Any electronics gurus here? Stereo receiver issue...

fast14riot

fast14riot

Joined
Oct 27, 2010
Messages
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I have an old Pioneer SX1300 receiver that is having issues.

First off, this is at my work and is used for FM only and is hooked up only to one speaker currently.

Issue #1, station memory isn't working over night any more. I know there is a CR2340 in there just for this, but it is soldered to the board, can I feasably switch this to a cheaper and easier to find CR2032 button cell? A battery holder is a buck and would be much easier to deal with.

#2, would the aforementioned dead cell cause the volume to raise and lower sporadically? It will be playing fine and all of a sudden it will spike up a noticeable amount. No RF interferrance or noise, just output volume.

It is clean and dust free inside, I cleaned it (dry paint brush and vaccuum wand) and there is plenty of airspace around it too. All component hook ups work fine and all buttons were cleaned and are making good connection.


Hope someone has a little bit of experiance with this and can help!


-Xander
 
#1 - the 2032 has a different mAh, it *should* still work, but not for as long.

#2 - no, that sounds like a different issue. Could be a bad capacitor in the output path, could be something else. I'm going to dig through the service manual and see if anything leaps out at me.
 
Thanx, I figured the 2032 cell would be fine, as this receiver is turned on all day every day and it really needs to maintain memory overnight.

I've been going over the service manual as well, but I have a very limited knowledge in this stuff. I'm used to more of an amp circuit or pre-amp and either buzzing or cutting out, but never dealt with these volume issues.


-Xander
 
If you don't see any capacitors that are in obviously bad shape (split, dried out crusties, etc.) the most likely next culprit is the volume pot. Check connections to it, and either try cleaning the contacts and if possible, resistor pad, or replace.

It is VR402 on the circuit - part number ACT1040 (though I think any 100k stereo pot should work)
http://parts.pioneerelectronics.com/part.asp?productNum=ACT1040


- note -

it shouldn't make any difference, but it might be worth while to run a second speaker on it for a bit - just to make sure the amp isn't bridging with the uneven load. I doubt it, but eliminating one more possible variable before cracking the circuits open is always welcome in my house...
 
The volume issue sounds like a Potentiometer problem. They oxidize over time. As noted, you may want to try a second speaker as well for a balanced load on the amplifier section.

Regarding the battery, why not just solder another lithium to it? Once every ~10 years is pretty low maintenance. A small battery is really more trouble then it is worth IMHO. If you are going to change the battery type, pick something with more reserve capacity.
 
Thanx guys! I didn't see any caps that looked bad, I will take a closer look once I get a new battery.

I will also check the volume pot and clean it. There is a second speaker, but I do have to run wiring to it across the store. I have a spool of old solid 16-2 Bell phone wire that should make excellent speaker cable.

Once I get in there I will report back, but until then, if anyone has any other ideas feel free to pst them here.


-Xander
 
So I ran a second speaker this morning and so far haven't had any volume spikes. Its been running a couple hous now, and before it was every few minutes it would spike for a couple seconds. Looks like it was bridging with the uneven load.

Still haven't picked up a lithium cell yet. Its not a huge deal, just kind of annoying to have to find the station every morning.


Thanx for the tips guys!


-Xander
 
Will do. Funny, this receiver was kinda an impulse buy. My uncle is planning on moving out of state and being the anally retentive person he is, has decided to unload everything deemed "unnecesary", so I scored th receiver, twin tape deck, 12" 3 way speakers, and a sony 5 disc changer for $40. All I wanted was the speakers, since everything was Pioneer and all the same vintage as he bought all this stuff new at the same time in '83 (except the cd changer, that's 10 years newer) and has taken extremely good care of it since! See above character reference for details...lol!

I currently run a Pioneer receiver from the 60's and its still going strong, so I took this one to the store. Going good now!


-Xander
 
Hmmm, seems the changing output is back. Not near as bad as before, but it back. I will clean the volume pot on Thursday and hopefully that will take care of that issue.


-Xander
 
Try cleaning the other switches on the receiver too. Tape Monitor switches were notorious for messing with the audio path. Just spray with tuner shower/cleaner in any gaps or openings in the switches and work the switch several times.
 
That's the plan, I have a can of it already. Will see what's going on with it tomorrow when I get back to work.


-Xander
 
That's the plan, I have a can of it already. Will see what's going on with it tomorrow when I get back to work.


-Xander
 
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