Sanyo DP42849 - No Power At All

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

DCV 20

IC1660 - Pin 5 = 0.27

Which pin is pin 1 on 1630 and on Q1651?

[tom66]

Re: Sanyo DP42849 - No Power At All

IC1660 should be primary focus for now.

Pin 1 of devices should be marked with a "1" or small dot in plastic.

Check voltage pin 4 of IC1660.

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

Here's R1684. Not sure where to put probes.

I'm not seeing any numbers near the pins, and I can't see any dots in the plastic for 1630 and Q1651.

I'll check pin 4 on IC1660.

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

IC1660 - Pin 4:

When I first put probe on it with TV plugged in, I got .09. Touched it for ~80 seconds, and it climbed slowly to .18.

Touching power button resulted in no change.

Just to be clear, this is IC1660?

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

Probed what I assume is pin 3 on the Sharp IC. Got 0.

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

What is the next step?

Thank you.

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

Did I test IC1660 correctly?

[tom66]

Re: Sanyo DP42849 - No Power At All

No, it's me whose forgotten to check this thread. Yes, you tested it fine. I think the power board is at fault. Do you get anything on the 15V or 24V pins when you try and power it up? I forgot to mention checking those would be an idea.

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

No worries! You've gotten us pretty far already, man. I'd be lost without you.

I have tried checking those pins over and over again, trying to do it correctly, and I can't get anything. Obviously I'm doing it wrong, or I'd least see 5V, right?

I've got class, but I will try again when I get home this evening.

Thank you.

[tom66]

Re: Sanyo DP42849 - No Power At All

You might want to try using a wire in the pin hole and probing the wire instead. Also, check your ground point is actually ground, and not isolated.

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

I'll try that.

What should ground read if it's working proper?

Actually, where should I put my probes to check ground?

[tom66]

Re: Sanyo DP42849 - No Power At All

You can try one of the screws on the cold/secondary side of PSU, or the main board.

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

Just the black probe to a mounting screw? What should I have my meter on?

[tom66]

Re: Sanyo DP42849 - No Power At All

No, that's just where to use for ground. If you want, you can do an ohms test to the outer metal of the RCA jacks, which are good ground points.

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

Sorry, I'm a little confused. How to I check if something is properly grounded?

There's a little hole in the chassis next to the main board - when doing the IC1660 tests, I just stuck my black probe in there for ground.

[tom66]

Re: Sanyo DP42849 - No Power At All

Put one probe on the RCA jack outer shield, this is a known good ground. Put the other probe on an unknown ground point. With meter on the 2000 ohm range, note reading. Lower than a few ohms indicates a good ground point.

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

Okay, maybe I've misunderstood what a mounting screw is. I thought it was any screw that held the board in place? Apparently that isn't the case.

So with one probe on an RCA jack, and the other on a suspected ground point, here's what I got:

Hole in chassis - < 002
Any screw holding up main board - < 002
Top right screw in power board - I get a negative reading of (-002)
Bottom left screw in power board - < 002

All other screws in power board - Stays at "1".
Recessed metal in-between the two boards - Stays at "1".

The screw on the power board I've been using as ground stays at "1".

[tom66]

Re: Sanyo DP42849 - No Power At All

Looks like you need to re-evaluate your ground point to a point reading "002".

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

You're right! I just got 4.99 on 5VSTB. I guess I just assumed any screw would work.

I'll redo all pin voltages.

. . . does this mean I've ruined things while testing them?

[tom66]

Re: Sanyo DP42849 - No Power At All

It means the voltages weren't accurate so you/we have been chasing a wild goose.
Put it down to my fault for not clarifying what ground point is and your fault for not asking .