Atari 2600 does not power on

[mbc230]

I just purchased an Atari 2600 with no power issue. I have opened up the Atari and tested the power supply and it has 15v when just plugged in and I get 11.2 Volts from the Capacitor and then the same voltage when testing the Voltage Regulator as well. I even powered off the Atari and did another check the voltage dropped to next to nothing so I validated that the Atari does power off. I have looked at the board from front to back and on the front of the PCB and on the corner of the cover there is a capacitor that had a lot of solder like a block soldered to it. So I took my solder pump and removed all of it as well as cleaned up the solder joint and on the back of the Atari I noticed some black in color around the solder joint for that same capacitor. I did not measure the voltage yet or anything as I would like to know what the specs are to test each resistor or where to look next. Does anyone have any ideas? Thank you in advance.

[ChildOfCv]

3 hours ago, mbc230 said:

I get 11.2 Volts from the Capacitor and then the same voltage when testing the Voltage Regulator as well.

From both the input and the output of the regulator?!?!

[mbc230]

12 minutes ago, ChildOfCv said:

From both the input and the output of the regulator?!?!

No just the input side. The output side is less than 5 volts or so....

[ChildOfCv]

That's better then.  By "or so" do you mean that it's at least close to 5V?

[mbc230]

17 minutes ago, ChildOfCv said:

That's better then.  By "or so" do you mean that it's at least close to 5V?

It is really close like 4.8V. What should I check next?

[ChildOfCv]

Well, then it sounds like the system is at least powering on (just no indication since they thought fancy things like indicator lights were a luxury).

First question is, did you try reset?  Some cartridges don't do anything until you reset.

Has the Atari been modded or are you hooking it to the TV in the traditional way?  If so, does the static turn to a black screen when you flip the switch on?

[mbc230]

1 minute ago, ChildOfCv said:

Well, then it sounds like the system is at least powering on (just no indication since they thought fancy things like indicator lights were a luxury).

First question is, did you try reset?  Some cartridges don't do anything until you reset.

Has the Atari been modded or are you hooking it to the TV in the traditional way?  If so, does the static turn to a black screen when you flip the switch on?

No I did not reset it. How do you do that might I ask? There is no black screen at all....it is just good ol’ plain TV snow

[ChildOfCv]

Just now, mbc230 said:

No I did not reset it. How do you do that might I ask? There is no black screen at all....it is just good ol’ plain TV snow

There's a reset lever along the row of switches, along with B/W/Color, possibly player difficulty selectors, etc.  But until you have signal, that doesn't matter.

 

Does the channel selection between the 2600 and the TV match?  If the unit has a channel switch on the bottom, it's probably 2 or 3.  If not, then it's 3.  Also, the TV must still be compatible with the ancient NTSC (or PAL?) analog standard or it will probably ignore the signal altogether anyway.

[mbc230]

1 minute ago, ChildOfCv said:

There's a reset lever along the row of switches, along with B/W/Color, possibly player difficulty selectors, etc.  But until you have signal, that doesn't matter.

 

Does the channel selection between the 2600 and the TV match?  If the unit has a channel switch on the bottom, it's probably 2 or 3.  If not, then it's 3.  Also, the TV must still be compatible with the ancient NTSC (or PAL?) analog standard or it will probably ignore the signal altogether anyway.

That lever and yes I hit that switch anad made sure the channel matched the channel on the TV. The TV is a 13 year plasma TV and I also bought a new RF Modulator for it as well. Do you think the TV is the issue? Thank you for all your help.

[ChildOfCv]

Can't say for sure yet.  If you have other consoles, VCRs or things that can output on channel 3, and they work on the TV, then it's probably okay.

 

You could check the coax from the Atari to the switcher.

 

But doesn't your TV have a coaxial input?  Most of those ancient switch boxes use 300-ohm outputs, while the TV's 75-ohm coaxial input should be a direct match for the Atari's output.  You can buy an RCA to F type coax adapter to plug your Atari straight into the TV.

 

[mbc230]

1 minute ago, ChildOfCv said:

Can't say for sure yet.  If you have other consoles, VCRs or things that can output on channel 3, and they work on the TV, then it's probably okay.

