Samsung Syncmaster 757DFX flyback \ VOGONS

Samsung Syncmaster 757DFX flyback

Topic actions

First post, by x86_guy

Posted on 2025-04-10, 17:10

x86_guy Offline

Rank Newbie

Rank: Newbie
Posts: 40
Joined: 2024-03-30, 20:46

Hi there,
This monitor came to me with a cut VGA cable.
It worked and showed the standard "No signal" message. So I went ahead and re-made the cable, connecting only the basic signals using the attached pinout, just for test.

After that, turning the monitor on without being connected to any VGA signal, gave me a strong high pitch sound that reminds me a previous encounter with another monitor that had a bad flyback.

So I turned the monitor off and removed the cable I built thinking that it might be something with it. The noise still persist.

HOT seems too be fine, it's not shorted.
What is your opinion on this one? Is it possible the the flyback went bad? If so, is it something to do with the pinout diagram I attached or is it just coincidence?

On the flyback there is a stamp mentions "FQM-21A001". This P/N didn't gave too much results on google and I couldn't find a resource to buy it from.
Is it possible to find a replacement for this flyback?

Thanks!

Reply 1 of 4, by x86_guy

Posted on 2025-04-13, 19:14

x86_guy Offline

Rank Newbie

Rank: Newbie
Posts: 40
Joined: 2024-03-30, 20:46

I want to start with flyback replacement, but I can't find a replacement? Anyone have any idea about it?

Reply 2 of 4, by Tiido

Posted on 2025-04-13, 19:17

Tiido Offline

Rank l33t

Rank: l33t
Posts: 3543
Joined: 2018-01-14, 04:40
Location: Norway (used to be Estonia)

Flybacks for monitors are generally a rare breed and it is unlikely you find a replacement.

What is written on the flyback other than the FQM-21A001 ? There should be a string of numbers (8...10 digits and maybe a letter or two) on it on a label, and with luck you find a match or a compatible one, although if anything is in stock is another question...

But the problem may be a cold solder or such somewhere too. Are you able to pinpoint where the sound comes from ? Are there any problems in the image itself ?

T-04YBSC, a new YMF71x based sound card & Official VOGONS thread about it
Newly made 4MB 60ns 30pin SIMMs ~
mida sa loed ? nagunii aru ei saa 😜

Reply 3 of 4, by TheMobRules

Posted on 2025-04-13, 20:19

TheMobRules Offline

Rank Oldbie

Rank: Oldbie
Posts: 1600
Joined: 2016-01-19, 23:29

HR Diemen used to make flyback replacements at some point, not sure if they still do. Looks like the replacement for yours would be HR 47108:

https://www.hrdiemen.com/search/index?utf8=%E … ig=FQM+21+A+001

Unfortunately their site is really broken so it's not possible to see the technical specs, but maybe you can find NOS replacements out there... Donberg Electronics from Ireland still sells some old HR Diemen flybacks, maybe you can try asking them. I found a pretty rare replacement for one of my monitors there, which wasn't listed in their store but they somehow managed to source one.

EDIT: still, I agree with Tiido that you better discard other issues first, usually most components in a CRT are easy to remove and test.

Reply 4 of 4, by x86_guy

Posted on 2025-04-13, 20:51

x86_guy Offline

Rank Newbie

Rank: Newbie
Posts: 40
Joined: 2024-03-30, 20:46

Tiido wrote on 2025-04-13, 19:17:
What is written on the flyback other than the FQM-21A001 ? There should be a string of numbers (8...10 digits and maybe a letter or two) on it on a label, and with luck you find a match or a compatible one, although if anything is in stock is another question...

I don't remember anything like that but I'll check again and will update if I find a string like you mentioned.

Tiido wrote on 2025-04-13, 19:17:
But the problem may be a cold solder or such somewhere too. Are you able to pinpoint where the sound comes from ? Are there any problems in the image itself ?

Has soon has I heard this sound, I quickly turned the monitor off to make make things worse. I'm not sure whether it's displaying any image or not.
I'll check for colder solders.

Tiido wrote on 2025-04-13, 19:17:
Flybacks for monitors are generally a rare breed and it is unlikely you find a replacement.

What is written on the flyback other than the FQM-21A001 ? There should be a string of numbers (8...10 digits and maybe a letter or two) on it on a label, and with luck you find a match or a compatible one, although if anything is in stock is another question...

But the problem may be a cold solder or such somewhere too. Are you able to pinpoint where the sound comes from ? Are there any problems in the image itself ?

It looks like those flybacks aren't really reachable indeed. Anyway, first I'll check for cold solders like "Tiido" recommended. I just wanted to have an available source for the flyback, so in case I need one, it will be ready for me to order.

Thanks a lot for the help.

Go to top of page Go to top of page

Back to General Old Hardware