Jump to content

TheDash's Photo

TheDash

Member Since 21 Sep 2017
OFFLINE Last Active Apr 11 2018 12:16 AM

Posts I've Made

In Topic: Atari 400 - no sign of life - black screen

Sun Apr 1, 2018 1:00 AM

It made very little difference sadly. I replaced the Astec modulator with a newer one, just as an experiment, and there was a slight improvement - but I think I'll go the composite mod at some point in the future if I'm going to keep using it.


In Topic: Atari 400 - no sign of life - black screen

Sat Mar 31, 2018 10:09 PM

Well holy Donkey Kong - it works! That was really quite a nerve wracking experience, putting the connectors back together. Yeah, I know it's old, but - so fragile? Well phew anyway.

 

Thanks a whole stack for your help there Dragonstomper - really appreciate it.

 

So I'm not sure what fixed it exactly - but I cleaned the contacts (95% alcohol), pressed down on the chips a little (one of which clicked), and that was it really. Now to reassemble the thing properly. More nerve wracking coming up.

 

I can't tell you much about that RAM board - it would have been done back when I was more interested in playing with Star Wars toys and reading comics, and getting to school on time. But I'll bet it wasn't cheap for sure.

 

The picture is snowy as expected - but pretty badly so. Was it always that bad?

 

gYYbQdJ.jpg

 

Donkey Kong lives on. Now I'm thinking AV mod .. the picture is dreadful!

 

5Lm0EDu.jpg


In Topic: Atari 400 - no sign of life - black screen

Sat Mar 31, 2018 4:32 PM

Pic 1. The RAM board contacts were clean, but the CPU ones very dirty - as you can see.

 

sci9vHO.jpg

 

 

This is the RAM board. Do the chips look normal? As in standard 16k setup?

 

QA8HN4q.jpg

 

 

The reverse side of the RAM board, with 4 wires connecting to an IC board on the motherboard

 

v0i3ndh.jpg

 

 

And the yellow / green pair of wires connecting to the underside of the cartridge connector.

 

x60Te2k.jpg

 

Lastly, what looks like an engineers label stating, possibly, that the machine is 48k? The label is a little cryptic - I'm assuming A400 is Atari 400, and 7/84 the date? Has anyone seen this before?

 

58gZ2Ay.jpg


In Topic: Atari 400 - no sign of life - black screen

Sat Mar 31, 2018 4:20 PM

Absolute top notch - thanks so much for the step by step instructions, really appreciated. I'm very impressed by the overall help offered on this website! You do it a great credit.

 

So, I carefully followed them. I had to laugh a little at step 2 - that was what had me stumped earlier. That cartridge door ...  :grin: 

 

I'm going to attach some pics (as promised, pics fans), but there seems to be something maybe a little unusual about the RAM board. It has soldered wires going to another IC on the board, and to the underside of the cartridge connector. Is this normal? The underside of the chassis has a red label saying '16k RAM', but also a hand written label saying '48k'. Inside there's what looks like an engineers label stating 'A400 48k' - could it have been upgraded? Pics to follow.


In Topic: Atari 400 - no sign of life - black screen

Sat Mar 31, 2018 12:03 PM

but in the case of the 400, it requires significant disassembly.   

 

You're absolutely right there - I'm a bit stumped already trying to carefully open the thing up. I have the bottom chassis off, but can't seem to get further ... any advice on how to disassemble the thing?