Announcement

Collapse
No announcement yet.

User Profile

Collapse

Profile Sidebar

Collapse
Avatar
Longbow
Badcaps Veteran
Last Activity: 02-13-2024, 12:40 PM
Joined: 06-03-2011
Location: Dallas, TX
  •  
  • Filter
  • Time
  • Show
  • Source
Clear All
new posts

  • Need Schematic - NAD316 v2

    Need assistance finding a schematic for the NAD316 v2. This is the one with the phono preamp. (Yup, I know that v1 is commonly available).
    Thank you!
    LongBow
    See more | Go to post

  • Re: Dim Clock LCD on Jenn-Air wall oven

    I see that this specific subject has generated amazing interest over the years. Certainly, replacing electrolytics on the display pcb will bring back the Jenn Air (and others) display brightness.


    However...these things are getting old by anyone's standards, so we have to be practical and realize that the VFD (the display tube itself) slowly ages and as it does, it becomes dimmer and dimmer. Nothing can be done about that.



    The second very common problem on these stoves is that various functions...
    See more | Go to post

    Leave a comment:


  • Re: Fixin computer power supplies as a hobby

    I agree that fixing dead power supplies is fun and definitely a learning experience. Some of those designs are one of a kind even though the general ideas stay the same.

    My thinking on this subject overall is that the designers are not stupid. Sure many times popping in a few new capacitors will get it going. But manufacturers are aware of the figures on MTBF and try to get the supply to the finish line before the whole thing blows up. Sometimes there are actual crummy designs that need to be modified. You want to risk your...
    See more | Go to post

    Leave a comment:


  • Re: Ham/CB/other transmitter radios... linear vs switching PSU?

    Citing the frequencies of some generic switching supply and assuming that broad band interference will be transmitted and create interference with surrounding equipment is just ignorance. There are all kinds of linear and switching supplies. You get what you pay for. A typical output spec for a high quality 12 volt switcher is 150mv of noise at rated output.

    Look at how many of our devices are powered by cord mounted switching supplies and somehow these rarely cause problems with computer peripherals,...
    See more | Go to post

    Leave a comment:


  • Re: Dim Clock LCD on Jenn-Air wall oven

    While replacing caps on the display board used to be a great idea, keep in mind that even with a working display pcb, the VFD displays wear out and dim with age. There is nothing you can do other than to replace the VFD tube itself - it is NOT an LCD. Good luck finding just the VFD...that's when you get to consider replacing the entire assembly.
    See more | Go to post

    Leave a comment:


  • Re: LM317 constant current question

    Commendable
    It is typical to find most technical literature devoted to looking at the world from a voltage perspective. For some reason people have no problem with the idea that the ideal voltage source can deliver an infinite amount of current to maintain a given voltage. But, the idea that an ideal current source can provide an infinite voltage to maintain a constant current is somehow unacceptable.

    As mentioned, the LM317 has an internal band-gap reference of 1.2 volts. That is a special physical thing that is very stable...
    See more | Go to post
    Last edited by Longbow; 04-21-2018, 09:38 AM.

    Leave a comment:


  • Re: Questions about leds in series.

    Of course you can run them in a series string. Prove it to yourself by putting them together on a bread board. I don't know why anyone would ask for trouble in this way, but it CAN be done if the voltage drops on all the individual LED's add up to the applied voltage. Ask the question: using a regulated voltage? Using a regulated current? Xmas tree LED strings are probably an example of just crossing your fingers and hoping for the best.

    Since a typical LED will work over a wide range of currents, you can get away with sloppy designs....
    See more | Go to post

    Leave a comment:


  • Re: Help with LED brake lights

    Key point: unknown manufacturer, item purchased on auction site.
    From personal experience, there is a wide variation in the quality of discreet led's as well as with automotive LED modules. Some work OK, but burn out quickly. Some don't work at all, like yours.

    The point: save a few bucks on the part, but be prepared to waste countless hours of your time trying to reverse engineer your vehicle's electrical system, or figure out why the part you have won't work in your particular vehicle.

    Someone has tried this same thing,...
    See more | Go to post
    Last edited by Longbow; 04-21-2018, 08:39 AM.

    Leave a comment:


  • Re: Help with LED brake lights

    Reading the schematic (with difficulty), refer to page 3-16. #160 appears to be the brake switch, which then connects to a computer unit, #118. The stop light is #639, appearing on page 3-45. If I'm reading things correctly, page 3-45 is a simplified drawing that does not show the computer that controls that stop light. This car has a pretty complex electrical system. It would be helpful to get the English schematic.
    See more | Go to post

    Leave a comment:


  • Re: Help with LED brake lights

    Sorry if I find this very funny. I've never had any problems like this, but it is very interesting. I'd like to know the brand or the web site that provided the LED unit. I've always had good luck with Superbrightleds. You might be surprised at what they can stuff into an LED module that may interfere with your project.

