I need help fixing a Sony GDM-FW900 24” CRT

[lti]

Re: I need help fixing a Sony GDM-FW900 24” CRT

All eHow articles are that stupid.

Never damage your monitor. If you do damage it or accidentally drop it, seek the help of a professional to get rid of it.

Get rid of what?

For some reason, they added this to the end of that line:

Read more: Safety Precautions With CRT Monitors | eHow.com http://www.ehow.com/info_8369667_saf...#ixzz1ucrjrFLY

How did they add that to the clipboard?

Will they get a triple WTF?

[momaka]

Re: I need help fixing a Sony GDM-FW900 24” CRT

Noooo! She's still dead.

After installing the new FBT, problem is still exactly the same - spark gap SG902 gives off a nice blue flash for a second, then the HV supplies cut out and restart only to have the same cycle repeat.

I did notice something else too, though - there's is also a blue flash coming from inside electron gun. If I'm not mistaken, that would mean that the tube is indeed leaky, as KC suggested in post #8.


The last 2 attached pictures below show when SG902 is glowing (2nd to last pic) and the internal arcing of the electron gun (last pic).

I've given almost everything on the D-board a basic DMM check and nothing seems to be obviously bad. Attached in the zip file is a PNG image that shows what has been checked. Basically anything with green/blue/yellow/red has been checked.
Green means the component gave me proper measurements on the DMM.
Blue means the component gave me an okay measurement as far as I can check with a DMM (like for example a cap not showing shorted on the DMM)
Yellow means I couldn't get a proper measurement from the component most likely due to other components.
Red - something obviously wrong. There is nothing with red on the D-board other than D914 which actually is a component that does not exist on the D-board and has been replaced with a jumper wire JW5 from the factory.

When I have time, I'll pull out those components marked with yellow and test them out of the board.

I'm also thinking about testing the monitor with various HV wires (like G2 and the 2 focus wires from the FBT) unplugged from the A-board to see if the symptoms change. Would this actually be a bad idea?

The other thing I'm thinking about is swapping the D-board (and possibly A-board) from this monitor to the good one to see if that's the problem at all. Now that I've taken this monitor apart a few times, I'm a lot more comfortable with moving boards around. I actually did find a way to remove the D-board without disturbing the S-board. Didn't know that the white connector that's attached to the 2 focus wires on the FBT can actually be detached from them. Doing so allows me to pull the focus wires without moving the whole front plate for the A-board.

Apart from that, that's all for now. Decided to include a few random inside pictures of the monitor just for those that still might be interested (anyone?).

The 4th pic shows the white connector for the 2 focus wires removed. This is what you have to do if you want to remove the D-board without moving the S-board and A-board front plate.
5th pic shows the focus wires fed through and white connector installed on them.
The last 2 pictures show the arcing.

[Th3_uN1Qu3]

Re: I need help fixing a Sony GDM-FW900 24” CRT

Unfortunately, that arcing in the neck is a dead giveaway of a cracked tube. Sorry.

[pr0ton]

Re: I need help fixing a Sony GDM-FW900 24” CRT

Sorry to hear your FW900 isn't working.

For me, unfortunately, Sony stopped producing the FBT. Just when I have the infamous defocussing error caused by a faulty FBT. If you ever decide to dump the monitor, I might be interested in buying the FBT..

[momaka]

Re: I need help fixing a Sony GDM-FW900 24” CRT

Hi pr0ton,
yes, still have the monitor both with the old and new FBT. Glad to see there's more people still using these monitors.

I'm surprised that Sony stopped producing the FBT just now, though. I bought my replacement FBT in May from here:
http://www.encompassparts.com/item/4...Nx-4504j1d4%29
Looking at the link now, I think you may be right. Before, it used to say "0 in stock but available as a special order" and now it doesn't say that. www.partstore.com also used to have a page for that FBT, but that is gone as well.

I hope it really is the FBT that's bad in your monitor and not the tube loosing vacuum as kc8adu mentioned.

