Broken Dell 1800FP Power Supply - when and when not to resolder?

[jetadm123]

Re: Broken Dell 1800FP Power Supply - when and when not to resolder?

Usually, it's the bad joints that cause the ICE2AS01 chip to short out. A quick test for this chip is to check for a short between pins 6 and 7 (Vcc and ground). Also, remember to resolder the pads of both duo diode paks and the main transformer.

[bttmstr]

Re: Broken Dell 1800FP Power Supply - when and when not to resolder?

pardon me for being dumb right now... so when shorted it should read 0 or infinite?... i'm reading 0 between these two... so that would indicate the chip is good right? thanks...

[severach]

Re: Broken Dell 1800FP Power Supply - when and when not to resolder?

A shorted component reads 0 ohms on an ohms scale and 0 voltage drop on diode test. You can verify this by shorting the leads together. An open component reads infinite ohms.

[tmcw]

Re: Broken Dell 1800FP Power Supply - when and when not to resolder?

I've started troubleshooting one of these myself.

When the power is applied, there is no image on-screen.

The power LED seems to have erratic behaviour, sometimes it comes on and stays on, other times it won't come on. It also seems that it might come on again after I've powered down the monitor, disconnected the front panel (buttons) from where it's connected to the video board, reconnected the front panel (buttons), and reapply power.

When the LED does light, pressing the power button has no effect, the LED stays on. Pressing other buttons has no effect either.

I tested the voltages at the indicated points on the power board and got 12.13V and 4.84V respectively. This power board is thus ok, no?

[tmcw]

Re: Broken Dell 1800FP Power Supply - when and when not to resolder?

I downloaded the manual from the first few posts, and did the tests in the "No raster" section.

I get the 3 12V at pins 1, 2 and 3, but only 0.13V at pin 8; it should be 5V here. The diagnosis is "Trouble in invon pattern".

Anyone know what that means, or where to go next?

[PlainBill]

Re: Broken Dell 1800FP Power Supply - when and when not to resolder?

I downloaded the manual from the first few posts, and did the tests in the "No raster" section.

I get the 3 12V at pins 1, 2 and 3, but only 0.13V at pin 8; it should be 5V here. The diagnosis is "Trouble in invon pattern".

Anyone know what that means, or where to go next?

Yes, and Yes.

OK, seriously, 'INVON' is 'INVerter ON'. That comes from U501, pin 32.

PlainBill

[tmcw]

Re: Broken Dell 1800FP Power Supply - when and when not to resolder?

Thanks Bill.

The video/logic board in mine is different to the manual (came across the test before I saw the schematic), there is no U502.

But I did have a bit of a search and found this thread, https://www.badcaps.net/forum/showpo...0&postcount=12 so I'll go through that and the thread it's in. It's the same board as mine, so will probably get me started.

Apologies for not using the search before posting.

EDIT: And if anyone is looking for a closer manual to the 1800FP UltraSharp, this link might be of use:

[kingofcoins]

Re: Broken Dell 1800FP Power Supply - ICE2AS01 check

When we do a check on the PWM chip ICE2AS01 in this power supply, checking for a short across pin 6 VCC and pin 7 Grd,...what is a good ohm reading if zero is no good ? Is 10 ohms either way at 6-7 OK ?

[PlainBill]

Re: Broken Dell 1800FP Power Supply - ICE2AS01 check

When we do a check on the PWM chip ICE2AS01 in this power supply, checking for a short across pin 6 VCC and pin 7 Grd,...what is a good ohm reading if zero is no good ? Is 10 ohms either way at 6-7 OK ?

10 ohms is probably bad. A better approach is to measure the voltage between pins 6 and 7 (with monitor plugged in). The startup voltage is 13-14 volts. If the voltage is less than that check the diode connected to pin 6 (out of circuit). If it tests good, the IC is probably bad. The other possibility is the bleeder resistor network that provides startup power.

PlainBill

[kingofcoins]

Re: Broken Dell 1800FP Power Supply - ICE2AS01 voltage

As always Thanks Bill and Happy Holidays !!

The voltage was only about 6V twix pin 6 and 7. I also noted this board has a diode that reads 14 ohms either way, so I swapped in a board from another unit with an inverter problem and retested. This new board shows 11.6VDC at pin 6-7 on the same chip, and same at the SMPS output, and its still same 11.6VDC out of the logic to the separate inverter board. The dc output spec for this unit is supposed to be 12VDC. Is 11.6 OK, enough to do the job, or is something failing in power supply section knocking it down ?

Dan

[PlainBill]

Re: Broken Dell 1800FP Power Supply - ICE2AS01 voltage

As always Thanks Bill and Happy Holidays !!

The voltage was only about 6V twix pin 6 and 7. I also noted this board has a diode that reads 14 ohms either way, so I swapped in a board from another unit with an inverter problem and retested. This new board shows 11.6VDC at pin 6-7 on the same chip, and same at the SMPS output, and its still same 11.6VDC out of the logic to the separate inverter board. The dc output spec for this unit is supposed to be 12VDC. Is 11.6 OK, enough to do the job, or is something failing in power supply section knocking it down ?

Dan

11.6 is well within the normal range of output voltages. The usual design of dual output power supplies is to regulate one output (usually the 5V supply) and let the other output float.

PlainBill

[Surfman]

Re: Broken Dell 1800FP Power Supply - when and when not to resolder?

