Tom-Cat Posted January 17, 2006 Share Posted January 17, 2006 Hi all ! I have a problem with an Atari 800XL. When I connect it to the TV via the modulator all I get on channel 13 is a completely black screen and on the channel 14 a black screen with jagged horizontal grey stripes (manically flashing)... No sound is output or anything. I tried disconnecting the keyboard, cleaning the motherboard, etc. but nothing worked. Is there a possibility of the modulator being broken and I should do the monitor (scart) cable ? What other things should I try to fix it ? Thanx for the answers ! Best regards, Tomaz Quote Link to comment Share on other sites More sharing options...
+Mitch Posted January 17, 2006 Share Posted January 17, 2006 Hi all ! I have a problem with an Atari 800XL. When I connect it to the TV via the modulator all I get on channel 13 is a completely black screen and on the channel 14 a black screen with jagged horizontal grey stripes (manically flashing)... No sound is output or anything. I tried disconnecting the keyboard, cleaning the motherboard, etc. but nothing worked. Is there a possibility of the modulator being broken and I should do the monitor (scart) cable ? What other things should I try to fix it ? Thanx for the answers ! Best regards, Tomaz 1001780[/snapback] What country are you in, not the US I take it? Mitch Quote Link to comment Share on other sites More sharing options...
Tom-Cat Posted January 17, 2006 Author Share Posted January 17, 2006 Slovenia (PAL ) Hi all ! I have a problem with an Atari 800XL. When I connect it to the TV via the modulator all I get on channel 13 is a completely black screen and on the channel 14 a black screen with jagged horizontal grey stripes (manically flashing)... No sound is output or anything. I tried disconnecting the keyboard, cleaning the motherboard, etc. but nothing worked. Is there a possibility of the modulator being broken and I should do the monitor (scart) cable ? What other things should I try to fix it ? Thanx for the answers ! Best regards, Tomaz 1001780[/snapback] What country are you in, not the US I take it? Mitch 1001792[/snapback] Quote Link to comment Share on other sites More sharing options...
Sikor Posted January 17, 2006 Share Posted January 17, 2006 Slovenia (PAL ) Hmm, Pal ataris work on 3rd and 4th channel. not 13-14teen... Maybe it is your problem? Some question: in AV connection working fine? Quote Link to comment Share on other sites More sharing options...
Tom-Cat Posted January 17, 2006 Author Share Posted January 17, 2006 It seems that they number channels differently in different TV models I will try building the AV conntection (Atari 800XL Monitor output -> SCART) today. Tomaz Quote Link to comment Share on other sites More sharing options...
Tom-Cat Posted January 18, 2006 Author Share Posted January 18, 2006 I made the AV Connection (Atari Monitor output -> SCART) and the same thing - BLACK screen. When one turns the Atari ON (or presses RESET) a grey screen (or sometimes a bit coloured screen) appears for a fraction of a second and then it goes to black... Quote Link to comment Share on other sites More sharing options...
Sikor Posted January 18, 2006 Share Posted January 18, 2006 So, you have problem with one from chips inside your Atari. Remove cover from computer, keyboard, metal ekran and put computer on. After few second you can put your finger from chip to chip - if any will be hotest than other - it is probably defected chip. Other thing will be with cold solder on someone chip. Good luck!!! Quote Link to comment Share on other sites More sharing options...
Tom-Cat Posted January 18, 2006 Author Share Posted January 18, 2006 I did try that and none of the chips ran hotter than others (well not significantly hotter anyway) - I had the problem of a faulty RAM chip on the ZX Spectrum which I identified this way and fixed. I checked around a bit for cold solder joints and couldnt find any... Quote Link to comment Share on other sites More sharing options...
Tom-Cat Posted January 25, 2006 Author Share Posted January 25, 2006 I dismatled the whole thing again yesterday and resoldered a bunch of places that looked like they might be cold (but it seems they weren't) - also pushed out and in all 5 socketed chips and cleaned everything up thorougly. The voltages on the chips seem OK though. Still Nothing (( Quote Link to comment Share on other sites More sharing options...
Rybags Posted January 25, 2006 Share Posted January 25, 2006 Can it boot a disk? Can you get the keyclick sound? If not, it will indicate that it's not just a simple modulator problem. Quote Link to comment Share on other sites More sharing options...
LYNXGUY Posted January 25, 2006 Share Posted January 25, 2006 Hey Tom-Cat, try all the channels on your TV to see what channel you have to be on and in the USA it is channel 2 Quote Link to comment Share on other sites More sharing options...
Tom-Cat Posted January 30, 2006 Author Share Posted January 30, 2006 (edited) I have tried with the TV Channels and the Monitor cable - the same thing... no keys work (but the picture quality changes a bit when I press and hold some of the function keys on the right). Only reset works and resets the machine (which can be noticed because the pictures goes greyish for a moment). Other keys produce no effect... Oh and I don't have a disk. The tape loader (when holding START on the reset) doesn't work though.... Edited January 30, 2006 by Tom-Cat Quote Link to comment Share on other sites More sharing options...
LYNXGUY Posted January 30, 2006 Share Posted January 30, 2006 Just a thought but is the switch box hooked up right ?? Is hooked up to the VHF not the UHF ??, just a thought Do you have the antenna hooked up to the switchbox ?? Quote Link to comment Share on other sites More sharing options...
MEtalGuy66 Posted February 14, 2006 Share Posted February 14, 2006 Heres another "not so common" problem, but one that Ive seen a few times with the 800xl: The rectification in the power supply is bad. This makes the machine produce REALLY STUNNING "modern art" on the screen when you turn it on, rather than the expected blue screen with the READY prompt. You can fix this by replacing the power supply unit, or having it repaired. Also, check that your oscilator crystal is in good shape. If the system is not operating at the proper frequency, you will also get "modern art" instead of an intelligable display. Everything in the ATARI is timing dependant on the scan rate of the TV/MONITOR standard that it is designed for (PAL/NTSC/SECAM, etc.) I would check these possibilities before buying replacement chips. As a side note, while we are on the subject of DC rectification, any 1050 drives you may have that are "dead" but the power LED on the front still comes on, 90% likely can be fixed by replacing a) the two diodes near the back of the board, b) any leaking, shorted, or bad capacitors, c)any broken traces (the boards are cheap and often delaminate due to heat over time), and d) the voltage regulators at the back of the drive, bolted to the heat-sink frame. You should replace the components in the order listed above. If you have bad diodes or caps, and you replace the regulators, often it will just fry the regulators again as soon as you power it up. If anyone is interested, I can provide test-points for measuring the 5v and 12v circuits within the drive to isolate which regulator is bad. Quote Link to comment Share on other sites More sharing options...
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