Not sure how much the shipping would cost from here to the Netherlands, but if you do decide to buy the FBT, send me a private message so we can discuss. I'm willing to let the FBT go for much much cheaper than what i got it for. I also have family members and friends traveling to Europe often, so there may also be the possibility that they can take the part with them and mail it to you from a post office somewhere from within Europe (if it's cheaper that way).

-----

As a small (and probably irrelevant) update to this thread, I decided to do some experiments with my dead tube.

Some of the things I tried with the HV wires were these:

I'm also thinking about testing the monitor with various HV wires (like G2 and the 2 focus wires from the FBT) unplugged from the A-board to see if the symptoms change.

- With the G2 and/or 2 focus wires removed (or the entire A-board for that matter), there was still arcing coming from the tube's back and SG902.
- With the main HV supply wire disconnected from the tube, the monitor actually stays turned ON but there's no picture (obviously).
- With the main HV supply wire disconnected from the tube and running through a dead (blown) incandescent light bulb, the HV jumps and creates a nice arc in the incandescent bulb, but SG902 still arcs and the monitor still shuts down.

Another thing I tried was feed the heater with an external power supply to see if it glows. I tried everything between 1.5V to 9V, and there was no glow at all coming from the heater at the back of the tube! On my working GDM-FW900, you can clearly see the heater when the monitor is running.

Finally, one the last things I tried was to hook my own high-voltage power supply. Basically, I used 555-based PWM circuit to make a simple single transistor forward inverter power supply with a TV flyback (had about 15 turns of wire on the TV's flyback and supplied by a 20V 3.5A laptop power adapter). Judging by the length of the arc that the flyback made when not powering anything, I'd guesstimate it was making around 5 to 10 kV maybe (or maybe up to 15 kV, I don't know for sure). Regardless, when I had this plugged in to the dead tube, I could hear arcing coming from the back of the monitor accompanied by the smell of ozone - so the tube is definitely leaking HV! But I can't see from where exactly. Also, it doesn't matter if I have the A-board disconnected from the back of the tube or not - the tube arcs regardless, just like it did with the monitor's own HV power supply.

So next step (when I have time) would be to completely take the monitor apart - and by completely, I mean everything... all boards, focus coils, deflection, yoke... just everything down to the naked tube. After that, I'm planning on connecting my HV power supply again to see if I can spot where it's arcing. When assembled, the monitor is just too crammed with components to see where the arc is coming from. If I can't spot it, then I'm guessing it would be the internal coating arcing to the external through a micro-crack or something along those lines??? I guess we will see.

One last thing I forgot to mention...
The power supply in this dead GDM-FW900 was actually originally from my working GDM-FW900. The reason I swapped them around was because the working GDM-FW900 would not always come out of stand-by (hence why the guy gave me 2 monitors). After some fiddling around with the above tests, I noticed that the PSU had some obviously cracked solder joints - more precisely, IC651 (the heater regulator) and IC652 (5V standby regulator). In fact, IC651 had lost contact on almost all 5 of its joints. After resoldering, the dead GDM-FW900 now at least tries to start all the time (whereas before, it would sometimes get stuck in standby and not arc ).

I'm not sure what a missing heater voltage would do for a normally working monitor (perhaps just loss of picture / blank screen), but if you have a GDM-FW900 that doesn't want to come out of standby, definitely check the joints in the PSU, especially around IC652.

[pr0ton]

Re: I need help fixing a Sony GDM-FW900 24” CRT

Damn, I missed your post. Still around?

When I get my hands on a FBT, I will bring it to someone who was in the CRT business. I'm pretty sure it's the problem, but shall share more details when I know you are still around .

[Th3_uN1Qu3]

Re: I need help fixing a Sony GDM-FW900 24” CRT

I'm not sure what a missing heater voltage would do for a normally working monitor (perhaps just loss of picture / blank screen)

That's exactly what it'll do.

[momaka]

Re: I need help fixing a Sony GDM-FW900 24” CRT

Damn, I missed your post. Still around?

Yup, still around. I don't think I'll be leaving badcaps.net anytime soon.

And for anyone else who may be wondering, I still have ALL of the boards from my dead FW900. So if anyone needs a certain part, feel free to contact me, even if you find this thread a few years from now.

