Re: Fujitsu monitor: power is there, but no image from PC
Finally got some time to go back to the Fujitsu-Siemens monitor, and the problem is solved, it came back to life!
The problem resided in one of the (4) NPN power transistors that drive the line transformers who drive the CCFLs. I substituted all 4 transistors, and the monitor is now working perfectly.
For [U]future memory[/U] in this Forum, here goes some highlights of the whole journey:
[B]Problem: [/B]
When the monitor is switched-on, it shows briefly the Fujitsu-Siemens logo for about one...
jvelez
Member
Last Activity: 01-11-2025, 12:14 PM
Joined: 11-01-2023
Location: Massama
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Re: Fujitsu monitor: power is there, but no image from PC
Thank you CapLeaker! Just to be sure I understood it right: in the old days, I used to test the tuning of the my homemade short wave transmitters by touching with one pin of a domestic FL in the final stage/coil (the anode tension of the tubes was enough to trigger the initial discharge of the gas, and the lamp would become more or less bright as I tuned the final RLC stage). Here, you mean actually connecting one of the CCFL outputs to the pins of one side of the lamp, right? Thank you and sorry for likely...Leave a comment:
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Re: Fujitsu monitor: power is there, but no image from PC
Thank you Iotas and Harp!
- After the question posed by Jotas I did exactly that test, and I'm pretty sure there is absolutely no hissing or visible sparkling I could notice.
- I also checked the tensions in the pins of the connector that goes from the main board to the inverter (photo), and I although I don't have the schematic I got reasonable values:
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red wire = 12volt
blue " =12volt
white " = 0 without VGA signal, 3.2 with VGA signal
yellow...Leave a comment:
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Re: Fujitsu monitor: power is there, but no image from PC
Hi Iota, No it doesn't! I just checked in total darkness to be sure, and in fact the CCFLs switch on briefly during the display of the logo, and then switch off.
I can have access to an EEPROM/flash programmer is necessary (I've built one myself, but it only works for the old UV EPROMs...).Leave a comment:
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Re: Fujitsu monitor: power is there, but no image from PC
Thank you and sorry, I forgot to mention that the behavior is still the same, the logo pops up and nothing else, no picture or reaction to pushing the menu buttons...Leave a comment:
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Re: Fujitsu monitor: power is there, but no image from PC
Thank you again for the advices!
- I checked both transformers in the inverter, and I have a max of 0.2 ohm in the longest primary coil (0.1 or even zero in the intermediate derivations), and resp. 194 and 199 ohm in both secondaries --> seems ok with the 3% ballpark rule.
- I re-soldered all transformer terminations --> indeed they seemed bad in one of the transformers.
- I checked Vdd/Vss in all ICs in the main board, getting 4.8 or 3.2 volt in all of them...
One thing I noticed: inductor...Last edited by jvelez; 11-08-2023, 05:42 PM.Leave a comment:
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Re: Fujitsu monitor: power is there, but no image from PC
Some pictures of the inverter (both sides) plus the back of the main (square) board...
Visually, I cannot spot any particular signs of damaged capacitors or similar....Last edited by jvelez; 11-07-2023, 06:46 PM.Leave a comment:
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Re: Fujitsu monitor: power is there, but no image from PC
Hi, Thank you for the hints!
- I took out and reinstalled the PROM(?) brown socket -> no changes.
- I also checked with the DMM all the FBxxx SMD components, I guess they are fuses ... all seem ok.
Same behavior:
->I see the logo in the screen for one second or so (as it has always done).
--> after that, nothing: neither image from the PC nor menu/OSM when I push the respective buttons...
I will now try to check for the Vcc in all ICs...Leave a comment:
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Fujitsu monitor: power is there, but no image from PC
Hi, seeking for guidance on the following:
I have a Fujitsu Siemens monitor T19-1 (base model is C19-1) that stopped showing any picture, besides the FS logo when it boots.
I'm attaching a picture of the system board with some additional info.
- The monitor recognizes the presence of the VGA signal: the power button switches from amber to blue, and vice-versa when the computer goes sleeping.
- The inverter + CCFL seems to be working fine: the Fujitsu-Siemens logo appears when the monitor is switched on.
- I measured the values in the power regulators:... -
Re: New Members - please post your introductions here
Hi, I decided to join this Forum after finding invaluable contributions and guidance on some topics, particularly on monitor/display repair, where my ignorance is still considerable. I'm located in Portugal.Leave a comment:
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Re: HP no backlight
I'm really happy that I found this forum: I have an HP VS19e that stopped working, and the power supply board is exactly the same as posted in this thread.
After inspecting the circuit, I found a few electrolytic caps clearly blown up, and after replacing the complete set I got power again, but the CCFLs are still dead.
I turned my attention to the inverter part of the module, and found that the chip that generates the pulses to the lamp system is not showing the right voltages.
More specifically, I101 (OZ9930) shows 0.6 volt in the PSEN instead...Leave a comment:
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