    I think this vehicle has a lamp-out feature. On most vehicles it just illuminates a light on the dash, but some vehicles cut the power to the light. The most critical circuit has always been the directional flashers which...
    See more | Go to post

    Leave a comment:


  • Re: Auto engine management ecu

    We are positively inconvenienced by a question of such generality as yours. If you have a particular vehicle, or a particular fault your are tracing, perhaps there could be some intelligent suggestions.

    An ECU is just a small computer, tailored to monitor a number of sensor inputs and respond accordingly. Do not fix that which is not broken....
    See more | Go to post

    Leave a comment:


  • Re: Oven broiler stuck on!!!!

    The broiler element draws high and constant current. It is likely that the broiler relay needs to be replaced. I imagine that the relay contacts welded themselves together and it will happen again soon. The relays are common and inexpensive. Replace both of them together.
    See more | Go to post

    Leave a comment:


  • Re: Sencor SCD 3554 MR - no backlight

    The open circuit voltage across the faulty LED will not be the same as when that LED gets replaced. Order a few SMD parts of the proper size, and they will most likely work fine. There are already current limiting resistors in the LED circuit I will say 99% certain. This is a typical example of SMD led chips run near the limits, thus increasing heat and shortening the life of the part. Replace all the LED's in the string, not just the one that measures open.
    See more | Go to post

    Leave a comment:


  • Re: Help me identify this little bugger (schotty diode?)

    There are zillions of these BAT54 dual diodes in SMD boards of many types. I will guess that it is simpler to use a package that is identical to most of the other parts, to make it easier for the assembly machines. Seems like most of the schematics I see use plenty of these as steering diodes on VFD display boards or system control boards. Did a new part fix the problem?
    See more | Go to post

    Leave a comment:


  • Re: Netgear R6300v2

    The link to the NVRAM chip tells you which pins do what. These things don't have a unique reset pin, but are reset via serial data commands. Don't worry with the chip, unless you have found that heating/cooling the chip itself reproduces the problem. The thing to check if possible is the main micro. If that thing is a BGA then forget it unless you have a schematic. Locate the various regulators on the board and check the voltages. A failing filter on these regulated lines can cause erratic power up behavior, you can be sure. But that doesn't mean it HAS to be...
    See more | Go to post
    Last edited by Longbow; 01-20-2018, 12:52 PM.

    Leave a comment:


  • Re: Pioneer XR-A670 cd changer mechanical issue

    Replace the rubber mounts as suggested. Spraying them won't do anything.
    See more | Go to post

    Leave a comment:


  • Re: Sony mds JA 30 ES minidisc

    Since the symptom can be reproduced, just get out your heat gun and find out what part of the unit is sensitive to heat. Or wait for failure and selectively freeze various things. Better than guessing at least for now. Usually mechanical things work better when they are warm, so I would suspect electronics first....
    See more | Go to post

    Leave a comment:


  • Re: Overvoltage protection design ideas

    There IS an ideal solution to your problem, as described. A box of units cobbled together is not going to require high level engineering for you to get into operation. In fact, at this point you don't even know if your unit will function as expected over a long haul. You have a very common requirement for inrush protection. In this case you are not too worried about overloading the mains, but simply providing a soft start situation for your equipment. Thermistors are used industry-wide on all types of equipment and I recommend that solution...
    See more | Go to post

    Leave a comment:


  • Re: Marantz Tuner issues

    Unlikely that you would have power supply hum on one higher station but none on any lower stations. Does your unit have the hum problem with a simple FM dipole? I'd say the next troubleshooting step is to short the receiver antenna terminals and see if there is any hum when tuned to your upper station. Compare with lower end of the band. In other words, check for RF interference combined with a weak signal strength. Does orientation of the receiver change the symptom? Try to narrow it down to signal strength, mono/stereo modes, possible interference from...
    See more | Go to post

    Leave a comment:


  • Re: Scr / thyristers

    That particular spec means that the device has to withstand at least 200v. reverse. But there are other important specs with thyristors, especially the turn-on voltage and turn-on pulse width required. Also, you need to look at requirements for the reverse voltage width. If too narrow, the SCR won't turn off. Or, you could just slap in the replacement and look for smoke (just kidding).
    See more | Go to post

    Leave a comment:

No activity results to display
Show More
Working...
X