MPF6908 No 5V on pin 6 to A Board

[LITEZONER]

Re: MPF6908 No 5V on pin 6 to A Board

Hate to tell you, but i got the part number from someone selling the whole board on ebay, i could not locate that particular one, so i subed the next size up, all the specs are the same exept the voltage is 50 instead of 25, this is the correct part number that the person with the board gave me. ERZV10D621 Varistors 620V 2500A ZNR SUR ABSORBER 10MM

[LITEZONER]

Re: MPF6908 No 5V on pin 6 to A Board

I just located the correct one at mouser, wish i checked before. I just did not think it would make a big difference since the specs were identical, I did replace the fet Q101 as well, and it still tests good, that one is really hard to find.

[budm]

Re: MPF6908 No 5V on pin 6 to A Board

Hate to tell you, but i got the part number from someone selling the whole board on ebay, i could not locate that particular one, so i subed the next size up, all the specs are the same exept the voltage is 50 instead of 25, this is the correct part number that the person with the board gave me. ERZV10D621 Varistors 620V 2500A ZNR SUR ABSORBER 10MM

OK, are you talking about the NTC001? If he gave you that P/N of the VARISTOR (MOV, or surge suppressor) for the NTC then he does not know what NTC is and needs to go back to school. There are three MOVs on that power supply board, Z001, 002, 003.
Then you have NTC001 which IS NOT MOV!
MOV IS NOT same as NTC.
'so i subed the next size up, all the specs are the same exept the voltage is 50 instead of 25" Not only you should not change the Voltage rating, the clamping Voltage is VERY important, the diameter can be larger for higher Jules rating but you should NOT change the Voltage rating of the MOV.

[budm]

Re: MPF6908 No 5V on pin 6 to A Board

Stby ps.

[LITEZONER]

Re: MPF6908 No 5V on pin 6 to A Board

budm, Thank you, Huge help on this, i will order the corrected NTZ and replace MOV's, I have to order parts, so i ill post results then. The three MOV's don't show any signs of failure, so I should start with corrected NTZ? Thanks again.

[LITEZONER]

Re: MPF6908 No 5V on pin 6 to A Board

I think the correct one it the top one here, can you verify please? Thank you

http://www.mouser.com/Circuit-Protec...10D621&FS=True

[budm]

Re: MPF6908 No 5V on pin 6 to A Board

'budm, Thank you, Huge help on this, i will order the corrected NTZ and replace MOV's, I have to order parts, so i ill post results then. The three MOV's don't show any signs of failure, so I should start with corrected NTZ? Thanks again.'

NTC, NOT NTZ. BTW, What numbers are printed on the body of those 3 MOVs, and on the body of the NTC001?
If those 3 MOVs do not show as shorted circuits then you do not need to replace them. All three MOVs can be removed and the circuit will still function, they are for protection not for the operation of the circuits.
For now what you can do is to use 1A fuse in place of the NTC for testing purpose.
That red NTC001 which you said it shows as open circuit, it should show the sign of damages. So are you sure the NTC001 show open circuit? What DCV do get measure between the two legs of C102?

[LITEZONER]

Re: MPF6908 No 5V on pin 6 to A Board

3 MOV's are ZNR V10621U with no visible damage, NTC001 IS a ZNR V14621U, 0 DCV across cap at C102, Here is what i think, I was given incorrect information as to the replacement of NTC, it was red and visibly damaged, The ZNR number above is a MOV, and this location NTC should not be an MOV correct? So I believe what i need is correct component for NTC001. (I will pick up a 1 Amp fuse and try it)

[budm]

Re: MPF6908 No 5V on pin 6 to A Board

"Here is what i think, I was given incorrect information as to the replacement of NTC, it was red and visibly damaged, The ZNR number above is a MOV, and this location NTC should not be an MOV correct?" You got it! I still believe you do have something bad in that standby power supply section that causes the NTC to be damaged.

[LITEZONER]

Re: MPF6908 No 5V on pin 6 to A Board

well Budm, you are correct, I have no more short condition, board accepts AC without blowing any of the now 3 fuses, at C102 I still do not get DCV if flashes voltage for a very brief moment but is gone in less than a second. I get no resistance at any of the three MOV's it is open, But i suspect they are voltage dependent.

[budm]

Re: MPF6908 No 5V on pin 6 to A Board

"I get no resistance at any of the three MOV's it is open," They good.
So did you put a fuse in place of the NTC001, if you did then you should have 160~170VDC on that C102 which is the filter cap after the D006.
You also need to check the fusible resistor R802, 803, 804.

[LITEZONER]

Re: MPF6908 No 5V on pin 6 to A Board

yes on the fuse, still don't have any idea what part goes there, but it's not blowing any fuses. R802,3,4 flash the forward voltage for a micro second, same as all the other one's i tested as well. would the incorrect size diode be a factor in D011 and D006, I think that if it were too small it would just blow? They test fine, so never mind that one, I am going to plug it in and pray as i trace line voltage across all the components to see where it stops, when testing AC where is a good place for the black lead,? where i can just fallow one main at a time. Thank you .

[LITEZONER]

Re: MPF6908 No 5V on pin 6 to A Board

I guess just clip it on the neutral line?

[budm]

Re: MPF6908 No 5V on pin 6 to A Board

" R802,3,4 flash the forward voltage for a micro second" What do you mean? we are measuring the resistance of those fusible resistors, not Voltages.

'yes on the fuse," What does that mean?

[budm]

Re: MPF6908 No 5V on pin 6 to A Board

I guess just clip it on the neutral line?

Why do you want to do that?
I am really not sure what you are doing.
The reason you replaced D011, D006 because they are tested as bad?

[LITEZONER]

Re: MPF6908 No 5V on pin 6 to A Board

The 1A fuse you suggested i could use I did, it is in place in the NTC001 location, I get 0 resistance on these, I tried several ranges R802, R803, R804 Yes D011 and D006 were bad

[budm]

Re: MPF6908 No 5V on pin 6 to A Board

"I get 0 resistance on these, I tried several ranges R802, R803, R804" so they are good. I expect them to show very low resistance.
I do not know why you are not getting DCV on the two legs of C102.
Try measuring the ACV between the Anode of D006 and the negative leg of C102.

[LITEZONER]

Re: MPF6908 No 5V on pin 6 to A Board

Okay, Pos lead on anode, neg lead on neg leg of C102 reads 117V AC, If i reverse the leads it starts out at 107 and starts going downward in AV Voltage.

[budm]

Re: MPF6908 No 5V on pin 6 to A Board

"Okay, Pos lead on anode, neg lead on neg leg of C102 reads 117V AC" That is what I expect, so we have AC feeding the D006, the fuse is in place of the NTC, C102 is in place but you are saying you have 0VDC between the two legs of C102, this is an impossible measurement. It is just a simple rectifying circuit.

[LITEZONER]

Re: MPF6908 No 5V on pin 6 to A Board

I am so sorry, i am getting 165DCV Across C102, I am an idiot I had my meter on incorrect range, i am going to go stick my tongue in a light socket for punishment.