...

By the way, with my other big monitor, the 21" Dell D1626HT also going a bit on it's way out, I started to look around in the schematics, particularly of the D board and the flyback area. Aside from the HV_det circuit, which might be just slightly different, everything else (and most importantly the HV drive circuit and HV control/feedback circuit) seem to be identical, down to component values. And the tube voltage too: 28.5 KV.

So I think there may be a possibility that the flybacks from some of the 21" Sony's are interchangeable with the flybacks of the FW900's (provided the FBT pins are wired to match, of course).

I know schematics for the Dell P1110 A board perfectly match those of the FW900, so I'm thinking all of these bigger Sony monitors are very similar inside and other parts may be possibly interchangeable too. Any thoughts on this?

[Uphill Gardener]

Re: I need help fixing a Sony GDM-FW900 24” CRT

So I think there may be a possibility that the flybacks from some of the 21" Sony's are interchangeable with the flybacks of the FW900's (provided the FBT pins are wired to match, of course).

I know schematics for the Dell P1110 A board perfectly match those of the FW900, so I'm thinking all of these bigger Sony monitors are very similar inside and other parts may be possibly interchangeable too. Any thoughts on this?

This interests me a lot. I have a battered GDM-W900 (not the FW900, sadly).
Got it free after it took a tumble down some stairs. Front buttons were smashed, inc the PCB behind them.
Found out that they saved IO lines by using a different resistor value for each button, all feeding an ADC.
From the values of the existing components on the PCB fragments(!) I was able to work out the progression and repair it.
Its like the FW900 just limited to 1920x1200@72, and no USB hub.

Problem is that I suspect the flyback is on the way out.
It started with it gradually loosing focus, then there would be a 'snap' and it would be in focus again.
After a while it stopped snapping and just stayed out of focus permantly.
I assume thats because whatever windings on the flyback that were sometimes arcing just permantly shorted together.
I solved that issue by opening the back and finding the focus pot on the flyback, then had the fun of trying to work out how to make a small hole on about three layers of the casing so I can always have a plastic crosshead screwdriver in there for adjusting the focus.
I have to tweak it about 3 times a day, but no snapping anymore.

I know Im on borrowed time, the snapping stopped about 3 years ago and Im paranoid about it dying every time I switch it on!

Id be so happy if I could work out what other types I could strip a FBT from in order to get another few years out of this delightful monitor.

Im pretty good at electronics so Im not intimidated by the work, I also have plenty of tools and test gear (inc HV voltmeter).

The other annoying thing is that theres no serial header like there is on the FW900, theres an odd miniDIN on the back thats labelled Service Port.
Im sure its just a serial port but I cant find ANY data at all.
Anyone know its pinout/baud rate etc? Or even if WinDAS etc will talk to it?

I know it wont last forever, but Im so used to its inky blacks and rich colours.
I'll eventually end up with one of those cheap 27" IPS 25x14 things from Korea. They're nice, but they're not the same.

[momaka]

Re: I need help fixing a Sony GDM-FW900 24” CRT

This interests me a lot. I have a battered GDM-W900 (not the FW900, sadly).
Got it free after it took a tumble down some stairs. Front buttons were smashed, inc the PCB behind them.
Found out that they saved IO lines by using a different resistor value for each button, all feeding an ADC.
From the values of the existing components on the PCB fragments(!) I was able to work out the progression and repair it.

Wow!
A 40 kg beast tumbling down the stairs - that's scary. I'm surprised the tube didn't get cracked. Those things must be really tough then.
Then again, the way Sony did the design on that monitor, there is virtually no force exerted from the A board on the neck of the monitor. If this was any other monitor, I bet the neck would have snapped.

Id be so happy if I could work out what other types I could strip a FBT from in order to get another few years out of this delightful monitor.

Would probably have to be another Sony monitor with similar kV rating at the very least. Like I mentioned, I suspect the design of the flyback on some Sony monitors is identical. The pins of the FBT may not match perfectly, but if you do some re-wiring of the pins, it may be possible.

