VOGONS


Need help with dead CRT

Topic actions

First post, by King_Corduroy

User metadata
Rank Oldbie
Rank
Oldbie

Hey guys maybe one of you can help me out, my Dell E770s 16" CRT just kicked the bucket this afternoon and is now not powering on at all and only faintly ticks. Honestly I've only opened up a few monitors and adjusted the focus / brightness / colour manually and that's the extent of my experience with CRT repair. I suspect this is outside of my realm of fixing but I'd like to have an idea what went wrong just the same. 😒

Check me out at Transcendental Airwaves on Youtube! Fast-food sucks!

Reply 1 of 7, by Zup

User metadata
Rank Oldbie
Rank
Oldbie

What is a "tick"?

If that's a noise, the PSU is dead (or shorted). If that's something related to image, I don't know.

I have traveled across the universe and through the years to find Her.
Sometimes going all the way is just a start...

I'm selling some stuff!

Reply 2 of 7, by keropi

User metadata
Rank l33t++
Rank
l33t++

99% this sounds like a dead flyback transformer (or LOPT) , I've had the same issue with an arcade monitor and a 1084s ... these things just kick the bucket nowdays after all these years of work. The solution is to replace the LOPT and also check/replace the Horizontal Output Transistor (aka HOT) as well since they usually die together. The HOT is a big transistor fixed to a big heatsink near the LOPT. Change both for good measure .
Remember to discharge the tube before you go messing around with it, it holds lethal current .

🎵 🎧 MK1869, PCMIDI MPU , OrpheusII , Action Rewind , Megacard and 🎶GoldLib soundcard website

Reply 3 of 7, by kixs

User metadata
Rank l33t
Rank
l33t

I don't think it's viable to repair VGA monitors as they aren't rare or expensive - at least around here. Unless you have some attachment to it 😉

Visit my AmiBay items for sale (updated: 2025-10-29). I also take requests 😉
https://www.amibay.com/members/kixs.977/#sales-threads

Reply 4 of 7, by h-a-l-9000

User metadata
Rank DOSBox Author
Rank
DOSBox Author

The better the detail photos the more help...
Hope you have at least a multimeter.

1+1=10

Reply 5 of 7, by King_Corduroy

User metadata
Rank Oldbie
Rank
Oldbie

I mean a noise and what exactly would I take pictures of since as I said I don't really know much about monitors. I've fixed LCD screens but these old CRT screens are all built onto one board so I can't just plug in a new power board. 😒

I may try to have someone repair it, also no I don't have any sentimental attachment it's just that it was probably the best / nicest looking monitor I've owned to date. Fit my aesthetic needs and had a clear colourful picture.

Also as of late it's gotten a lot harder to find CRT monitors. 😒

Last edited by King_Corduroy on 2016-04-21, 06:27. Edited 1 time in total.

Check me out at Transcendental Airwaves on Youtube! Fast-food sucks!

Reply 6 of 7, by shamino

User metadata
Rank l33t
Rank
l33t

I'm not very knowledgeable about CRTs but keropi's suspicion of the flyback is consistent with an experience with my family's old TV from the late 90s. It had a similar failure symptom a couple of times (screen doesn't power up, hear something like a relay click 4 times and give up). The first time we had a shop repair it and it was the flyback transformer. The 2nd time it failed the TV got thrown out.
If you feel comfortable with it, then I'd probably try replacing those parts keropi described.

Reply 7 of 7, by 133MHz

User metadata
Rank Oldbie
Rank
Oldbie

Flyback transformer failures aren't that common in my experience. There are specific displays where this is a common failure point due to manufacturing defects or a rough service life (e.g. arcades), but immediately blaming the flyback on any random non-working CRT you come across is way too pessimistic IMO.

A ticking sound is caused by the PSU shutting down due to overload on its output and starting back up again in an endless loop. A prime suspect is a shorted horizontal output transistor (HOT) which does not necessarily imply a bad flyback transformer - it could've blown from other issues.

You said you have experience fixing LCD monitors so you're on the right track. I'd say blow all the dust out first and have a look for cold solder joints and bloated electrolytic capacitors, sometimes you luck out and the failure is really evident. Next measure the HOT for shorts - it's normal for it to measure really low between B & E when in-circuit due to the low impedance of the horizontal drive transformer, and also some of them come with integrated low-value B-E resistors, C & E is the really important bit. When in doubt, measure it out of circuit, you shouldn't find anything more than a backwards diode junction across C-E in a good HOT. If the HOT is indeed shorted, look for bad electrolytic capacitors nearby - some techs just replace every cap on the horizontal output stage when replacing a shorted HOT, a valid shotgun approach. After that, replace it and hope for the best. 😀

http://133FSB.wordpress.com