Factory upgrades of the power supply

The picture is high res. You can zoom in.
1: Red arrow. Better capacitors
2:Purple arrow. Removed fan speed potentiometer. Fan blow with full speed.
3: Yellow arrow. The front panel connectors were replaced with larger ones. Pin out similar.
4:Rose arrow. The upgraded transformer got a new connector. Pin out same. The upgrade in the transformer probably the high voltage diodes and caps. I got the old diodes out from the potted transformer. But they are not marked. So no any details. I hope higher current models. Chienese high voltage diodes.
5.Green arrow. The test button was not connected for anything on the original one. (did not work)
On the NEW one. They put an extra transistor switched by the test button. And it is just paralel to the front test button.
6. They finaly replaced the bridge rectifier with a larger higher current version.

1 Like

If you are interested what is in the high votage transformer.

It can be a voltage multiplier or just a full bridge rectifier with smoother capacitors.
I did not make a schematic out of it.
Something like bellow. That is from the net. Just to give an idea.

1 Like

The transformer was faulty. The voltage was not high enough.
I ordered the new transformer. So I had the oportunity to butcher it.
I think the high voltage diodes are probably about 25mA. That is why they die. Might just bad quality. And they brake down voltage gets lower.
But no evidence. No markings on the diodes.
I did not see the current limit resistor (R1 on the upper picture). Might I did not dig deep enough.
Might they do it by purpose. To drive they sales up.
Any way be care full to let higher current trough. Might dying tubes can kill it as well.
And I do not have high voltage power supply to test the diodes max current.
Any way you have to keep the current low as possible to extend the life of your tube. Cheap tubes has no gold wapor in it. So do not expect too much life time. And they are massively over rated as well!!!