Paperboy Speaker Hum

Superully

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the left speaker on my paperboy is producing a loud annyoing hum. i can hear the game sounds, but the "hum level" is too high to be acceptable. i've switched wires between the two speakers to rule out a broken speaker, but then the hum moves from left to right. also tried a new speaker on both speaker connectors: loud hum on the left, faint hum on the right speaker.

your turn ;)
 
thx, but where do i have to start looking? those system 2 boards are g-i-g-a-n-t-i-c!!!

No problem, send me a plane ticket to Germany and we will both look at it together. :)

You can check the audio from the board but you will need a amplifier of some kind or you can use a ear piece with a crystal just to see if there is intelligent audio there.

The caps I was talking about will be at/near the audio amp.
 
No problem, send me a plane ticket to Germany and we will both look at it together. :)

just posted ;)


Luckily the amplifier is not on the System 2 main boards. Try the ARII board assuming you are still using it.

The caps I was talking about will be at/near the audio amp.

if i show you a picture of the ARII board, can you point me in the right direction?

EDIT: just checked, have an ARIII installed ->

6589729045_30b23bd618_b_d.jpg
 
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just posted ;)




if i show you a picture of the ARII board, can you point me in the right direction?

sure can, when you go to take the pic look closely at the round (electrolytic) caps. Many times they get pushed to one side or the other then a leg breaks off and you can't see it when cap. gets pushed back straight.
 
Looks like your problem is at or near r20 or r29. That sucker got very hot to discolor the connections like that. I also notice some discoloring on the heat sink above the top transistor and that usually means that thing got hot also. They both need to be looked at and tested.

I am looking for a schematic for that board arIII and after I find one I can be more helpful

here is some more reading about the sound on these boards. I hope it helps

http://www.gamesforum.ca/archive/index.php/t-158089.html
 
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Looks like your problem is at or near r20 or r29. That sucker got very hot to discolor the connections like that. I also notice some discoloring on the heat sink above the top transistor and that usually means that thing got hot also. They both need to be looked at and tested.

man, now that you mention it ... i've never realized that before. definitely worth checking out!

I am looking for a schematic for that board arIII and after I find one I can be more helpful

thx a lot for your help, i really appreciate the time you spend on this. hopefully we can work it out.
 
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don't know if it helps, but a ariii pcb assembly layout can be found here and a schematic diagram of the ariii pcb is shown in the system one manual right here!

ok c13 and c15 are right at the output of the audio amplifier so if you can hook up a test speaker at the caps there and see if the humm is there. It will be there on the problem output. The problem can be at the input so let me know witch is the problem c13 or c15. One will have the humm.

Also look at c1 and c5 for any damage or bulging casing and one last thing, have you tried the self test?
 
ok c13 and c15 are right at the output of the audio amplifier so if you can hook up a test speaker at the caps there and see if the humm is there. It will be there on the problem output. The problem can be at the input so let me know witch is the problem c13 or c15. One will have the humm.

alright, so we're talking about the two big capacitors here!

question: where / how do i hook up a test speaker on the capacitor? one lead on the left leg, the other lead on the right one? can i touch the capacitor's legs with the game powered on or do i first have to hook up the speaker to the legs, power on the game, listen for a hum, turn it off again, remove the speaker and check the other capacitor?

Also look at c1 and c5 for any damage or bulging casing and one last thing, have you tried the self test?

will check c1 and c5 as well.

self test comes up without an error!!!
 
alright, so we're talking about the two big capacitors here!

question: where / how do i hook up a test speaker on the capacitor? one lead on the left leg, the other lead on the right one? can i touch the capacitor's legs with the game powered on or do i first have to hook up the speaker to the legs, power on the game, listen for a hum, turn it off again, remove the speaker and check the other capacitor?



will check c1 and c5 as well.

self test comes up without an error!!!

just hook up an external speaker of some type and plant one side to ground someplace and probe with the other side to the cap.

You do this while it is on and you want to probe the +side of the cap. one of them caps will have the noise and that is where the problem is at or near. Like a river just follow it in the direction of the problem, upstream.
 
You do this while it is on and you want to probe the +side of the cap. one of them caps will have the noise and that is where the problem is at or near. Like a river just follow it in the direction of the problem, upstream.

will do as adviced and report back with the results!

btw, must be pretty late "over there" already ...
 
just hook up an external speaker of some type and plant one side to ground someplace and probe with the other side to the cap.

test completed! here are the results of the german jury: ;)

i do have a hum at both capacitors, BUT the hum at C15 is at least double as loud as the hum at C13 (which is more like the hum a power transformer puts out, so nothing spectacular). C15 however is "pretty hummy" ;)

what to do? simply replace the cap? should i replace C13 as well? and if i do, should i also replace the other three caps on the right side of the ariii because they are identical (they are all 35v 3300uF).
 
I would make sure the hum is not at the input before I replace them. You might want to check the + of c1 and c5 to see what you get first. If the hum is not at the input and is at the output then yes replace the cap. I will look over the diagrams a bit better and may print out as my memory is getting bad.

test completed! here are the results of the german jury: ;)

i do have a hum at both capacitors, BUT the hum at C15 is at least double as loud as the hum at C13 (which is more like the hum a power transformer puts out, so nothing spectacular). C15 however is "pretty hummy" ;)

what to do? simply replace the cap? should i replace C13 as well? and if i do, should i also replace the other three caps on the right side of the ariii because they are identical (they are all 35v 3300uF).
 
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