Tweakers' Asylum

RE: MJ 15024 / MJ 15025

74.245.249.246

wheezer

In Reply to: RE: MJ 15024 / MJ 15025 posted by wlee on November 01, 2008 at 20:06:10

William Hi,

I suggest first getting the Service Manual and bias the amp to spec. Check the V across each ER and their heat.
Replace all the emitter resistors and use mills. Recheck their voltages.
Rebias and listen to it; if the problem persists, change all the bi-polars with matched. It may be worth it to purchase a hand held transistors tester and match them yourself.
Let me know how you proceed.

Mitch

Follow Ups:

uA ? - djk 16:38:40 11/02/08 (3)
Most handheld transistor checkers only run a few �A of current, do you really think that is useful in matching 16A transistors?
- RE: uA ? - wheezer 17:52:20 11/02/08 (2)
  Matching the hFE should be good enough.
  - RE: uA ? - djk 01:04:43 11/04/08 (1)
    At what current?
    
    I must not be expressing myself clearly.
    
    They need to be matched at the operating current, which are way beyond those little hand held testers.
    - RE: uA ? - wheezer 15:17:23 11/04/08 (0)
      It's been a while but I recall measuring the hFE with whatever the meter put out. They'll drift within a few days of operation anyway.
      Also read something similar in Morgan J's book.
      Why, what's your take?

Post a Followup:

FAQ

Post a Message!

Forgot Password?

Moniker (Username):
Password (Optional):
	Remember my Moniker & Password (What's this?) Eat Me
E-Mail (Optional):
Subject:

Message:	(Posts are subject to Content Rules)

Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:	Automagically notify you when someone responds.

To view your new posting or follow-up, click on the RELOAD or REFRESH button on your browser.

This post is made possible by the generous support of people like you and our sponsors:

McShane Design