130 XE - video problem

[goran]

Bonjour tout le monde !

 

First, a short introduction. My first computer was an Atari 400 (in 1983) with the famous keyboard .The next computer was a CPC 6128. The third computer was a 1040 STF . After, there was my PC era.

Today, I'm the proud owner of :

* 1 TT/030 (my favorite computer)

* 1 Mega STE

* 1 1040 STE

* 1 1040 STF

* 2 Amiga 1200 (great computers, even if I prefer Atari)

* 2 800XL

* 1 130XE (with small video problems)

* .... and some PCs/Macs

 

And now, my problem : The 130XE produces a lot of garbage on screen when I turn it on. The screen is unable to stabilize for about two minutes. After the border of the screen is brown and not black as expected. If I switch to mono, everything is OK.

I touched all components to find one overheated. I droped the 130XE on the floor. The problem remained. By touching all the components, I found that the screen returned to a correct display when I put my finger on C57. Here is a picture of the nasty guy.

I used a small screwdriver to turn it clockwise, then display returned to a better aspect.

 

The Atari 130XE is a French SECAM model.

 

My questions are very simple : Is there something I need to check ? Can something goes wrong ? Is there a way to verify that the C57 is correctly set ?

 

Thank you for your help.

[+bob1200xl]

First - I know nothing about SECAM...

 

The 74LS624 IC in your picture is a phase locked oscillator which is probably tuned by C57. Touching C57 adds the capacitance of your body to whatever it's set at. So, I would venture a guess that C57 needs to be adjusted a little bit. I would turn it one way until it drops out of sync (screen gets messy), turn it the other way until it drops sync on the other extreme and then set it half way between those two points. This is a lock adjustment (I think) so it would be best if you powered off as you were searching for the endpoints - see if it can lock when you power on.

 

Bon chance! <==== the limit of my high school French...

 

Bob

 

 

Bonjour tout le monde !

 

First, a short introduction. My first computer was an Atari 400 (in 1983) with the famous keyboard .The next computer was a CPC 6128. The third computer was a 1040 STF . After, there was my PC era.

Today, I'm the proud owner of :

* 1 TT/030 (my favorite computer)

* 1 Mega STE

* 1 1040 STE

* 1 1040 STF

* 2 Amiga 1200 (great computers, even if I prefer Atari)

* 2 800XL

* 1 130XE (with small video problems)

* .... and some PCs/Macs

 

And now, my problem : The 130XE produces a lot of garbage on screen when I turn it on. The screen is unable to stabilize for about two minutes. After the border of the screen is brown and not black as expected. If I switch to mono, everything is OK.

I touched all components to find one overheated. I droped the 130XE on the floor. The problem remained. By touching all the components, I found that the screen returned to a correct display when I put my finger on C57. Here is a picture of the nasty guy.

I used a small screwdriver to turn it clockwise, then display returned to a better aspect.

 

The Atari 130XE is a French SECAM model.

 

My questions are very simple : Is there something I need to check ? Can something goes wrong ? Is there a way to verify that the C57 is correctly set ?

 

Thank you for your help.

[goran]

Thank you Bob.

 

I fixed my problem with two wonderful tools : a small screwdriver and the best color calibration tool ever made, eyes.

I admit that I also used an Atari Artist cartridge to obtain nice colors.

 

Goran