Also wanted to ask if this repair paint would work? After it cured just scrap away a small area around hole for solder to attach on. I never tried this stuff, but got it to repair boards.

 

So the UCC2804 is defective.

JB weld seems to be "steel reinforced" so I am not sure of it's electrical properties.

ehow recommends Loctite Hysol 0151 for pcb repair.

Timescope

 

So there should be continuity there or there shouldn't be?

 

Also wanted to ask if this repair paint would work? After it cured just scrap away a small area around hole for solder to attach on. I never tried this stuff, but got it to repair boards.

That's the green coating on the board (solder resist) that is used to cover areas of the board that do not need to be soldered and is not an adhesive.

Timescope

 

So there should be continuity there or there shouldn't be?

No, not as low as 600mV. We will use the new ic after checking all the remaining components and repairing the connections.

Which of the pins had rings disconnected ?

Timescope

 

Number 6 and number 3 had ones missing, but they dont go to anything on the schematic. and the underside of pin 1 which is just one of those free floating rings that dont connect to any circuits. So should I work on putting U2 back in?

 

So should I work on putting U2 back in?

No, not yet. Give me a few minutes to check some things out.

Timescope

 

Open the 102MB picture of the board and zoom in on UCC2804.

C16 is below the ic. Above C16 is a hole which should be connected to pin 6.

There is another hole on the right (near the silk screened "U3" and "C16).

These two holes are connected together and are the connection from pin 6 of the ic to R24 which is connected to the gate of the transistor.

Timescope

 

Yes that is correct, was I just to confirm that?

 

which is just one of those free floating rings that dont connect to any circuits.

I am concerned about the connections that you say do not go anywhere. Are the rings around a hole ?

Timescope

 

I am such an idiot!! I appologize agian, I thought we were talking about U3. As that was the last one we took off and they were threw hole connection. Pins 3 and 6 of U3 had small eyelets but didn't go anywhere. I think its just to help hold the component down. On the schematic they are labeled "NC1 and NC2" and dont connect to anything there as well.

 

So which ic had some connections lifted : MOC8102 or UCC2804 ?

Timescope

 

MOC8102 is the one that I was talking about. I called it U3 in the above post which is incorrect which I just caught. Sorry I am trying to do 2 things at once and I loose track which IC we are talking about. So it is "U2" which is the MOC8102 with 6 threw hole pins. Pin 3 and pin 6 are the ones that dont go anywhere and have a ring missing. So Im not too concerned with those. I cut some small pads out of that copper tape I bought and it worked nicely so far. I covered the hold and used a small awl to fold the copper in the hole and with an exact knife I trimmed it like the original one was like. The adhesive kept it in place and I tinned the pads with solder so when the IC goes in it will have an area to help hold it to the board.

 

Glad that's sorted out and the UCC2804 connections are ok.

Before you fix the ics and transistor back, cross check all the resistors and diodes.

Use your anti-static setup when you solder the new UCC2804.

The small indent on the ic marks pin 1. Refer to the 102MB picture to make sure that you have fixed the ic correctly.

Timescope

 

Yes UCC2804 was fine. Those just set on top of the board and I did what you said and it came right off.

So when I cross check all resistors and diodes, I will need to know if they are in series or parallel because one could be bad and giving the other a different reading just like the two 6r8 ones. Diodes the black test lead goes towards the stripe on the diode and positive on the other end and it should read the voltage going threw correct? And if the leads are reversed there will be no voltage, or a much smaller amount going threw.

My multimeter has capacitance as well as some kind of frequency position that I haven't used yet. Should I bother testing capacitors? Or would a bad cap not cause my problem? I have replaced bad caps before and usually they are leaking acid or bulging. These all look good. I also have a small pair of smd tweezers test leads if I need to test all the smd's on the board

 

With the ics and transistors out of the circuit, you should get accurate readings of the resistors because the only ones in parallel are the 6.8 ohms.

R19 and R20 will read about 1.34 k ohm because +8_KEY is at ground because C19 is discharged. This reading will rise as the meter charges C19.

You are correct about the diode test.

You may not get correct capacitor readings in circuit. Do not remove them to test as the heat may cause problems.

Timescope

 

Ok, I will do that tomorrow, its almost 10pm here and gona have dinner and head to bead. Do you ever sleep ?LOL Seems like you reply even during the day when it would be night time where you are.

 

It's 5am here and I will soon go to sleep for 2 or 3 hours.

The secret is black coffee.

Timescope

 

Ok did a bunch of testing just now and im getting inconclusive results.

On both of my multimeters it decides the ohm range for you. All but 3 resistors checked out right and if it was KΩ or just Ω the meeter would read correctly, except for these variances.
R3 is to be a 560Ω, Im getting .560kΩ
R17 is to be 470Ω, Im getting .470kΩ
R25 is to be 680Ω, im getting .675kΩ
I can manually select the range so it doesnt scroll threw them, and when I set it on just Ω it won't read anything at all. But when I let it decide it chooses to use kΩ and use a decimal point. Is there a reason for this? Is it normal? I checked it with another multimeter and same thing.

Now on the diodes something doesn't make sense at all, Ill try to explain it the best I can.

I know the negative probe goes on the striped end of diode and positive on the other.
D8, D9, D11, and D17 checked out this way. I would get .47mV with the leads this way and 000 when switched around.

D1,D2,D3= 527mV with leads the correct way, when reversed I get 1210mV
D12= 483mV correct way, reversed 1455mV
D13= 482mV correct way, reversed 1282mV
D15= 485mV correct way, reversed 1233mV
D16= 485mV correct way, reversed 1344mV

Does that mean all these diodes are bad?

 

So I got U2 back on and went to put on U3 and when I took it out of the package I noticed that there is no dimple to signify pin 1. At least that is what I have read the dimple means. Instead there is a strip like how the surface mount capacitors have on one end. I contacted digikey and they are looking into it. They say there should be a dimple like my old one. I checked the part number on U3 and its the same, so its the correct part. Gal at digikey said they could of changed it rather then forming the dimple in it they put a stripe. But the stripe goes across the end, so how do you know which is pin one? Only think I can think is to place the stripe the same direction the dimple is. There is only two ways it can go on, I just don't want to solder it on and have to remove the new one.