NTSC Atari 400 - no sound?

[KubaCZ]

Hi, I've got another problem - I have NTSC 400, which doesn't output sound. I think it's NTSC one, because peeking 53628 returns 15 - so it's maybe because my TV can't get sound from NTSC machine? Diskette drive seems to work (stopped booting to MyDOS - don't have enough ram/not XL os, but worked). Any ideas?

 

Edit: I'm getting noise from TV, I've tried different cables so it's not because it's broken - picture is clear.

 

Oh and my TV is PAL, but if I remember correctly it works with NTSC too.(Sony triniton from 90's)

Edited November 3, 2011 by KubaCZ

[Fox-1 / mnx]

Oh and my TV is PAL, but if I remember correctly it works with NTSC too.(Sony triniton from 90's)

 

NTSC compatibility on PAL TV using RF input is really rare so I doubt this Sony can do it.

 

It may however support NTSC using the composite/S-video inputs (which isn't of much use with a stock 400).

[Rybags]

Even foreign gear among PAL countries can have that problem.

 

It all depends on what frequency seperation is between the RF video and audio parts.

 

The RF modulator would need to be modified - it would probably be just a lot easier and give a better result doing the mod to add monitor port.

[KubaCZ]

Hmm, I was thinking that - I wanted to keep my 400 original, but it looks that this mod is really needed.

 

I've found this schematic, will it work?

 

Btw: is 400 usable for older games booted from floppy/casette, if it has only 16k of ram?

[mimo]

Cassettes no problem obviously game limit us 16k. Pretty much no on loading discs, especially with dos.

[mimo]

That video mod looks interesting, can anyone translate the text?

[Rybags]

You could just type it into Google's translate page.

 

That mod only provides composite, ideally you'd want one that also gives colour + luma.

 

Given it's a 16K machine only, you'd be way better off just asking someone if they want to swap a 64K XL for it.

[KubaCZ]

I actually have 320kB XL,130XE, 2x 800XE and stock 800XL, so that's not problem

 

 

I don't understand Polish language very well, but here's my translation:

 

1. make hole in case, where you'll put DIN5 connector

2. on main PCB, find connections R161 or(and?) C164 (right to the POKEY)

3. to connections R161/C164 put resistor R6 and connect it to rest of the schematics

 

I wanted to have 400 in my collection, but also working with sound and ability to play some games/programs