Main > Monitor/Video Forum

Some New Updates on the monochrome 9 monitor !!!

<< < (5/5)

Rub87:
not shorting it directly but I kept like 2-3mm airgap and just powered it on briefly.

So after spending some hours more on it I still didnt really get to the bottom of what is shorting the thing out.

If I remove the BU806 HOT the short goes away and the B+ is 10v. still no light in the tube then. I test the BU806 with a multimeter and on first sight all checks out good. With the BU806 on the board and the the horizontal yoke disconnected the thing is still shortet. I was thinking if there is a short in the HV transformer between pin 1 (B+ supply) and pin 5 (goes to the HOT collector) this could be the cause? without removing the transformer I measure like 0.5 Ohm between pin 1 and 5 (BU806 off the board). as there is nothing else connected to pin 5 apart from a 220k resistor to pin2 of the TDA2595 it must mean the thing is shorted or can this winding really be so low impedance?

Rub87:
Ok so I managed to source a new flyback with the same partnumber but a different look. I put it on and the short went away and the B+ is no longer stuck to 4.x something volts.

So far so good but still the tube remains dark.

Does anyone know what would be the factory setting in terms of V+ voltage? 10v, 12v? I measured the high voltage at the suction cap and it greatly varies with the B+ with a 100 MOhm impedance. At 10V B+ its about 2500V but if I raise the B+ to 12V its only like 1.2 kV anymore.

There is a slight glow at the back of the tube. Does anyone have an idea what I could do or test next.

Navigation

[0] Message Index

[*] Previous page