VP2030b Power Supply Problem

[chrisuk]

Hi. Just joined the forum today. Looks like there is a wealth of information here. Can anyone help with the repair I'm trying to make to my VP2030b Power Supply Board type EADP-64BF B. Its blown a capacitor on the mains input side. Its marked up on the board as "NTC1" and is connected across the Neutral (I'm in the UK) and a small inductor. It was covered in a rubberized sleeve and is blown to bits so I can't read what it is. More info is that it is green and about 10mm diameter. I have managed to identify two letters on it "CK" and underneath the "K" was the number "4". Any help would be gratefully received.

Chris S.

[Rtech]

Re: VP2030b Power Supply Problem

Its a thermistor see below;
http://www.alldatasheet.com/datashee...SCK05052L.html

[ben7]

Re: VP2030b Power Supply Problem

Hi. Just joined the forum today. Looks like there is a wealth of information here. Can anyone help with the repair I'm trying to make to my VP2030b Power Supply Board type EADP-64BF B. Its blown a capacitor on the mains input side. Its marked up on the board as "NTC1" and is connected across the Neutral (I'm in the UK) and a small inductor. It was covered in a rubberized sleeve and is blown to bits so I can't read what it is. More info is that it is green and about 10mm diameter. I have managed to identify two letters on it "CK" and underneath the "K" was the number "4". Any help would be gratefully received.

Chris S.

That is an NTC inrush current limiter.

The PSU fuse is also likely blown - and there could also be a shorted bridge rectifier, and/or a shorted MOSFET, or shorted filter capacitor.

[chrisuk]

Re: VP2030b Power Supply Problem

Hi ben7 & Rtech. Wow fast response. Thank you very much. Just shows a little knowledge can be dangerous (on my part). I have been working on this for a few days now and have already replaced a 150mF capacitor and a 2SK3569 MOSFET (and yes the fuse has blown several times while trying it out). I'll order one of these from RS Components and see what happens. Thanks again.

Chris S.

[chrisuk]

Re: VP2030b Power Supply Problem

Hi again.

Should have realised I have no idea which thermistor/inrush limiter I should be ordering. Do you have any idea which part would be used in this power supply. I have the data sheet but I don't know what characteristics I need.

Chris S.

[Rtech]

Re: VP2030b Power Supply Problem

Hi again.

Should have realised I have no idea which thermistor/inrush limiter I should be ordering. Do you have any idea which part would be used in this power supply. I have the data sheet but I don't know what characteristics I need.

Chris S.

https://www.badcaps.net/forum/showth...t=14892...Post 2

[chrisuk]

Re: VP2030b Power Supply Problem

Thanks Rtech.

[chrisuk]

Re: VP2030b Power Supply Problem

Hi, its been a while (work committments) but I'm back on the case of my broken VP2030b.
I had narrowed the problem down to the power supply and have replaced various components and it no longer blows up when I put power on to it. So far i've replaced the components mentioned in the thread but its still dead when I put the monitor together. I don't really know how to test the power supply but when its powered up on its own I don't seem to have anything past the new
2SK3569 MOSFET. If anyone has any ideas on how I could identify where the problem is now I would appreciate any help on offer.

[Rtech]

Re: VP2030b Power Supply Problem

Chris,We are at the 'show us some photos' stage.Submit via the 'Go Advanced',shown below and then 'manage attachments.Good clear,focused ones of both top and bottom.

[chrisuk]

Re: VP2030b Power Supply Problem

Hi RTech. I've attached two pics top and bottom as requested. I should point out that I repositioned one of the capacitors when I tried to fit a replacement 400V 150mf capacitor which wouldn't fit in the end so I bought the correct size but left the re-positioned capacitor in its new position. There is also a track repair under the MOSFET area (the other wire link is for the repositioned capacitor. If you could tell me what to check with the board on the bench, I do have test equipment if it helps. Thanks.

[Rtech]

Re: VP2030b Power Supply Problem

The DC Voltage acorss the big cap, should be 330V approx ?? if that is correct then we need to look at IC 1,but cannot find a datasheet at the moment !!

[chrisuk]

Re: VP2030b Power Supply Problem

Yes, 330V across the big cap confirmed.

[selldoor]

Re: VP2030b Power Supply Problem

Did you check the black box 4A fuse

[chrisuk]

Re: VP2030b Power Supply Problem

Hi selldoor. I just checked it in situ and I have continuity so I think its OK (unless i need to take it out of circuit)?

I've been trying to find a datasheet for IC1 (DAP08) online but no luck up to now!

[Rtech]

Re: VP2030b Power Supply Problem

As this datasheet seems to be impossible to find ! then suggest you Measure resistance on it.The negative lead of your meter to the negative leg of the big cap,and resistance then to each of the pins,POWER OFF of course.One pin should be gnd,Pin 7 looks like its not connected(which is normal on some of these).Also on the Top of the board just above one of the markings saying +20v,is an optocoupler,and a Cap,and purely from its location,I suspect that is the start up Cap,and attached to that usually on the top also, is the negative side of a diode,maybe via a resistor,and the feed comes from the transformer.If the cap is faulty OR the diode leaky then IC 1 will not get a Vcc voltage to allow it to start up.

[jetadm123]

Re: VP2030b Power Supply Problem

I believe the DAP08 is a NCP1203d6 controller. You can download the datasheet to see if the pins match up.

[chrisuk]

Re: VP2030b Power Supply Problem

Looks like you may be right Jetadm123 the pins look right.

Rtech, I've checked the components you mentioned and they all seem OK. I have diode and capacitance functions on my multimeter (Fluke 185) and the capacitors and diodes checked out OK I think. Also I actually powered up the board and measured 3.6VDC betweens pins 4 (ground) & 6 (VCC) according to the NCP1203 pinout. Any help?

[chrisuk]

Re: VP2030b Power Supply Problem

Here's a pic of the NCP1203 pinout if it helps.

[jetadm123]

Re: VP2030b Power Supply Problem

Looks like Vcc has to be at least 12.8VDC for the NCP1203 to turn on. There should be a small startup cap 22uf-47uf 50V connected to Vcc. Has it been changed?

Was the 2SK3569 connected to the NCP1203? When it shorted out, it may have taken the NCP1203 with it.

[chrisuk]

Re: VP2030b Power Supply Problem

The 22uf capacitor hasn't been changed but appears to check out OK on the multimeter (it's reading 22uf across the terminals while in circuit). I am starting to think the NCP1203 might be gone. Should I remove it and check to see if I get the 12.8VDC at the pin 6 tab?