Hello Maverick
This Schematic will help you and Plainbill sort your problem out with luck, Its not for your monitor but its your p/suppy to a T.
Also my problems with FP1800 was,
AC input fuse, 0.33 resistor (R923), Mosfet on H/sink that resistor goes to, and power controller ICE2AS01, along with a lot of bad solder joints, particulary the diodes on H/sink that you mention, this may help you,



bob

Does anyone still have the schematic for the FP1800 power supply? The link is not working for me and my Portuguese is non-existent.



Thanks for any assistance.

[kingofcoins]

Re: Broken Dell 1800FP Power Supply - SMl ink

Manual is here, a great site is in Poland, I believe.....

[printone2]

Re: Broken Dell 1800FP Power Supply - SMl ink

Manual is here, a great site is in Poland, I believe.....

Thanks for the link. My 1800PF has a slightly different power supply problem. It would not turn on the green power light or light up the lamps, but it would make a clicking sound. I looked that up in the forum and found this link of PlainBill's:

https://www.badcaps.net/forum/showth...clicking+sound

This is the name of the thread:
"Iiyama Prolite E430S click sound"

Here PlainBill suggests:
The clicking sound is probably the smps trying to startup. The small cap proceeding it is likely bad. It is around 22uF 50V and does not have to bulge in order to be bad. It can be out of uF tolerance or have high ESR (ohms).

Well so I replaced the following caps:
C907 PDA brand 47uf 50v with a Panasonic EEU-FC1H470 also a 47uf 50v
C924 R1A brand 33uf 25v with a Panasonic EEU-FM1V330 a 33uf 35v

This gave me a working panel. It fixed the power supply output to the logic board and brought the power up to 5.2 volts and 12.2 volts, which had been about 4.x volts and 9.9 volts, respectively.

After the panel is on for about 5 minutes I begin to hear a buzzing noise from I believe the transformer at T901. I then came across this thread and saw about the poor solder joints. So I touched up the T901 and a few other solder joints like D903.

I put the panel back together and again it begins to make that noise. It is not really loud, but I am concerned that it is telling me that it might be cooking some of the caps that I just put in. Should I plan as a precaution to recap the rest of the board. It has Sam Young caps on it now.

I can post pictures, but my board looks like the ones in this thread. Just yell if you think pictures of my specific boards would help.

Also is it normal for the inverter board to glow a bit orange. The picture looks good to me, but is the orange glow I see through the holes in the metal shielding normal or is that an indication that the CCFL are old and causing other problems. This board was built in 2002 from the markings on the power supply. Thanks once again.
Printone2

[printone2]

Re: Broken Dell 1800FP Power Supply - when and when not to resolder?

I have left the panel on for an hour at at time and the noise that was bothering me seems to have lessened and maybe it is just normal for this panel. I am going to take my chances and leave this on for a day and see how it goes.
Printone2

[printone2]

Re: Broken Dell 1800FP Power Supply - ICE2AS01 voltage

As always Thanks Bill and Happy Holidays !!

The voltage was only about 6V twix pin 6 and 7. I also noted this board has a diode that reads 14 ohms either way, so I swapped in a board from another unit with an inverter problem and retested. This new board shows 11.6VDC at pin 6-7 on the same chip, and same at the SMPS output, and its still same 11.6VDC out of the logic to the separate inverter board. The dc output spec for this unit is supposed to be 12VDC. Is 11.6 OK, enough to do the job, or is something failing in power supply section knocking it down ?

Dan

I came across another 1800FP without power. I was about to order an ICE2AS01 (IC901), but did not find the pin 6 and 7 shorted. When I tested those pins with the mains on it only read 4.5VDC. This is not enough to drive this IC, I believe it needs upwards of 8.5VDC. It looks like I too have a diode and a couple of resistors that have failed. Parts are on order. I really enjoyed having a block diagram and a parts lists. Now to see if I read it correctly!

[PlainBill]

Re: Broken Dell 1800FP Power Supply - when and when not to resolder?

I have left the panel on for an hour at at time and the noise that was bothering me seems to have lessened and maybe it is just normal for this panel. I am going to take my chances and leave this on for a day and see how it goes.
Printone2

Based on reputation, Sam Young caps are 'replace on sight'.

PlainBill

[printone2]

Re: Broken Dell 1800FP Power Supply - ICE2AS01 voltage

I came across another 1800FP without power. I was about to order an ICE2AS01 (IC901), but did not find the pin 6 and 7 shorted. When I tested those pins with the mains on it only read 4.5VDC. This is not enough to drive this IC, I believe it needs upwards of 8.5VDC. It looks like I too have a diode and a couple of resistors that have failed. Parts are on order. I really enjoyed having a block diagram and a parts lists. Now to see if I read it correctly!

Well it looks like I may have read the diagram correctly, but the panel still would not work until I swapped a known good ICE2AS01 (IC901) on the power board. I guess I get to order those too. Thanks.

[auroraborealiss]

Re: Broken Dell 1800FP Power Supply - when and when not to resolder?

Bobdee, thank you very much. I almost cried when I saw the manual - Actual Schematics!!!!

PlainBill

how can i get you to send me those images?

[PlainBill]

Re: Broken Dell 1800FP Power Supply - when and when not to resolder?

how can i get you to send me those images?

You can't, you will have to get them for yourself. Follow the link in post 33.

PlainBill