Neovo F-419 no power.

[playman]

Re: Neovo F-419 no power.

Shoot!!! That indicates the resistor is good. Check R822, please.

R822=814 or 814kohm, wich is well with in the 5% tolerance.
I put it back in and checked a reading between them and got 1491kohm

Some parts are 'jelly bean' parts - available from multiple companies and interchangeable. For decades the standard resistor used in electronics was a 1/2 watt leaded carbon composition resistor with a 20% tolerance. As electronics moved away from vacuum tubes, current demands dropped, and better materials became available this evolved to the 1/4 watt metal film 5% tolerance leaded resistor. With surface mount, the standard resistor is now a 1/8 watt metal film SMT resistor.

To answer your question, all of the other components that look like R821 and have an R designation are resistors; the only difference between them would be the resistance. R821 should have the numbers 684 on the top - 68 followed by four zeros, or 680000 ohms, or 680K ohm. I'll let you tell me what a 470 ohm resistor would say.

PlainBill

I was going to say HAH you just gave me the answer earlyer, was going to say well ofcourse 470kohm,
then,
hey wait a minute what's that 0 there, so i'm guessing it's 0-1-2-3-etc..
so a 470 would give me 4.7kohm? (man I have no idea how I got that number lol)
but then as I was not 100% sure so I checked the net and 470 should be 47ohm right?

Acording to this site http://www.electronicrepairguide.com...stor-code.html
those SMD's are just like the color resistors except they use numbers instead of color code?
SMD and SMT are the same?

[PlainBill]

Re: Neovo F-419 no power.

R822=814 or 814kohm, wich is well with in the 5% tolerance.
I put it back in and checked a reading between them and got 1491kohm


I was going to say HAH you just gave me the answer earlyer, was going to say well ofcourse 470kohm,
then,
hey wait a minute what's that 0 there, so i'm guessing it's 0-1-2-3-etc..
so a 470 would give me 4.7kohm? (man I have no idea how I got that number lol)
but then as I was not 100% sure so I checked the net and 470 should be 47ohm right?

Acording to this site http://www.electronicrepairguide.com...stor-code.html
those SMD's are just like the color resistors except they use numbers instead of color code?
SMD and SMT are the same?

You are correct, it's 47 ohm. And SMD and SMT are used interchangeably, although I suppose one is preferred, I just don't know (or care) which.

This of course doesn't help explain the original problem, so lets see if we can figure out what is going on with the SMPS controller. To that end, I've crudely marked up your picture of the bottom of the power supply, labeling a few points of interest.

V- is the negative side of the rectified AC, V+ is the positive side. I believe you indicated that was 320 volts. I've also marked the rough boundaries of the hot side of the SMPS in yellow. Lastly, I've numbered the SMPS controller in orange - assuming the lower right corner is pin 1.

With AC power disconnected and the DMM on the 200 ohm range, what is the resistance between V- and U801, pin 1? Between V- and U801, pin 3? Between V- and U801, pin 6? Between the upper end of R821 and U801, pin 3?

PlainBill
Wit

[playman]

Re: Neovo F-419 no power.

Yes you labeled pin1 correct.
V- to U801 pin1 =0.9
V- to U801 pin3 = no read
V- to U801 pin6 =1.2
R821 to U801 pin3 = 0.9
did not get any reading past R821

Ps.
Is there any way to make my crapy DMM better?

[PlainBill]

Re: Neovo F-419 no power.

Yes you labeled pin1 correct.
V- to U801 pin1 =0.9
V- to U801 pin3 = no read
V- to U801 pin6 =1.2
R821 to U801 pin3 = 0.9
did not get any reading past R821

Ps.
Is there any way to make my crapy DMM better?

The resistance readings are what I would expect. Next, let's try voltage measurements. All readings will be made with the black probe on V-. Rather than specify the voltage range to use, set the meter to the 1000 VDC range, then go to the next lower range if the reading is within that range. (For example, you measure the voltage on U801, pin3. It reads about 160 volts, Reduce the range to the 200 VDC range and measure again.)

