7 replies to this topic

[Atari-Jess]

My POKEY is VERY quiet, but the GTIA sounds are not.

I can tap the keyboard "BEEP BEEP BEEP"

but I play anything that uses POKEY, (even in BASIC) and its (.... .... ....) so I turn it up and its (,,,, ,,,, ,,,,)

If I turn it ALL THE WAY UP its (beep beep beep)

I opened my 130XE up and checked for broken spots, nothing seems off...

Any suggestions?


(I don't know how recent a problem this is, I only just started using my 130XE)

Edited by Atari-Jess, Sun Mar 26, 2006 8:26 AM.

[warerat]

Atari-Jess, on Sun Mar 26, 2006 2:24 PM, said:

My POKEY is VERY quiet, but the GTIA sounds are not.

I can tap the keyboard "BEEP BEEP BEEP"

but I play anything that uses POKEY, (even in BASIC) and its (.... .... ....) so I turn it up and its (,,,, ,,,, ,,,,)

If I turn it ALL THE WAY UP its (beep beep beep)

I opened my 130XE up and checked for broken spots, nothing seems off...

Any suggestions?


(I don't know how recent a problem this is, I only just started using my 130XE)

Are you saying you can barely hear POKEY sounds, or not at all? Are you using the RF mod output or direct from the A/V port? When you say "turn it up", do you mean your volume on your display or the software controlled volume?

Could be several things.

1) Check to make sure you have +5V on POKEY pin 17. There are individually filtered +5V supplies on the 130XE.
2) Bad op-amp at U1. Labeled LM358 or 1458. Look for bad joints around here. Mixed output comes from pin 1, POKEY input at pin 6, and GTIA input at pin 2. In a pinch, short pin 2 to 6 to see if any audio comes out. If you hear the POKEY, check connections at R1-R4, and C17.
3) Bad POKEY

If you get no audio from the RF output, but you do at the monitor jack, then either your RF mod is bad or there's a bad connection.

Good luck!

[MEtalGuy66]

Are you using the RF modulator, or the DIN monitor connector for your audio output?

[Atari-Jess]

RF modulator. And yes, the POKEY is just much quieter than the GTIA sounds even when the volume is turned to maximum.

IT IS THERE, just very faint. I will investigate the listed suggestions and report back with my results.

[Atari-Jess]

I get 4.38v from my multimeter at pin 17 from POKEY

the joints around the LM358 look fine

I've tested the monitor plug audio output, and its a quiet (not silent) POKEY, which is the same.

Upon closer inspection I am seeing a resistor that appears broken at C304
the wire is broken and somewhat bent back a little.

(but reading into it I found out it was for the US doubler mod I have on of my 1050s from the previous owner, so scratch that)

...Im not sure where the connections at R1-R4, and C17 are.

and I'm not sure how exactly you want me to short the pins on the op amp

Edited by Atari-Jess, Mon Mar 27, 2006 3:30 AM.

[Atari-Jess]

I guessed what you meant about pin 2 and 6, and when touching them together the POKEY comes in loudly, but somewhat dirty sounding.

Edited by Atari-Jess, Mon Mar 27, 2006 3:36 AM.

[warerat]

Atari-Jess, on Mon Mar 27, 2006 8:37 AM, said:

I get 4.38v from my multimeter at pin 17 from POKEY

the joints around the LM358 look fine

I've tested the monitor plug audio output, and its a quiet (not silent) POKEY, which is the same.

Upon closer inspection I am seeing a resistor that appears broken at C304
the wire is broken and somewhat bent back a little.

(but reading into it I found out it was for the US doubler mod I have on of my 1050s from the previous owner, so scratch that)

...Im not sure where the connections at R1-R4, and C17 are.

and I'm not sure how exactly you want me to short the pins on the op amp

4.38V is pretty low. Check a +5V somewhere else, like pin 16 on the 'LS138 above it. If it looks good, run a temporary jumper from pin 16 on the 'LS138 to pin 17 on the POKEY. If it fixes it the problem, you probably have some leaky electrolytics in the DC filter where the power connector is or your power adapter might be flaky.

[Atari-Jess]

warerat, on Mon Mar 27, 2006 10:57 AM, said:

4.38V is pretty low. Check a +5V somewhere else, like pin 16 on the 'LS138 above it.

edit: I recalibrated my multimeter automatically, and afterwards the POKEY shows 4.95v, the LS138 shows 4.40

Edited by Atari-Jess, Mon Mar 27, 2006 10:32 AM.