Voltmeter load

[Bret burrill]

OK thank you. I'm going to see what they have now.

 

[Bret burrill]

Well they had only one regulator that output 12v. They had packs of assorted capacitors for cheap, but I didn't know if I should buy disc type or electrolytic. I'm going to Fry's now to see what they have.

 

[Bret burrill]

I got thermal grease, 4 capacitors 1uf 100v non-polarized electrolytic and two positive voltage regulators. This stuff is NTE brand, so if it is junk let me know so I can throw it out and get good stuff. I also ordered the oscilloscope. Thanks for pointing me in this direction, I'm looking forward to using this.

 

[Perry Babin]

NTE is overpriced and can lead to problems, especially in class D amps but for this, they will be perfectly fine.

Go to youtube and watch some of the various videos on how to operate the scope before it arrives.

 

[Bret burrill]

Good to know for future reference. I don't know the first thing about a scope, so youtube sounds like a good idea.

 

[Perry Babin]

Try page 73 of my car audio site for basics and to understand what the controls do.
Oscilloscope

 

[Bret burrill]

The oscilloscope arrived in pieces, broken in other words. The idiots that sold it shipped it in an envelope. This keeps happening to me. The last two amps I bought were damaged in shipping and, believe it or not, the ms-275 I bought was shipped in a god damn envelope! People need to get a clue.

 

[Perry Babin]

They may just send you another one and tell you to keep this one. Ebay will make sure you don't get ripped off.

 

[Bret burrill]

I used Amazon, so maybe the same deal. It would be awesome if I ended up with two since I was just given a broken amplifier to try and repair. One scope I definitely want permanently installed in my car.

 

[Bret burrill]

I'm unable to return this scope to Scamazon, so I'm adding it to my ridiculously long to do list. I got me a 9v power adapter and hooked this up and got a blank white screen. There are two sets of lcd module connectors on the display board. Wouldn't it stand to reason there should be continuity between these two sets? I get continuity between all pins except 38, 39 and 40. On the diagram there is a 'less than' symbol for these, what is the meaning of that? Could this be my problem? The other variable is the power supply. Its 9v 1000ma DC out. I have no idea if this is good to use. If I can get this working I still plan to install it in the dash of my car.

 

[Perry Babin]

The white display likely means it's not booting up. Did you go through and check all of the various voltages to see if any were missing?

 

[Bret burrill]

There was an MCU test I performed. After pressing reset the led blinks twice, so that is good. I'll check voltages now.

 

[Bret burrill]

The voltage at the point where the adapter attaches is just over 9 volts. Everywhere else its 0v or close to it. I checked a random regulator and it was getting good voltage in but putting out nothing. I am out of money for parts now and have too many projects so this might have to go on ebay for $5.

 

[Perry Babin]

Are you sure that the polarity of the adapter is correct for the scope?

How did the reset test work if there is no voltage anywhere?

Is D2 installed correctly?

 

[Bret burrill]

Yes its center positive. I actually tried two adapters. The first adapter gave me voltage all over the board but it stopped working. The second adapter is the one I have hooked up now that is giving me nothing. I think there was something wrong with the first adapter and it fried something. The first was 1000ma the second is 500ma.