Atari 800 display issues

[bernie]

I just bought an atari 800 of craigslist in "unknown" condition.

 

I purchased a monitor->composite cable (that my friend tested) and plugged it in to my Vizio 65" LED tv. Unfortunately I get a "no signal" (and no sound).

 

The 800 powers on (red light) and if I remove the cartridge (I tested with two) I hear clicks when I press the keyboard, so something must be working...

 

Any ideas of next steps to troubleshoot? I just ordered an RF adapter so that I can plug into antenna switch.

 

Unfortunately this is the only machine I have that uses Composite input.

 

Thanks!

B.

Edited March 5, 2017 by bernie

[russg]

I just bought an atari 800 of craigslist in "unknown" condition.

 

I purchased a monitor->composite cable (that my friend tested) and plugged it in to my Vizio 65" LED tv. Unfortunately I get a "no signal" (and no sound).

 

The 800 powers on (red light) and if I remove the cartridge (I tested with two) I hear clicks when I press the keyboard, so something must be working...

 

Any ideas of next steps to troubleshoot? I just ordered an RF adapter so that I can plug into antenna switch.

 

Unfortunately this is the only machine I have that uses Composite input.

 

Thanks!

B.

Let's see. You have the ROM card in front slot, at least one RAM card in behind the ROM. You have

the cartridge door shut. Your cartridge is in the left slot. ? there is no RF port, where you gonna

get a RF output? You ordered a RF adapter. Does that provide RF from the 5 pin monitor port?

Or maybe PAL 800 has RF. I'm in NTSC land. No, sorry, the RF comes out the center of the

back via a RF cable. Your RF adapter goes on the TV.

Edited March 5, 2017 by russg

[bernie]

Let's see. You have the ROM card in front slot, at least one RAM card in behind the ROM. You have

the cartridge door shut. Your cartridge is in the left slot. ? there is no RF port, where you gonna

get a RF output? You ordered a RF adapter. Does that provide RF from the 5 pin monitor port?

 

 

Yes. I have 48k of ram and the the ROM in the back (which I removed and reseated), a cartridge in the left slot (tried several), and the cartridge door closed (so the power light comes on).

 

I have 5 pin monitor port to composite (RCA) lead and get no signal on the TV.

 

If I remove the cartridge, and reset, If I press any of the keyboard keys I hear click (I assume I'm in Memo).

 

I tried plugging in the audio part of the cable into a stereo and I hear some chirping when the atari is powered on and off.

 

I am waiting for adapter to allow me to plug into antenna in (c2/3) on my TV.

 

 

 

 

 

I

[russg]

 

 

Yes. I have 48k of ram and the the ROM in the back (which I removed and reseated), a cartridge in the left slot (tried several), and the cartridge door closed (so the power light comes on).

 

I have 5 pin monitor port to composite (RCA) lead and get no signal on the TV.

 

If I remove the cartridge, and reset, If I press any of the keyboard keys I hear click (I assume I'm in Memo).

 

I tried plugging in the audio part of the cable into a stereo and I hear some chirping when the atari is powered on and off.

 

I am waiting for adapter to allow me to plug into antenna in (c2/3) on my TV.

 

 

 

 

 

I

The 10K ROM has to be in the front slot. The cartridge has to be in the left slot. The

cart door has to be shut.

Edited March 5, 2017 by russg

[Mclaneinc]

Was the comp lead tested on an Atari?

[bernie]

The 10K ROM has to be in the front slot. The cartridge has to be in the left slot. The

cart door has to be shut.

 

Yes, that's how I tested.

[bernie]

Was the comp lead tested on an Atari?

No, just with a meter to ensure the wiring is correct

 

Unfortunately, I only have one Atari.

Edited March 6, 2017 by bernie

[electronizer]

Do you have the 5-pin DIN to 4 RCA plug version of the cable? Have you tried connecting each of the 4 RCA plugs to composite video in on your TV just to make sure it isn't wired differently than expected?

[russg]

 

Yes, that's how I tested.

I'm sure you have tested the power supply brick. The plug should be about 10.6 volts AC with no load on it.

It supplies 5 v dc, inside the computer I think. That's with a NTSC power brick.

[bernie]

I'm sure you have tested the power supply brick. The plug should be about 10.6 volts AC with no load on it.

It supplies 5 v dc, inside the computer I think. That's with a NTSC power brick.

 

I haven't. I tested with 2 power supplies but I can test with my friend's multimeter tonight. Where should I test inside the computer?