Now plug in the power cord and carefully make these measurements.
V- to U801 pin1
V- to U801 pin3
V- to U801 pin6

The best way to make a crappy DMM better is to sell it and buy a new one. Recently we have had a few cases where the problem was the 'organism' holding the probes.

PlainBill

[Rtech]

Re: Neovo F-419 no power.

Recently we have had a few cases where the problem was the 'organism' holding the probes.

PlainBill[/QUOTE]

Gave me a good start to the day,thanks Bill.

[playman]

Re: Neovo F-419 no power.

V- to U801 pin1 = 0v
V- to U801 pin3 = 3.32v on 20VDC
V- to U801 pin6 = 0v
I started @ 600VDC and went down to 20VDC
Used the black probe on V- and Red on U801

The best way to make a crappy DMM better is to sell it and buy a new one. Recently we have had a few cases where the problem was the 'organism' holding the probes.

And I laughed

[PlainBill]

Re: Neovo F-419 no power.

V- to U801 pin1 = 0v
V- to U801 pin3 = 3.32v on 20VDC
V- to U801 pin6 = 0v
I started @ 600VDC and went down to 20VDC
Used the black probe on V- and Red on U801


And I laughed

I'm having a problem getting my head around the readings you have gotten at various times on the V+ to U801 pin 1 path. Still, this looks very much like U801 has failed. I'd say it's time to replace it.

PlainBill

[playman]

Re: Neovo F-419 no power.

Still, this looks very much like U801 has failed. I'd say it's time to replace it

That's a shame, it will be interesting how it will go when I try to solder the new one in, there are so small solderings on it lol.

It might take some time to get the part.
what should I do after I have replaced it? just put it to gather and test the screen?

BTW do you know of some good newbie soldering 101 site, i've found some but none that were good enough.

[alexanna]

Re: Neovo F-419 no power.

Buy some Chip Quik for Digi-Key it makes removing the small IC a snap.
When you solder the new part in coat the pads and pins with flux, Then with a fine tip soldering iron melt some solder on the tip, and like you are drawing a line with a pencil start at the solder pad and drag the solder to and on the pins of the IC.

[retiredcaps]

Re: Neovo F-419 no power.

BTW do you know of some good newbie soldering 101 site, i've found some but none that were good enough.

CuriousInventor has excellent videos

http://www.youtube.com/watch?v=3NN7UGWYmBY

[BobMollie]

Re: Neovo F-419 no power.

Is this thread still going. I have a power issue with a Neovo F419 also. The only problem is that my board layout is different the what is being shown here.

[budm]

Re: Neovo F-419 no power.

Is this thread still going. I have a power issue with a Neovo F419 also. The only problem is that my board layout is different the what is being shown here.

So show us good clear and focused pictures of your boards to start with.

[BobMollie]

Re: Neovo F-419 no power.

Here are some pictures of the power supply board and the logic board. The unit does not turn on nor does the LED power light. I do have 167 volts across C805.

[BobMollie]

Re: Neovo F-419 no power.

I have read the articles. Does anyone have a schematic of this board, or any info on the board?

[budm]

Re: Neovo F-419 no power.

What DCV do you have at the white connector that has the cable going to the Logic board (disconnect the cable to the logic board first)?

[BobMollie]

Re: Neovo F-419 no power.

I have 0 volts on everything except the Green had 0.017 vdc and the Blu had 0,05 vdc.

[BobMollie]

Re: Neovo F-419 no power.

budm are u their?

[budm]

Re: Neovo F-419 no power.

So it is dead without the logic/main board connected.
You will need to check the rectifier diode D841 mounted on the heatsink and D842 to ake sure they are not shorted. If they are OK, then we need to find out if there are shorted circuit in the inverter section.
I will need good clear pictures of the bottom side of the board.

[BobMollie]

Re: Neovo F-419 no power.



Budm, Diodes D841 and D842 test ok. See the foil side of the two circuit boards.

[BobMollie]

Re: Neovo F-419 no power.

Budm are you their.