Re: Tube Sreamer probs

On 31 Jan 2006 12:00:15 -0800, bkahle@xxxxxxxxxxx wrote:

>
>Grip wrote:
>> TS10 classic, my vintage one was stolen years ago, this is the replacement.
>> Problem is I hit it with the wrong adapter (multi voltage, think I had it on
>> 12)and it no longer works. It is not worth taking to a tech, and I have a
>> little<-------- experience as I've done some mod kits, like I said very
>> little. What might be the most likely component to be fried, although
>> nothing actually looks fried, I might swap first? I know this is shooting in
>> the dark, but hey, I could replace the whole pedal for what a repair would
>> cost.....thanks guys!
>
>Do you own a meter, preferably
>one with a diode test function?
>An ohm meter would work as well.
>
>As a protective measure, most well made pedals
>that allow for an external power supply have a small
>signal diode placed across the supply rail in reverse
>polarity. This component is usually a 1N914/1N4148-
>type. (Orange glass body. Cathode=black band)
>
>It should be located on the board in close proximity
>to the ext. power jack. If it measures as a short, it
>did its job and saved the rest of the s/s components
>in the pedal. Keep in mind that it protects the circuit
>mainly from applied reverse polarity as well as in some
>cases, applied ac. It however does not protect from
>applied over voltages which can "get through" and
>lead to more serious failures.
>
>If you do find this part to be the issue, it is an easy fix.
>The part can be purchased almost anywhere,
>including Radio Shack, etc. Be sure to put the
>new one back into the board properly orientated.
>
>Of course you could have caused other issues,
>but this is the first thing I'd check.
>
>Report back & let us know how you did.
>
>bk

I'll have to 2nd Bill's post. Unfortunately I've also seen
manufactures use rectifier diodes (black body with white band) which
handles too much current, instead of small signal diodes in this
protection method and it ends up torching the board. 

As Bill indicates, a protection diode is usually very close to the
power connector.
.

Relevant Pages

  • Re: WRT54G fried - plugged AC into a DC device. Doh. Any suggestions?
    ... There's a protection diode on the v1.0 and v1.1 ... of the SOT regulator package near the power connector. ... diode, which usually indicates it has exploded inside. ... the other has a wide range regulator similar to the v2.0 and above. ...
    (alt.internet.wireless)
  • Re: How to PostMortem?
    ... > well they perform for each type of surge. ... "American Power Conversion's Equipment Protection Policy: ... one uses a #12 guage wire less than 5 ...
    (comp.os.linux.setup)
  • Re: Surge Protection?
    ... I lost you with the knot thing. ... I'm planning on whole house protection here and wasn't happy with the water ... > Idea that power turns on like water flowing down a channel ... > for the AVR to provide effective lightning protection. ...
    (alt.security.alarms)
  • Re: ups installation question
    ... They protect connected devices from sudden power ... UPS AKA battery back-up: ... Most have surge protection et al, ... The issue of UPS vs. auto battery life is more a limitation of the ...
    (alt.sys.pc-clone.dell)
  • Re: measuring output of adapter
    ... Designers often forget that with continuous ratings up to 75 volts and ... they can be used as convenient small power devices. ... lumps of silicon and simple protection devices. ...
    (uk.comp.sys.mac)