Log in
Register
Menu
Log in
Register
Home
What's new
Latest activity
Authors
Forums
New posts
Search forums
What's new
New posts
Latest activity
Members
Current visitors
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Forums
Miscellaneous Sections
Tech Head - The Technology Section
The Work Bench and Soldering Station
Faulty 0/12v output?
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="Llew" data-source="post: 282812" data-attributes="member: 175007"><p>OK, may be duff, but would be a good idea to check through the associated circuitry from the source (not much to it).</p><p></p><p>This will be a PIO4 output of the processor, which terminates at the bottom leg of R83 (just below and to the right of the transistor. This is 3.25V (12V on) and 0V (12V off).</p><p></p><p>The top leg of that resistor will be 0.7V (12V on) and 0V (off).</p><p></p><p>This goes to the bottom left leg of the adjacent transistor Q14.</p><p></p><p>With 12V on, the top leg of Q14 should be 0V, 12V off, will be 12V.</p><p></p><p>This goes to the first transistor bottom left leg via R76 to do the switching.</p><p></p><p>Sorry if that seems a bit convoluted, but that's all there is to the switching circuit.</p><p></p><p>As long as the processor is switching OK, it's got to be one of those two transistors that have failed. (Unlikely to be a resistor).</p><p></p><p>Llew</p></blockquote><p></p>
[QUOTE="Llew, post: 282812, member: 175007"] OK, may be duff, but would be a good idea to check through the associated circuitry from the source (not much to it). This will be a PIO4 output of the processor, which terminates at the bottom leg of R83 (just below and to the right of the transistor. This is 3.25V (12V on) and 0V (12V off). The top leg of that resistor will be 0.7V (12V on) and 0V (off). This goes to the bottom left leg of the adjacent transistor Q14. With 12V on, the top leg of Q14 should be 0V, 12V off, will be 12V. This goes to the first transistor bottom left leg via R76 to do the switching. Sorry if that seems a bit convoluted, but that's all there is to the switching circuit. As long as the processor is switching OK, it's got to be one of those two transistors that have failed. (Unlikely to be a resistor). Llew [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Miscellaneous Sections
Tech Head - The Technology Section
The Work Bench and Soldering Station
Faulty 0/12v output?
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
Accept
Learn more…
Top