I just checked the CPD-E500-E_G1 chassis service manual, and in it the A and D board schematics appear to be identical to the GDM-FW900's at a glance. I also compared most of the component values around the flyback, and they all matched too. So a good chance the flybacks may be interchangeable.

Recently, I also aquired a Sony CPD-E540 monitor, but the schematics of the A and D board look quite a bit more different. Again, I compared some component values around the flyback, and *most* seem to match, but not all. So using the flyback out of a CPD-E540 monitor may not be possible (or perhaps not without some heavy tweaking and good understanding knowledge of CRT technology). Then again, the E540 is arranged quite differently inside and everything is on one big board (like other cheaper monitors). Someone did a teardown on EEVlog, so here it is:
http://www.eevblog.com/forum/reviews...e540-21%27%29/

The other annoying thing is that theres no serial header like there is on the FW900, theres an odd miniDIN on the back thats labelled Service Port.
Im sure its just a serial port but I cant find ANY data at all.
Anyone know its pinout/baud rate etc? Or even if WinDAS etc will talk to it?

No idea either, but I have a very old HP Trinitron from 1994/1995 that uses the same port type. Considering how similar the FW900 and W900 are, I would be inclined to think it is the same thing that the FW900 has, but just with a different port connector. But again, that's only a guess.

I know it wont last forever, but Im so used to its inky blacks and rich colours.

I know what you mean . When I can, I take my CRTs with me anywhere I go.

[Uphill Gardener]

Re: I need help fixing a Sony GDM-FW900 24” CRT

Thats some really useful info there, thanks a lot!

The stairs tumble was while it was in a cardboard box with some foam peanuts inside, it originally belonged to a guy I repaired some stuff for via FreeCycle.
He had 3 that he'd bought new! They sat on a really nice custom made wooden desk.
After I admired the two he had working he offered me the broken one for parts, still in its box with ominous rattling bits inside.

I took it on the grounds that by the look of it thered be some juicy salvage inside.
Once I saw the CRT was intact I emptied the plastic shrapnel and odd metal clips & screws out of the casing, checked the looms for good connections etc and stuck some power on it.
Amazingly it came up with a no signal message, but once Id put a signal on it I saw the lower right quadrant was green tinged and fuzzy.

After I rebuilt the front PCB with the controls on I was able to adjust the landing etc and now it works fine, apart from the focus issue I mentioned.

Its scruffy as hell, but to my mind form follows function, so as long as it works the aesthetics are secondary...

In the (very poor) photos you can see the damage and the screwdriver permanently stuck in the focus pot.

The monitor beside it is a Compaq P1220 which I recently picked up for £30.
Ironically it also seems to have a focus issue, but I havent had the back off it yet for a fiddle.
Theres a chance its an adapter problem, in part anyway.
I've a GTX660 which has ONE DVI that has analogue output, so that attaches to the GDM-W900 via 5x BNC.
The only other way to get another VGA type output is via a DisplayPort to VGA dongle, and I suspect it struggles at 1920x1440.

No idea either, but I have a very old HP Trinitron from 1994/1995 that uses the same port type. Considering how similar the FW900 and W900 are, I would be inclined to think it is the same thing that the FW900 has, but just with a different port connector. But again, that's only a guess.

With that in mind I suspect what I'll do is ID the ground pin, and then just ring the changes on the other pins till it works.
I'll put maybe a 10k resistor in series with the data lines to stop anything too exciting from happening.
I need to have a root through the WinDAS stuff to see if its a TTL level serial port or a 'proper' one.
Luckily I have a real RS232 port on my PC as well as a cheapo USB -> TTL serial thing so either is OK.
If I get it working I'll either edit this post or make another, in case its useful to one of the other handful of people out there who still actually use these things.

Thanks again for the info

[momaka]

Re: I need help fixing a Sony GDM-FW900 24” CRT

I took it on the grounds that by the look of it thered be some juicy salvage inside.
Once I saw the CRT was intact I emptied the plastic shrapnel and odd metal clips & screws out of the casing, checked the looms for good connections etc and stuck some power on it.
Amazingly it came up with a no signal message, but once Id put a signal on it I saw the lower right quadrant was green tinged and fuzzy.

