First post, by UltimateElectronic

User metadata
Rank Newbie

G'day all, I have a question regarding CRT monitors and horizontal scan frequencies.

A friend owns a Topcon branded 15" CRT monitor from 1997 (Max H-Freq ~69KHz, max resolution 1280x1024 @60Hz), and he accidentally ended up feeding it a signal that somehow had a H-frequency of ~90KHz (resolution and refresh rate unknown).

Since then, as one could probably guess, the monitor is no longer so happy. Obviously, my friend hasn't really turned it on since, just in case it causes any further damage, but I imagine the damage has been done, although better to be safe than sorry. On the one or two occasions he has switched it on after this had happened (only in ~5 second bursts), it keeps flip-flopping between power on and energy-saving mode at maybe 0.25 of a second intervals (it has a relay that constantly ticks) and makes a burning smell (he said it sort of smells comparable to maybe a burnt-out resistor).

Of course him and myself can troubleshoot simple components such as resistors and capacitors, which could possibly be what went when the monitor tried to display that, given the smell the monitor is emitting (hope that's the case for his sake). I'm posting this question on here in case anyone else would have a better idea than we would as to what sort of components would be likely to be destroyed in such a situation (I imagine it may vary from model to model, but unfortunately I wasn't able to find any schematics or a service manual for this particular monitor).

Thanks in advance!