 

You could check the coax from the Atari to the switcher.

 

But doesn't your TV have a coaxial input?  Most of those ancient switch boxes use 300-ohm outputs, while the TV's 75-ohm coaxial input should be a direct match for the Atari's output.  You can buy an RCA to F type coax adapter to plug your Atari straight into the TV.

 

How do I check the coax from the Atari switcher? My TV does have a coax jack input in it. I did purchase one of those coax to f type adapters. 

[ChildOfCv]

54 minutes ago, mbc230 said:

How do I check the coax from the Atari switcher? My TV does have a coax jack input in it. I did purchase one of those coax to f type adapters. 

Make sure there is continuity between the outside contacts on both ends.  Then again with the inside contacts.  Now make sure there is no continuity between inner and outer.

 

Now plug it into the Atari.  You should now see around 100 ohms between the outer and inner contacts on the other end.

[mbc230]

2 hours ago, ChildOfCv said:

Make sure there is continuity between the outside contacts on both ends.  Then again with the inside contacts.  Now make sure there is no continuity between inner and outer.

 

Now plug it into the Atari.  You should now see around 100 ohms between the outer and inner contacts on the other end.

I did test out the RCA end on the board and the RCA cable and I get roughly 102.4 ohms on both. This is a head scratcher let me tell you.

[ChildOfCv]

Do you know if other RF-type devices work on that TV?  Because if so, then all signs point to the RF modulator on the Atari not working.

 

There would be a couple easy checks to make there too, but first we need to know, how many pins connect it to the board?  If it's 5 pins, check voltage between ground and pin 3 (the middle one).  If it's 4 pins, check between ground and pin 2.  If the voltage is near 5V there, but you get no signal, then something in the RF box is dead.  Could be a broken inductor wire or a dead LM3086.

[mbc230]

10 hours ago, ChildOfCv said:

Do you know if other RF-type devices work on that TV?  Because if so, then all signs point to the RF modulator on the Atari not working.

 

There would be a couple easy checks to make there too, but first we need to know, how many pins connect it to the board?  If it's 5 pins, check voltage between ground and pin 3 (the middle one).  If it's 4 pins, check between ground and pin 2.  If the voltage is near 5V there, but you get no signal, then something in the RF box is dead.  Could be a broken inductor wire or a dead LM3086.

Well I apologize and I feel dumb. It turns out the new RF modulator coax end the copper pin was bent and was not making contact with the female end in the TV. See attached picture. Thank you for all your help and the useful information. I will post a follow up once my RCA to coax jack arrives. Thanks again.

[mbc230]

On 7/16/2019 at 11:01 PM, ChildOfCv said:

Do you know if other RF-type devices work on that TV?  Because if so, then all signs point to the RF modulator on the Atari not working.

 

There would be a couple easy checks to make there too, but first we need to know, how many pins connect it to the board?  If it's 5 pins, check voltage between ground and pin 3 (the middle one).  If it's 4 pins, check between ground and pin 2.  If the voltage is near 5V there, but you get no signal, then something in the RF box is dead.  Could be a broken inductor wire or a dead LM3086.

Well Good News I got the RCA coax jack and bam the Atari works. I played several games with no issues and then an issue occured. I was is in the middle of playing Atlantis and it just randomly started selectling levels on its own. Now every game I install it starts just starts selecting levels. What do you think is going on? Goes from working wonderfully to randomly selecting levels. What should I do to fix this? Thank you in advance. Cheers!

[+-^CrossBow^-]

3 hours ago, mbc230 said:

Well Good News I got the RCA coax jack and bam the Atari works. I played several games with no issues and then an issue occured. I was is in the middle of playing Atlantis and it just randomly started selectling levels on its own. Now every game I install it starts just starts selecting levels. What do you think is going on? Goes from working wonderfully to randomly selecting levels. What should I do to fix this? Thank you in advance. Cheers!

Got to be a short in the level select switch most likely? Perhaps the spring that pulls the switch back up came loose inside the switch? I've had that happen on a light 6 switcher once. I could never get the spring to sit properly and just replaced the switch from another dead donor parts 2600.

