Small problem with possible easy answer

[Fear the Weasel]

Hey guys, just finished my core module board and tested the voltages.  Seems I am getting 6.4 Volts all round. 

I'm using a 9v  0.8mA DC power supply that mesures just that on J1 but at J2 I'm getting 6.4v instead of 5v so it's something in the starting stage.  Checked the board visually for shorts or anything but can't see any problems.  Capacitors and diodes are round the right way.

Maybe I fried one of the components when soldering?  Any ideas on the problem or how I could find it myself would be much apprieciated.  Kinda new to this electronics stuff, just hanging out to get it all going so I can get into the programming stuff!!

Cheers all!

[Twin-X]

do you get 9V of your power supply when measuring it?

I had something similar this was due to my multimeter not giving the correct values.

[Fear the Weasel]

Wow, fast reply!

I am getting 9v out of the supply and 9v off the connections to the board.

[Tanstaafl]

silly question on my part... but are you sure the voltage regulator is a 7805?

[Fear the Weasel]

sweet as, just glad someones interested in helping. :)  I got the core module as a kit from Smash TV so I'm pretty sure all the parts are the right ones.  Not sure what that leaves.  Faulty parts?  Faulty user?  ;)  Checked the soldering again but all seems good....

Sigh.  All part of the fun. :)

[smashtv]

silly question on my part... but are you sure the voltage regulator is a 7805?

hehe.....not a silly question at all!  I pulled a few kits from the same batch to make sure....The possibility for errors on my end is always there.  (but I do try to be accurate)

Hey guys, just finished my core module board and tested the voltages.  Seems I am getting 6.4 Volts all round. 

I'm using a 9v  0.8mA DC power supply that mesures just that on J1 but at J2 I'm getting 6.4v instead of 5v so it's something in the starting stage.  Checked the board visually for shorts or anything but can't see any problems.  Capacitors and diodes are round the right way.

Lets start with the power pack, I'm assuming here that it's actually 0.8A DC (800mA), .8mA won't run much or act well when connected.....

Are any of the parts in the power section getting hot?

The first two possibilities that come to mind (assuming external power is fine) are the bridge rectifier is in the wrong way, or the voltage regulator itself is inserted the wrong way.  I know this is probably something you have checked over and over already though.....

Maybe I fried one of the components when soldering?

This is possible.....and even likely if you use a super high wattage iron. ;)

What reading do you get between ground and pin 1 of the regulator?

Another thing is to try another power pack, some of them just don't work well with the core due to the design of thier own internal regulation (some give symptoms like this.....basically the switching hash interferes with the normal operation of the bridge rec.)

Don't worry, let's find the cause first so we can let others know what to watch out for, Then I'll send you out replacement parts (my cost) to get you going.

Best!

Smash

Almost forgot, email or pm me so I can associate you with your mailing address (I don't know my customer's forum names, I need to add a line to the order page for this.....)

[Fear the Weasel]

Hi there.  Sorted out the problem.  I had confused which pin of the voltage regulator was pin 1 so despite my multiple checkings I was making sure it was the wrong way round.   ::) Everything is reading proper voltages now.  Thanks heaps for helping guys, this really is a nice community of poeple. (offering to send me new components! - Cheers Smash TV!!) 

To summerise prob (in case you've got the same):

9v going in, J2 reads approx 6.4v instead of 5v. - Check which way round Voltage Regulator is.

Thanks guys!!

Should I change the title of this post to something more descriptive in case someone is searching for same answer?