Did you already check the fuse F001 for continuity?

mkarcher wrote on 2025-09-24, 17:02:

Did you already check the fuse F001 for continuity?

Thanks for the reply. After a bit of a struggle, I managed to get access to the back of the main board and locate F001. Yes, it has good continuity. Guessing that means it's gonna be something beyond my capabilities 🤣.

Leety McLeet wrote on 2025-09-25, 10:54:

Guessing that means it's gonna be something beyond my capabilities 🤣.

That depends how badly you want it to work again and if there is anyone near you that could fix it. A completly dead CRT monitor is unusual if the fuse is not blown. Any signs of life at all? LED (if there is one) doing anything? Any ticking sound from the PCB?

There might be a inrush current limiter for example that went open circuit. See that big black cap near power socket? The 400V one? That's the main input cap. You can check if it has any voltage on it, preferaby don't do it live if you have not worked on CRTs or mains operated equipment in general. If the monitor doesn't power on the cap should stay charged for minutes at least. So plug the power cable, plug it into wall, then unplug. Then measure (carefully, not to shock yourself) the voltage on that cap. It should still be reasonably high, at least 200V (with 230V input). If not you can suspect the inrush limiter, perhaps the common mode filter choke, or the rectifier bridge to be open. Or even the wires being somehow broken inside.

In general you take it step by step to see where the power does reach and where it stops.

Zero sign of life. No ticking sounds nor does the power LED come on.

I'm going to reassemble it and reach out to some YouTubers who might be able to help. I can do basic repairs, like cap replacement, but this is well beyond me and I don't feel safe working on it. I can't disconnect the wires coming from the neck to the main board, so it's kind of hanging/leaning on the tube at the moment. Very difficult to work on. This also means I can't reconnect the ground wires 🤣, so there's NO WAY I'm gonna risk connecting it up to the mains like that.

Gutted 🙁

I have no experience with CRTs
I only want to give you some check ideas in case the problem is nothing complex

could this be a problem with the degauss circuit ?
I remember watching a video of Adrian where the degauss current limiting resistor got busted and the system would not degauss and thus would not power on

But if there is not even a ready LED maybe this is not the case

Good luck

Leety McLeet wrote on 2025-09-26, 11:14:

Zero sign of life. No ticking sounds nor does the power LED come on.

Just one more suggestion as this is something that plagues certain monitors, and could affect others if not used for a long time. Power switch. If this thing has a standard mechanical power switch that cuts off power then it might be faulty - usually it's the oxidation of the contacts. One way of testing that is soldering 2 bypass wires to switch pins to have it permanently on. If howerver it's one of those soft-on/off buttons, not a full power switch, then the culprit is most likely the PSU.

Deunan wrote on Yesterday, 07:37:

Leety McLeet wrote on 2025-09-26, 11:14:

Zero sign of life. No ticking sounds nor does the power LED come on.

Just one more suggestion as this is something that plagues certain monitors, and could affect others if not used for a long time. Power switch. If this thing has a standard mechanical power switch that cuts off power then it might be faulty - usually it's the oxidation of the contacts. One way of testing that is soldering 2 bypass wires to switch pins to have it permanently on. If howerver it's one of those soft-on/off buttons, not a full power switch, then the culprit is most likely the PSU.

I was about to post the same. Especially old 15kHz Philips monitors are notorious with failing power switches and same can certainly apply to many other tubes.

Switch should be easy to verify by measuring the continuity and resistance of the switch poles to main plugs. No need to actually plug the monitor to mains.

That's a good thought, I never thought to check that.

I'll have a look next time I get some free time and space to disassemble it again. I'm 99% sure it's got a "daughter board", if you'd could call it that, behind the buttons, so no old-school style switches.