[bernie]

Do you have the 5-pin DIN to 4 RCA plug version of the cable? Have you tried connecting each of the 4 RCA plugs to composite video in on your TV just to make sure it isn't wired differently than expected?

No, I have the three RCA version (with two audios joined)

[bernie]

In summary, here is where I am now:

The 800 powers on (red light) and if I remove the cartridge (I tested with two) I hear clicks when I press the keyboard (in memo?), so something must be working...

The monitor->composite cable gets a "no signal" (and no sound comes out if I hook to stereo) I tried plugging in the audio part of the cable into a stereo and I hear some chirping when the atari is powered on and off.

Through RF (via RCA->Antenna adapter I got today) I get no signal on my TV

I unplugged/reseated Ram/combination of RAM in the back

I have tried several cartridges in the left slot with the cartridge door closed (so the power light comes on).

I tried several different power adapters

I tried a basic take apart, and there is no visible damage/spillage internally

-----------------------------

What I plan to do:

1. Test power adapters with multimeter

2. Test internal voltages

------------------------------

Questions:

1. How do I unplug the keyboard

2. Where should I test internal voltage

3. Since I'm getting the power light, and when I press the keyboard with no cartridges I get sounds to indicate keypresses; something must be working. How can I isolate if it's the PSU board, or the main board, or the personality board?

4. Anything else I should try?

[+Stephen]

One thing you can try, is press ctrl+2. It should generate a very annoying buzz from the speaker rather than just the normal keyclick. It seems like the overall machine is working, given the fact that you are generating keyclicks.

[R.Cade]

I can almost guarantee you have the wrong video cable... There are several computers that use that same cable (Commodore VIC, C64, TI994/A, Sega Genesis, Atari, and even generic MIDI) and wiring is different on most all of them.

Edited March 7, 2017 by R.Cade

[bernie]

One thing you can try, is press ctrl+2. It should generate a very annoying buzz from the speaker rather than just the normal keyclick. It seems like the overall machine is working, given the fact that you are generating keyclicks.

 

 

Thanks for the tip ctrl+2 does generate a very annoying buzz.

[bernie]

I can almost guarantee you have the wrong video cable... There are several computers that use that same cable (Commodore VIC, C64, TI994/A, Sega Genesis, Atari, and even generic MIDI) and wiring is different on most all of them.

 

It may be. I'd be confident of that if I was able to get a signal from the RF though...

[R.Cade]

 

It may be. I'd be confident of that if I was able to get a signal from the RF though...

 

Sure. Those switchboxes are always hanging around in old boxes of wires.

[bernie]

 

Sure. Those switchboxes are always hanging around in old boxes of wires.

 

 

I used an RCA Female to F-Type Coax Male Adapter that arrived in the mail today from Amazon and unfortunately, this did not work.

[R.Cade]

What did you get, on Channel 3/4? That's very odd for the computer to come up and make noises but no video out...

[+kheller2]

Your adapter for RF is RCA to F connector? And the long black cord from the 800 connects to that and you tuned the TV to channel 3? Make sure tv is not auto scanning and you manually picked standard and not hd signals.

[bernie]

What did you get, on Channel 3/4? That's very odd for the computer to come up and make noises but no video out...

 

I think it's channel 2/3

 

Yes, I tried to tune on channels 2/3 flipped the switch and nothing

[bernie]

Your adapter for RF is RCA to F connector? And the long black cord from the 800 connects to that and you tuned the TV to channel 3? Make sure tv is not auto scanning and you manually picked standard and not hd signals.

 

Correct. I had 2/3 pre-programed from when I had cable plugged in directly and nothing. I switched to antanna mode and unfortunately even when trying to add channels 2/3 manually my TV does not find a signal to add them. I will try on my friend's TV tonight.

Edited March 7, 2017 by bernie

[bernie]

So progress... I bought an old 20" CRT TV to test (authentic experience lol?) and I basically see a cycling image of the memo pad:

 

 

 

https://www.dropbox.com/s/d3ewi62uyw2nz6r/IMG_1871.jpg?dl=0

Via Monitor out cable

 

https://www.dropbox.com/s/6ovqwyzovkri7u7/IMG_1873.jpg?dl=0

 

Via RF

 

Any ideas how to fix?

[sorry I couldn't get the images to work]

Edited March 7, 2017 by bernie

[R.Cade]

Does the CRT work with other known good video sources?

[+DrVenkman]

Given the problems you're having across multiple TVs, I'm pretty sure you've got an issue with one fo the main chips, probably ANTIC, GTIA or the 6502.