 

[+DrVenkman]

13 hours ago, mbc230 said:

Well Good News I got the RCA coax jack and bam the Atari works. I played several games with no issues and then an issue occured. I was is in the middle of playing Atlantis and it just randomly started selectling levels on its own. Now every game I install it starts just starts selecting levels. What do you think is going on? Goes from working wonderfully to randomly selecting levels. What should I do to fix this? Thank you in advance. Cheers!

 

10 hours ago, -^Cro§Bow^- said:

Got to be a short in the level select switch most likely? Perhaps the spring that pulls the switch back up came loose inside the switch? I've had that happen on a light 6 switcher once. I could never get the spring to sit properly and just replaced the switch from another dead donor parts 2600.

 

Likely it’s the switch but there’s an outside shot it could be a short along the line to the RIOT or a bad RIOT chip itself. The console switches are read by the RIOT. I’ve had two 4-switch units with bad RIOTs - the only symptoms were that the system wouldn’t read certain switches or that they “stuck” in one position or the other regardless of switch position. It’s either Pin 23 or 24 of the RIOT, I don’t recall which - the official Atari VCS Domestic Field Service manual has schematics for each variant of the 6-switch and 4-switch models but the schematics are inconsistent. One page shows pin 23, another shows pin 24. Should be easy to trace with meter. 

[mbc230]

3 hours ago, DrVenkman said:

 

Likely it’s the switch but there’s an outside shot it could be a short along the line to the RIOT or a bad RIOT chip itself. The console switches are read by the RIOT. I’ve had two 4-switch units with bad RIOTs - the only symptoms were that the system wouldn’t read certain switches or that they “stuck” in one position or the other regardless of switch position. It’s either Pin 23 or 24 of the RIOT, I don’t recall which - the official Atari VCS Domestic Field Service manual has schematics for each variant of the 6-switch and 4-switch models but the schematics are inconsistent. One page shows pin 23, another shows pin 24. Should be easy to trace with meter. 

That is awesome information and thank you very much. I did let the Atari sit for a couple hours and well it started working fine again with no issues. It could be what you mentioned above. Thoughts?

[mbc230]

14 hours ago, -^Cro§Bow^- said:

Got to be a short in the level select switch most likely? Perhaps the spring that pulls the switch back up came loose inside the switch? I've had that happen on a light 6 switcher once. I could never get the spring to sit properly and just replaced the switch from another dead donor parts 2600.

 

The switch seems like it springs back with no issues. What do you think? Thank you.

[+DrVenkman]

10 minutes ago, mbc230 said:

That is awesome information and thank you very much. I did let the Atari sit for a couple hours and well it started working fine again with no issues. It could be what you mentioned above. Thoughts?

Well, you can have an intermittent connection issue in either the switch or along the signal path from the switch to the RIOT chip. Start by taking the machine apart again if you’ve put it back together and cleaning the crap out of the switch. I usually just spray Deoxit or other electrical contact cleaner into it and cycle it several times to spread the cleaner around to all surfaces. Let it dry and see if the problem reoccurs. If it doesn’t after an hour or more of system use, it was probably just a dirty/oxidized switch. If it does come back, it’s time to see if the switch works using your multimeter and tracing the signal all the way down to the RIOT. You can actually turn on the Atari and measure the I/O pins on the RIOT (see the various schematics available online) - watch to see if they change from high to low or vice versa when you move all the switches. 

[mbc230]

8 hours ago, DrVenkman said:

Well, you can have an intermittent connection issue in either the switch or along the signal path from the switch to the RIOT chip. Start by taking the machine apart again if you’ve put it back together and cleaning the crap out of the switch. I usually just spray Deoxit or other electrical contact cleaner into it and cycle it several times to spread the cleaner around to all surfaces. Let it dry and see if the problem reoccurs. If it doesn’t after an hour or more of system use, it was probably just a dirty/oxidized switch. If it does come back, it’s time to see if the switch works using your multimeter and tracing the signal all the way down to the RIOT. You can actually turn on the Atari and measure the I/O pins on the RIOT (see the various schematics available online) - watch to see if they change from high to low or vice versa when you move all the switches. 

Thank you. I will try this out when I get a moment and post the results. Cheers!