That is an amazing story! I almost didn't believe it until I saw the pictures you posted. Poor monitor . Yet it still works and picture looks very good.

By the way, I just noticed the W900 is very different from the FW900, both externally and internally.

Externally, the W900 has the old style horizontally-curvy tube, so this suggests the tube is much older. And this is probably why the W900 has a lower resolution limit over the FW900. Most likely this older tube wasn't made to support higher resolutions and probably won't look good if you forced it to. But I like the older horizontally-curvy Sony monitors - the tubes in those seem a lot more robust than the newer flat screen ones.

As for the internals - I just had a look over the service manual for the W900, and the schematics for the D board and G board look quite different too compared to the FW900. The first thing that struck me is that the flyback is on the G board rather than the D board. Moreover, the flyback design has some differences with that of the FW900. On most monitors, the focus adjustment knobs are on the actual flyback transformer, whereas on the W900, it appears to be on a separate module that is fed high voltage from the same winding tap on the flyback as the tube HV, but just at a lower point (the wire called MV). Although this is a less common design, I don't think it's too-uncommon in Sony monitors, because my HP A4032A also uses that design. Just have a look at the pictures I attached below. (Also note the old "Service" type port. Is this what you have?)

So with that said, I am pretty sure you won't be able to use a FW900 flyback to fix your W900 (provided you can even find one anymore... well I still have 1 more as does kc8adu). But if you are really needy, go to a junk yard or city dump if you have one, and start picking up various Sony monitors and TVs. Chances are, there are probably other Sony monitors that use that design as well. Looks like an old design, so go for the older Sony monitors.

With that in mind I suspect what I'll do is ID the ground pin, and then just ring the changes on the other pins till it works.
I'll put maybe a 10k resistor in series with the data lines to stop anything too exciting from happening.
I need to have a root through the WinDAS stuff to see if its a TTL level serial port or a 'proper' one.
Luckily I have a real RS232 port on my PC as well as a cheapo USB -> TTL serial thing so either is OK.
If I get it working I'll either edit this post or make another, in case its useful to one of the other handful of people out there who still actually use these things.

Yes definitely let us know how it goes, even if that happens a year or two from now (or more) .

And oh yeah, here's a picture of the A4032A running:
https://www.badcaps.net/forum/attach...7&d=1315008911
Colors are a lot better than they appear on the pic. In fact, they are amazing since this is only a 17" tube CRT.

[Th3_uN1Qu3]

Re: I need help fixing a Sony GDM-FW900 24” CRT

As for the internals - I just had a look over the service manual for the W900, and the schematics for the D board and G board look quite different too compared to the FW900. The first thing that struck me is that the flyback is on the G board rather than the D board. Moreover, the flyback design has some differences with that of the FW900. On most monitors, the focus adjustment knobs are on the actual flyback transformer, whereas on the W900, it appears to be on a separate module that is fed high voltage from the same winding tap on the flyback as the tube HV, but just at a lower point (the wire called MV).

That's even better - it means that is a module that can be replaced separately from the flyback. Good luck finding one though.

[Uphill Gardener]

Re: I need help fixing a Sony GDM-FW900 24” CRT

Yet it still works and picture looks very good.

Yes, picture is top notch. Needs the odd screwdriver tweak for focus but I can put up with that, for now at least.

And oh yeah, here's a picture of the A4032A running:

Looks nice, theres just something richer about the colours and blacks you get from a high-end CRT that flat panels cant quite equal.
I'll concede that some of the very high-end flat panels may be getting pretty good, but since Im a Starving Hacker© they're right out of my price range. And even if they werent Im a bloody minded bugger, I love this screen and would rather spend the price of a decent panel on a sexy new 'scope or something.

That's even better - it means that is a module that can be replaced separately from the flyback. Good luck finding one though.

Yes, although Im unsure as to where the fault is located. The FBT is most likely I suppose, but it now means that just in case Im on the lookout for 2 PCBs rather than one!

