[ Fixed !] low sound on my 800XL (ntsc)

[+StaxX28]

Hi all,

on my 800XL (ntsc) the sound as really low level...

same problem on the RF switch cable and the monitor connector !

 

"Pokey" problem ?

800XL PCB faulty ?

 

My DIN 5 pin--> Scart cable is like this...

That's good ?

 

Thanks

 

ps: sorry for my English

Edited May 30, 2008 by StaxX28

[bluemax2007]

With UHF ?

[+StaxX28]

Same problem !

[Clint Thompson]

TV speaker?!?!

[+StaxX28]

It's not a problem of TV speaker... All of my other atari XL (PAL & SECAM) works perfectly on my TV, only the 800XL NTSC has sound at really low level !

My TV is a multi standard (PAL, NTSC and SECAM)

 

I also tried the TV-OUT NTSC of my GP2X on it ... no problem with sound !

Edited May 27, 2008 by StaxX28

[classics]

Try swapping out the LM358 opamp.

 

Steve

Edited May 27, 2008 by classics

[+StaxX28]

Ok, I'll try this.

Thanks !

[+StaxX28]

I don't find the LM358 !

The only thing that look similar to the LM358 I found is here (U1)...

 

The RCA 323 (CA358E ?) is like the LM 358 ?

Edited May 27, 2008 by StaxX28

[+StaxX28]

It's ok !

An electronics engineer gave information to me... the CA358E is similar to the LM 358 !

I bought a LM358N on ebay, wait and see...

[+StaxX28]

I received the LM358N today...

I put it instead of the CA358E and now my NTSC 800XL works perfectly!!

Thank you so much Steve for your help !

[mellis]

Try swapping out the LM358 opamp.

 

Steve

 

Sorry to resurrect an old thread, but I suspect I am having a similar issue.

 

I recently fired up my 800XL for the first time in a good while, and just to make sure things were OK, I ran the self test.

 

The problem I am seeing is that I get absolutely no audio from the "Audio/Visuals" test. When it attempts to play the notes, I hear nothing until voice 4. Then I hear "pop - pop - pop - pop pop pop" instead of musical notes. What's interesting is that the voice that plays the pops varies. If I power off the machine and then try again, Voice #3 might pop instead of Voice #4.

 

Another point of interest: when I power up the 800XL, I do hear the normal "buuuuuuuuurrrrrrrp" sound it makes while it looks for a boot device (I have none connected for these tests). Also, the keyboard click works just fine.

 

I tried reseating those chips that were socketed. It looks like most of the custom ICs on mine are, but the RAM isn't and neither is the LM358, unfortunately (I can desolder it though).

 

Do you suppose my 800XL might need the opamp replaced too?

 

Thanks for any advice!

[thorfdbg]

Sorry to resurrect an old thread, but I suspect I am having a similar issue.

 

I recently fired up my 800XL for the first time in a good while, and just to make sure things were OK, I ran the self test.

 

The problem I am seeing is that I get absolutely no audio from the "Audio/Visuals" test. When it attempts to play the notes, I hear nothing until voice 4. Then I hear "pop - pop - pop - pop pop pop" instead of musical notes. What's interesting is that the voice that plays the pops varies. If I power off the machine and then try again, Voice #3 might pop instead of Voice #4.

 

Another point of interest: when I power up the 800XL, I do hear the normal "buuuuuuuuurrrrrrrp" sound it makes while it looks for a boot device (I have none connected for these tests). Also, the keyboard click works just fine.

 

I tried reseating those chips that were socketed. It looks like most of the custom ICs on mine are, but the RAM isn't and neither is the LM358, unfortunately (I can desolder it though).

 

Do you suppose my 800XL might need the opamp replaced too?

Likely not. All audio output goes through this OpAMP, and if you can hear some voices, then this path is fine. Can you load from disk, i.e. is the serial transfer working?

 

Audio voices are already mixed within POKEY, which means that if you hear some, but not all of them, something's wrong either with POKEY, or with its addressing. I would check for a POKEY replacement - is it socketed on your machine?

 

So long, Thomas

[mellis]

Likely not. All audio output goes through this OpAMP, and if you can hear some voices, then this path is fine. Can you load from disk, i.e. is the serial transfer working?

 

Audio voices are already mixed within POKEY, which means that if you hear some, but not all of them, something's wrong either with POKEY, or with its addressing. I would check for a POKEY replacement - is it socketed on your machine?

 

So long, Thomas

 

Thanks for your thoughts, Thomas.

 

I think there are three useful clues here:

1) I can hear the disk I/O beeps.

2) I cannot hear any other audio with the exception of a very slight popping sound on one of the four voices.

3) The only time I can hear high pitched sounds is when the disk I/O beeps play.

 

Because Voices 1-4 are, for all intents and purposes, not audible, I thought this problem sounded more like the OP's issue than a bad POKEY. What's more, my opamp is the same variant as the OP had in his machine (it's a CMxxx not an LMxxx).

 

I could be mistaken about this (as I've not scrutinized a schematic), but I thought I remembered hearing that the keyboard-speaker sounds where handled by POKEY, but that a different circuit was responsible for sending the audio out, and therefore, that particular opamp was not involved. As far as that goes, maybe I'm confusing my 800XL with the 400/800 machines that had an internal speaker.

 

Thanks again...

 

EDIT: There were three useful clues, not just two.

Edited April 19, 2009 by mellis

[ivop]

The keyboard speaker sound is generated by GTIA (S3 output pin). It's mixed with the Pokey sound by the same LM358 opamp, so, as thorfdbg says, this path is fine.

[emkay]

A courious thing this ...

 

All in the Atari is "US" standard. Only the Audio is correct to the "Deutsche Industrie Norm"

 

The voltage there is about 0,8 Volts, while SCART/ Cinch etc. use the peak of 1V signals.

[mellis]

Likely not. All audio output goes through this OpAMP, and if you can hear some voices, then this path is fine. Can you load from disk, i.e. is the serial transfer working?

 

Audio voices are already mixed within POKEY, which means that if you hear some, but not all of them, something's wrong either with POKEY, or with its addressing. I would check for a POKEY replacement - is it socketed on your machine?

 

So long, Thomas

 

Well, Thomas - you are the man. It was the POKEY chip just as you suspected.

 

Today I swapped the 800XL's POKEY with a POKEY I pulled from my secondary 5200. Once that was done, I fired up the self-test, and all voices are working flawlessly.

 

Thanks for Thomas and ivo for helping me out with this!