Super Hang-on: audio problem

baritonomarc

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Hi all,

my Super Hang-on has an audio problem. All the sounds, musics, effects are ok (i made a test on those), but only the right speaker works. To see if the left speaker was broken, i opened the back cover, connected the cables going to the working speaker to the non-working one, and i had sound... so the left speaker itself works and the problem must lie on the source (amplifier? PCB?). How can i test if the PCB is outputting the audio signal ? Consider that i am experiencing some problem identifing the pinout of the PCB (yes, i have the manual with schematics, but those "signs" are like Cinese to me... i need a "decripted" pinout). If the problem lies on the sound amplifier, what shoud i ceck first?

Thanks :)
 
OK, a reply for the Klovers that will be forced to face this problem in the future ;)

I disconnected the sound amplification board:

sam0551slim.jpg


I followed the traces from the faulty speaker PIN checking all the soldering and fast i noticed this:

sam0547slim.jpg


... a toasted transistor!

Let see this on the solder side:

sam0548slim.jpg


I will buy that transistor next week (and all the caps of the PCB) and will report the results :)
 
Ok, all the caps and the toasted transistor have been substituted. The channel that was working is still working (so the re-capping was succesfull), but i have a "Hum" sound coming from the speaker that had the transistor substituted.

The other speaker works perfectly (no humming at all), so i suspect that the new transistor (TDA2030A, not TDA2030) is not 100% compatible with this board... anyone had a similar problem here?
 
going on a limb, based on another user looking for a transistor for something last week or so.... the letter designations I THINK are only for like max voltage tolerance.

run a cross reference on both #'s on http://www.nteinc.com/ and see if they come up with the same replacement part.
 
Thanks for the reference! They report the same NTE transistor for all the TDA2030xx family... excluding the ground problem, considering that all the caps have been replaced and that one speaker works well, i really don't know where that hum noise comes from... any other idea? :)
 
The transistor you subsituted is fine, seems to me that another component on the board wants replacing. Have you checked your diodes?

I have two Super Hang-Ons that want restoring.
 
Check all the components between pin 4 (the pin that had the burnt trace) and the pin where the speaker wire connects to the board.

You have a short somewhere. It's either on that board or it's in the wiring harness.

RJ
 
Thanks for suggestions, i will check all the components on that track.

I wanna add an info, just to see if it's commonly reconducible to a specific component (diode or resistance or cap or whatever): when i turn completely off the volume pot, the hum increases a lot; When i start turning the pot to give some volume, the hum reduces to a certain level (but is always there)
 
Is the heatsink getting hot on the replaced chip?

If it's being overloaded you could get that hum. Check those components on the output. Something had to short to blow that chip and that could still be causing the hum.
 
I noticed that unplugging the audio signal from the main PCB, the hum is still there, so the interference doesnt come from the main board. This should exonerate the wiring harness from being the cause of the problem, isnt it?

I gave a check to all the components: resistors are ok (the resistance is correct), diodes with orange edge are ok (shorts only in one direction, as expected). Black diodes with grey edges are, instead, misterious to me: they have approx 520 ohm on one direction, approx 1200 ohm on the other direction... is this normal?
 
diodes should read open one way, soooooooooooo...... you may have found your problem. it's got juice flowing a way that it shouldn't be. :)
 
Ok, all the caps and the toasted transistor have been substituted. The channel that was working is still working (so the re-capping was succesfull), but i have a "Hum" sound coming from the speaker that had the transistor substituted.

The other speaker works perfectly (no humming at all), so i suspect that the new transistor (TDA2030A, not TDA2030) is not 100% compatible with this board... anyone had a similar problem here?

For future reference:
The TDA2030 is not a transistor but is actually an integrated circuit -- an audio amplifier.
The "A" within the part number is the die revision. The later parts (TDA2030A) can pump out a little more power than the original TDA2030's (18W versus 14W). The TDA2030's are no longer made but the TDA2030A's are.

The new part number to replace this one is TDA2030AV.
"V" means leads are formed for vertical mount. You do NOT want the TDA2030AH. The "H" suffix means the leads are formed for horizontal mount... you would need to rebend all the leads.

Ed
 
Sorry for upping this, but i solved the HUM problem and i wanna share for future reference: diodes where good out of the circuit (note to self: diodes testing bad into the circuit could be good). My audio amply board was not an original super hang on amply board, but an atari Audio 2 regulator coming from a 720... WTF!

With the correct wiring in my hands i succesfully found out that that that PCB has a couple of 12V voltage inputs, one for each channel. Even if it's still a mystery to me how both the channels were working with only one line juiced (even if with the annoying HUM), a matter of fact is that having that line up and running solved 100% the humming

another machine is 100% up and running then!!!
 
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