3.8V

I guess I need other more powerful transformer.

 

[merlin el mago]

My guess about the transformer is OK?

 

[Salas]

No, because it holds when serving the regulator alone at 700+ mA. Its a Cmult circuit tested at 90mA load and I think its resistors don't let it perform low drop in so high current you test it for. Try with 47R and 100R instead of 470R and 1K. Use 15-20 Ohm dummy.

 

[merlin el mago]

OK I will try & let you know.

 

[merlin el mago]

Salas works like a charm, now is time to listening session.