Search found 373 matches

by psycho
Tue Oct 14, 2008 3:58 pm
Forum: General Discussion
Topic: 7yr old + battery + developement board = smokebomb
Replies: 19
Views: 3603

Update... The heat gun Mfg. was wrong. I tried with a soldering iron and got nowhere fast. That was last week. Today I was fixing a cellphone charger whose cord seemed to fascinate our 6 month old kitten and was finishing up the heat shrinking. I glanced over and saw the board and figured I would tr...
by psycho
Tue Oct 14, 2008 11:39 am
Forum: General Discussion
Topic: A question about a schematic
Replies: 18
Views: 3637

Update... In looking at the schematic, the 1.5KE400c is not on it. it goes from the center pin of J5 to the positive end of C570. And it was desoldered when I tested it. There are a couple other things on the PCB that are not on the schematic. One is a motorola part between pin 2 & 7 of the PWM IC. ...
by psycho
Tue Oct 14, 2008 10:01 am
Forum: General Discussion
Topic: A question about a schematic
Replies: 18
Views: 3637

Q26, 27, & 28 are bad. This is what I used for checking the MOSFETs (Q24 & Q25): http://www.uoguelph.ca/~antoon/gadgets/mostest.htm Mouser has the @2SK809's (Q24 & Q25) here: http://www.mouser.com/Search/Refine.aspx?Keyword=2sk809&Ns=P_SField D578 (MUR880) conducts in both dirs. and there is a 1.5KE...
by psycho
Tue Oct 14, 2008 8:39 am
Forum: General Discussion
Topic: A question about a schematic
Replies: 18
Views: 3637

Bigglez, Thanks for the info. I have run some tests and found all of the transistors to be bad. Not sure about the mosfets because my meter only puts out 2.7v and I read that you need at least 3.3v. I did check all the pins and it they do not conduct in any pin configuration. Nice, but I don't think...
by psycho
Mon Oct 13, 2008 4:26 pm
Forum: General Discussion
Topic: A question about a schematic
Replies: 18
Views: 3637

Bigglez, I believe my Taito Arcade cabinet has an Isolation transformer. I shall look into it. I was planning to use a light (say 40 watts) in series to limit the current to the SMPS when I finally test it. This may sound stupid, but, I have a scope. I have never measured anything over about 5 volts...
by psycho
Mon Oct 13, 2008 2:50 pm
Forum: General Discussion
Topic: A question about a schematic
Replies: 18
Views: 3637

I accidentally put 240 into it when it was setup for 120. I am hoping that there is nothing behind the transformer that is bad (including the xfrmr itself). Whats worse is that when I did it, like a dumba**, I bypassed the fuse and tried it again. Popped a few traces and I am sure the PWM chip took ...
by psycho
Mon Oct 13, 2008 12:19 pm
Forum: General Discussion
Topic: A question about a schematic
Replies: 18
Views: 3637

A question about a schematic

If you know anything about SMPS's, would you be able to take a look at this: http://kevin.zee-family.com/schematics.pdf on page 4 of it, and answer a question for me. Right by the bridge rectifier is a jumper which is used for 120/240v selection. In my thinking, which is probably wrong, if this jump...
by psycho
Mon Oct 13, 2008 12:30 am
Forum: General Discussion
Topic: taillight converter - the other way
Replies: 14
Views: 3439

If it is the same problem I've had then it is a broken filament in one of the dual filament light bulbs. The 1157, 2057 and equivalent have a filament for the tail light (on when the headlights are on) and the brake/turn signal filament. One of the filaments failed and shorted to the other on the l...
by psycho
Thu Oct 02, 2008 10:32 am
Forum: General Discussion
Topic: 7yr old + battery + developement board = smokebomb
Replies: 19
Views: 3603

Yeah. That is the board. I heard back from the heat gun mfr. and the gun only goes to about 400*F so I am not sure it will work.

Kevin

-edit-
My son definitely did learn a little bit about the magic smoke that is contained in all those parts. He loves watching over my shoulder while I work.
-
by psycho
Wed Oct 01, 2008 5:37 pm
Forum: General Discussion
Topic: 7yr old + battery + developement board = smokebomb
Replies: 19
Views: 3603

So, if my thinking is correct, I would put the zener in series? I have never used a zener for this...

Thanks,
Kevin
by psycho
Wed Oct 01, 2008 3:51 pm
Forum: General Discussion
Topic: 7yr old + battery + developement board = smokebomb
Replies: 19
Views: 3603

Yeah. I will try the heat gun. I know the gun works great for shrink tube. Dunno if it will get hot enough for this, though. I have some 5.1v zeners. I will have to throw one of them in there. What do you think the odds are that the gun will heat up enough? haklesup: Actually it is a microchip 44pin...
by psycho
Wed Oct 01, 2008 2:17 pm
Forum: General Discussion
Topic: 7yr old + battery + developement board = smokebomb
Replies: 19
Views: 3603

7yr old + battery + developement board = smokebomb

He hooked it up backwards. He didn't know why it wasn't doing what it should have so he waited. Poof. At least he didn't get hurt. Blew the pic (at a minimum). It's a 16F887 surface mount. I am gonna desolder and replace it but, I have never had to desolder any SMT ICs. I can't snip the pins like I ...
by psycho
Mon Aug 25, 2008 7:33 pm
Forum: General Discussion
Topic: A new PIC Disassembler
Replies: 0
Views: 1049

A new PIC Disassembler

I have finally released a beta version of PicItApart. It is an Interactive PIC Disassembler. You can get it here :

http://picitapart.zee-family.com

It will do 12 & 14 bit cores (almost 200 devices)

Kevin
by psycho
Fri Aug 15, 2008 3:44 am
Forum: General Discussion
Topic: Headphone question
Replies: 4
Views: 1210

I doubt you will find scematics for the sansa but, this one looks interesting :

http://www.pjrc.com/mp3/schematic_revc.html

If you google "mp3 player" +schematics you will find quite a few hits for ideas on how they are made.

Kevin
by psycho
Thu Aug 14, 2008 2:15 pm
Forum: General Discussion
Topic: Headphone question
Replies: 4
Views: 1210

That will just about do it :)

Thanks,
Kevin