• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

SX 828 tuner board AWE-016

P

pa_200

Well-Known Member
When trying to lift the little MPX board I touched with one finger the trim pot VR2 on the tuner board AWE-016 and was surprised, that the VR2 could be turn without any resistance. Bad enough I didn’t remember the position or value it was set before.

What is the purpose of this trimmer and what values to I have recheck or to adjust?

There is a high possibility that the trimmer is broken inside, but I would like to wait for some advice from you before I go on.

Can anyone help?
 
Register to hide this ad
VR2 is part of the MULTIPLEX STEREO Circuit used to adjust level of separation between L&R in Stereo. To get it back in alignment You'll need a multiplex generator and the specialized knowhow to use one(in addition to using an O-Scope, Sig-Gen, and frequency meter/generator). For right now, leave it. But if you don't have the gear to align it, take it to a shop that does RF/IF/Multiplex alignments.

This is from the 828's Service manual and is included as an illustration to the function of VR2.

upload_2019-5-13_8-35-30.png
 
With that problem in front, does it still make sense to change the caps or shall I leave that board as it is?
 
is there anyone around where you can get an alignment? if so and you are confident it can be repaired i see no reason why not. is that vr adjustment cap sort of loose and floating? a check with a meter will or should tell you.does the fm play well and have separation with a stereo "on" lite now? if that vr is mechanically damaged and is still holding its adjustment and everything works you could leave it as it is.or not knowing how sensitive it is you could replace it with a bournes item set at the same resistance as the old vr. i guess it all just revolves on the ability to get it aligned and a set that old will need it.that said its cheaper to change any parts yourself.sx 828 fm boards come up on ebay from time to time,but they arent exactly plentiful and may not be any better than the one you have. ecaps replacement does make a difference use stacked films.
 
You must log in or register to reply here.
Back
Top Bottom