Dlator power supply problem.

[galtjunk]

I built a dumbleator using MP Mannings power supply with the Allen TP2X transformer.

I measured the resistors and they are correct.
The heaters measure a little high at 6.8v ac.
I get about 275 volts ac.
I get 374 volts DC.
A 3.9K resistor drops b+1 to 369 volts.
A 100K resistor drops b+2 to 362 volts. The schematic shows a drop to 252 volts.
Why am I only getting a 7 volt drop off of the 100k resistor?

Here is a picture of the PS board along with a drawing.


The schematic is in the pdf file.

[rogb]

I can't see the photo too clearly, but are your top 2 diodes correctly oriented?

[galtjunk]

The top diode in the drawing is wrong. I'll fix that.
The diode in the picture has the line on the right. It provides dc from the filaments to power the led.

The second diode faces left.
The bottom diode faces right.
The crossing diodes in the center both face down.

The drawing now shows the current diode orientation

[ecisthebest]

just to be clear, do you have tubes in there?

[martin manning]

Looks like you are drawing almost no current from B+2. Measure the voltages on the tube pins. My guess is there is some wiring error.

[Structo]

I can't tell but do you have the standby switch after the diodes?

Then your B+ is coming off both sides of the 100K?

You should have the standby on the AC side of the rectifier (better for the switch).
B+1 should go to the 100K plate on pin 6 and the other node to pin 1.

[martin manning]

Check to be sure that the cathode and bias resistors for the buffer stage are the correct values... 1k8 and not 18k for example.

[galtjunk]

I had pins 2 and 3 swapped.

Everything is falling into place now.


Thanks