The service sheet calls them both FBTs, see attached images.
Theres also some mention of the service port, its like a PS/2 connector but 8 pin. Getting to the back of the monitor for a photo is tricky - its 41kg!

If I cant find a suitable connector I'll stick a cable with pins attached into the socket and mould a DIY plug around them by using some of that hot water melt plastic (polycaprolactone?).

The one amusing downside to this CRT is that loud music of particular types ie about the 2:36 mark in this tune:
http://www.youtube.com/watch?v=cI_rfTT3VKM
causes the shadow mask to vibrate due to resonance.
6 or 7 years of it has caused no damage so far...

[momaka]

Re: I need help fixing a Sony GDM-FW900 24” CRT

I'll concede that some of the very high-end flat panels may be getting pretty good

Heh, when I see one, I will believe it. But for now, I still think LCD technology is inferior to CRT in terns of color rendition. I'm just going to wait until OLED or whatever the next technology is that doesn't use backlights. Even if that is in 20 years, I think my CRTs will still cover me until then ... well unless they make VGA/D-Sub/analog RGB completely obsolete.

I love this screen and would rather spend the price of a decent panel on a sexy new 'scope or something.

Same here.
There is no such a thing as too many tools for me .

The service sheet calls them both FBTs, see attached images.

Yes, but in reality, only 1 is truly the FBT (the flyback on the G board). The module on the D board simply takes high voltage from the flyback and then uses that to feed the potentiometers that are used for the focus adjustments. I guess what's nice about that design is that it leaves you the possibility to feed your own high voltage to that second FBT module (not that I would recommend it, though, unless you absolutely know what you are doing). If I was to try that, it would be on a dead monitor since I don't really know what the effects can be on the tube from doing that.

The one amusing downside to this CRT is that loud music of particular types ie about the 2:36 mark in this tune:
http://www.youtube.com/watch?v=cI_rfTT3VKM
causes the shadow mask to vibrate due to resonance.
6 or 7 years of it has caused no damage so far...

Hehe, Drum & Bass will make a lot of things vibrate and shake when you blast it on high volume . I love that stuff too, especially Liquid Drum & Bass.

Your Sony uses an aperture grill, though, and not a shadow mask (as can be seen from the two fine black horizontal lines at 1/3 and 2/3 across the screen). This is what allowed the screen on early Sony monitors to be vertically flat without showing much distortion. "Modern" flat screen shadow mask CRTs may appear flat on top, but the inner surface of the screen is still slightly curved both horizontally and vertically. All in all, though, both technologies have slight advantages and disadvantages over each other. Personally, I don't mind the horizontal black lines on Sony CRTs at all (which some people do).

[Uphill Gardener]

Re: I need help fixing a Sony GDM-FW900 24” CRT

Your Sony uses an aperture grill, though, and not a shadow mask

Nomenclature fail on my part, sorry.
I noticed them when I first repaired it years ago and was setting up colour and white balance etc.
Once seen they unfortunately cant be unseen, but they're only visible against a bright white background in a dark room.

Its still alive, in fact been stable for ages. No snapping noises or need for refocusing. Im loath to disturb it to get to the service port at the back (theres at most about 9" of clearance between the back and the wall/window.

Although I obey the Type-2 geek archetype (tall & thin (Tom Jennings) rather than Type-1 fat & bearded (Richard Stallman)), I struggle to fold myself into the configuration required to get there without jolting the desk/monitor structure along the way.

I suspect whatever insulation fault caused the snapping/shorted turns in the FBT has reached its maximum extent, for now at least.

I may have to move house soon so that'll probably be the death of it. If not I'll hang a cable out the back of it round to the front for ease of access, then I can put some current limiting resistors on the serial lines and ring the changes till something works.
I'll probe them at the monitor end with a scope first to see if I get a true RS232 voltage swing or whether its likely to be TTL level.

Wow!
A 40 kg beast tumbling down the stairs - that's scary. I'm surprised the tube didn't get cracked. Those things must be really tough then.
Then again, the way Sony did the design on that monitor, there is virtually no force exerted from the A board on the neck of the monitor. If this was any other monitor, I bet the neck would have snapped.

