GT65 monitor behaving oddly

[moijk]

Faulty gt65 - YouTube

that is with my schneider 6128. The 6128 works perfectly on my telly using rgb scart.

anyone have an idea on what could be wrong, and if it is an easy fix?

[Bryce]

Hmm, most likely a capacitor on the vertical scan circuitry has died.

Bryce.

[moijk]

i see, i can replace caps on this old tth stuff. just need to know what to do not to get a gazillion volts through me from the flyback or whatever it is. and also a pointer to the location so i don't have to poke through everything with a fine comb.

[Bryce]

Just took a very quick look at the schematics... there are several capacitors in this area that could cause this or similar effects.

I'd check C711 first. But be extremely careful, this is one of those caps that can and will give you a 1000V whack that you wont forget. I'd also check C710, which only carries about 18V but everything in this area can be detrimental to your health, so discharge the circuitry before you start anything.

Bryce.

[moijk]

never have had the need to discharge a cap before. so any guide on how to discharge this would be nice, would leaving it for a week help?

I've just soldered on and off stuff, not that knowledgeable in this. but the reason why i would even bother would be to learn.

[MaV]

never have had the need to discharge a cap before. so any guide on how to discharge this would be nice, would leaving it for a week help?

In that case, seek professional help that is willing to show it to you. You really need to be shown the procedures in person, as the charges may threaten you life.
An online guide may encourage others to do so without the necessary precautions.

[moijk]

In that case, seek professional help that is willing to show it to you. You really need to be shown the procedures in person, as the charges may threaten you life.
An online guide may encourage others to do so without the necessary precautions.

well, given i then have to go to a store or repair facility as those i know with the skills live where i used to live - i think the road for this monitor is at an end. i've replaced caps in motherboards without any concerns for contained voltage. the monitor is pretty much worthless in the market and the time of professionals isn't cheap.

[MaV]

i think the road for this monitor is at an end.

Not necessarily. If they are willing to teach you the procedures, it would pay off in the long run, as you will encouter similar problems in the future.

i've replaced caps in motherboards without any concerns for contained voltage.

Are we talking 8-bit and PC motherboards? If so, neither would I be much concerned about replacing those.

As Bryce mentioned, there's a charge of up to 1000v facing you in the GT65. It may all work out well, but I would not bet on it.

I. am. serious.

[Bryce]

Firstly, if you are unsure, don't do it. But this is how I would recommend to do it:

What you need: A 220V Lightbulb in an insulated socket with insulated wires attached with 1 or 2mm of the copper visible at the end (or probes on the end of the wires if possible).

- Leave the monitor unplugged but with the power switch turned on for at least 24 hours.
- Remove the back of the monitor case.
- With the monitor lying on its side, slide the PCB out without touching anything metal on the PCB!
- Locate the large capacitors and hold the wires of the bulb across the plus and minus of each capacitor to discharge them (you will only have access to these points underneath the PCB).
- When all have been discharged, the PCB is safe to work on.

The bulb might light for a split second on some of the really big capacitors, but it might not. Don't expect a Christmas tree every time you touch the wires. Before you remove any capacitor short the plus and minus with the end of a screwdriver to be 100% sure.

Disclaimer: I am not responsible for any damage you may cause to yourself, your monitor or anything else. Do all this at your own risk.

Bryce.

P.s. It might sound obvious, but make sure the bulb works before start.

[Gryzor]

Nice tip! (bonus Like for the "working bulb reminder ).


It was funny - I opened the video and only switched tabs in time to see the cursor going below the screen - groovy!