Subject: Re: DX440 mod - how to

From: [email-masked] (H}kan Lennest}l)
Date: 5 Dec 91 16:25:51 GMT

[email-masked] ([email-masked]) writes:
: In article <[email-masked]> [email-masked] (Graham Oberem) writes:
: >The following mod will remove the "chuffing" heard while tuning the
: >Sangean 803/DX440 radios.
: >5.	Locate the 8-wire flat cable which runs from the circuit board above
: 
: >6.	Identify the second wire
: >	from your left in the cable.  
: >	Bend this wire up and out of the way
: 
: >9.	Turn on the radio and enjoy the lack of "chuffing". 
: 
: This is amazing.  If all the second wire does is cause chuffing,
: why is it included in the design in the first place?  Does anyone 
: have any insight into what this particular connection is SUPPOSED
: to do?
: 
: Thanks for the info, Graham.
: I'll probably do this when my warranty runs out, but it's odd that this
: modification apparently has no negative effects.
: -- 
: Perry G. Ramsey         Department of Earth and Atmospheric Sciences
: [email-masked]  Purdue University, West Lafayette, IN USA
: perryr@purccvm          This signature gives you specific legal rights.  You
: N9LFF                   might have other rights that vary from state to state.

The main purpose of the muting circuit that gets disconnected by this modification is
probably to make the set silent when you hit the "search" button. I personally think
that it is a feature to hear the "search" in operation. 

The reason why the set is "chuffing" is a result of a bad desing of the
mute circuit:
   It is placed where there is a DC potential.
   It is placed after the volume control (less audiable if placed before).

  o
/Hakan
-- 
--------------------------------------------------------------------------------
 E-mail: [email-masked]       | Hakan Lennestal, Telia Research AB
 Fax:    +46-920-75490                  | Aurorum 6
 Voice:  +46-920-75459                  | S-95175 LULEA