Luckily it was quite well wrapped in bubble and cardboard. Guy who owned it had 3(!) he bought new, all aranged on a custom made desk.
When he moved house someone dropped it.
I was on FreeCycle and saw a nice 1970's receiver/amp with what sounded like a minor fault going for free. When I got there and he knew I did electronics I ended up with some paid work repairing some guitar amps for him, when I was leaving he mentioned this huge monitor that was smashed.
I thought OK, probably be some nice FETs, heatsinks etc inside so I took the whole thing (still sealed inside packaging).
Thought the CRT was smashed because there was a lot of tinkling noise from broken bits inside. Luckily turned out only to be bits of casing and PCB.
Couldnt believe my luck when I cleaned it up and switched it on!

Im still on the lookout for another one so if theres anyone within 150 miles or so of Nottingham with a 24" CRT monitor ie GDM-W900, GDM-FW900, or any of the HP, Sun, or SGI versions they want rid of please let me know!



I'll motivate you with whatever negotiable commodities you find most agreeable...

[Annabelle1]

Re: I need help fixing a Sony GDM-FW900 24” CRT

"And for anyone else who may be wondering, I still have ALL of the boards from my dead FW900. So if anyone needs a certain part, feel free to contact me, even if you find this thread a few years from now."

...

I do this now: Still yet i was working with my GDM-FW900. But now the FBT also is broken. And as you said, nobody sells that.
Do you still have yours??? Is there an alternative to Sony part 1-453-348-11 ?
Hope for an answer!!

I have an older Elsa 24H96: Is anybody there, in Europe, who wants to have spare parts?

[momaka]

Re: I need help fixing a Sony GDM-FW900 24” CRT

Hi, sorry for the delayed response.

Yes, I still have all the parts from my dead GDM-FW900 monitor (including the faulty tube itself). I gave my replacement flyback transformer to someone already, but I still have the original one from the faulty monitor. It should be working fine, though.

Anyways, before you try to buy any replacement parts, first tell us what are the symptoms of your GDM-FW900 monitor. I found over the years that these newer Sony monitors have multiple issues, so it's worthwhile investigating a bit before concluding you need a new flyback.

[SpiderWaffle]

Re: I need help fixing a Sony GDM-FW900 24” CRT

Hi All GDM-FW900 owners/troubleshooters. I was considering picking up this one locally to repair:
Ebay listing

Craiglist listing

He writes “Needs work, image not clear, has green/blue lines in display. Its very "bright" the image distorts when there's a shift if color image, the text isn't sharp, it is fuzzy.”

and

"the screen is bright, image isn't sharp and it has green lines on it."

and there's lots of images for reference

So it is "working" but has these image problems.


Is this an identifiable problem that can be reasonably fixed?

Before I bother picking this up, Thanks!

[momaka]

Re: I need help fixing a Sony GDM-FW900 24” CRT

"the screen is bright, image isn't sharp and it has green lines on it."
...
Is this an identifiable problem that can be reasonably fixed?

Looks like classic over-brightness issues with retrace lines. It affects quite a few Sony monitor models, not just the GDM-FW900. It's fixable.

With the GDM-FW900, there is a drift-correction circuit on the Cut Off Amp on the "A" board that is partially responsible for this issue. Disabling it (by putting a jumper between Collector and Emitter on transistor Q401) could partially or fully fix the monitor. See this particular post:
https://www.badcaps.net/forum/showpo...7&postcount=25
If the screen is too dark after disabling the drift-correction circuit, you may need to adjust the brightness of the monitor with a software called WinDAS and a Serial to TTL converter cable.

Here is the whole tread from the beginning, where Th3_uN1Qu3 describes how he does the adjustment with WinDAS:
https://www.badcaps.net/forum/showthread.php?t=16126

WinDAS software can be found in post #24.

As for the weak/bad focus, that could be due to the high brightness output of the monitor. I've seen some CRT monitors do this when the colors and brightness are turned too high. So in this case, fixing the over-brightness issue could also fix the focus issue.

Hope this helps. Let us know how it goes.