telegames 2600 switches itself off

[atariactionman]

Hi, I have recently gotten hold of a gorgeous telegames video arcade and have been happily playing away, but recently my console has decided to switch itself off. My telly goes blank. If I switch it off and back on it will reawaken but then will switch off again.

My research on this fabulous site is telling me it is either the voltage regulator or the tia chip,

It is a modded system so its not the rf unit. And I use a harmony cartridge.

any help from you would be most appreciated. I am not a tech boffin but can do some small soldering jobs. But want to be sure before I commence.

[electromaster_84]

The harmony cartridge draws power from the system, so it could be stressing the voltage regulator if its a little weak already. You could try playing a normal cartridge and seeing if the same behavior occurs. The best way to know for sure would be to use a multimeter and measure the voltage from the regulator. Also it could be a bad/cracked solder joint somewhere on the board, and when it heats up it loses connection. If it is a bad solder joint I would think the most likely areas to look for one would be the power jack, power switch, and cartridge slot. All of these areas see stress, and over the years one of the solder joints could have failed. One other thing to check would be the power switch, they can get dirty and have poor contact. The way I always check these is to power up the system, and give the switch a gentle wiggle up/down and side to side. Don't use enough force to throw the switch, but enough for the contacts inside the switch to move a little. If the screen glitches, the system shuts off, or anything out of the ordinary happens the switch is bad. If that's the case you can either desolder and clean the switch, or buy a new one.

 

If it were me I would recap the board (new capacitors), and replace the voltage regulator with a higher amperage equivalent (7805cv 1.5 amp). If the chips (TIA, RIOT, and CPU) are socketed i would pull the chips, and clean them.

Edited April 16, 2016 by electromaster_84

[+Stephen Moss]

I could understand it being a switch problem if the unit does not power up every time but I would think it unlikely that once a switch contact has been made it would disconnect of its own accord with out either it or the console being physically moved/jogged.

 

It could be the regulator going into thermal shutdown so check that first, you should get around 9V DC in and 5V DC out when working and generally between 1.5 and 3V DC out when in shutdown.

I am not sure using a higher amperage regulator would help, while it is true that it could output more power the output power in not the issue, when it comes to thermal shutdown it is power dissipation that is the issue. While I have not checked the data sheet I would expect the permitted power dissipation without a heatsink to be the same for both devices as it is limited by the design of the TO-220 package thus using a higher current regulator would be of no advantage.

 

If the regulator is going into thermal shutdown there are three possibilities...

1) The regulator is defective - replace it

2) The heatsink compound/thermal paste whatever you want to call it has dried out and is no longer efficiently conducting the heat from the device into the heatsink copper area of the PCB - replace the paste, thermal pads are cheaper and less messy and as you need to remove the regulator anyway you may want to consider replacing it at he same time.

3) There is a problem elsewhere in the console that is consuming more current that it should, creating more power dissipation resulting in thermal shutdown in which case you need to find and replace the faulty component. Initially you could try the sniff/finger test, does something smell/feel hot or measure the input voltage as more current consumption = more voltage drop in the transformer so if the input voltage is clearly lower than it should that is probably a good indicator that your console has this type of problem.

 

You should also check my post at http://atariage.com/forums/topic/246217-help-troubleshoot-2600-resetting/#entry3380755 for places to check for bad solder joints.

 

[electromaster_84]

 

 

I am not sure using a higher amperage regulator would help, while it is true that it could output more power the output power in not the issue, when it comes to thermal shutdown it is power dissipation that is the issue. While I have not checked the data sheet I would expect the permitted power dissipation without a heatsink to be the same for both devices as it is limited by the design of the TO-220 package thus using a higher current regulator would be of no advantage.

 

To be clear the only reasons i suggested using a higher amperage voltage regulator were as follows

1) The original regulator is over 30 years old, and I would replace it anyway if it was suspect.

2) the op is using a harmony cart, and that draws a little more power from the system.

 

Other than that it sounds like you know the Atari 2600 better than me, so I would suggest the op check out that post you linked. I would still suggest replacing all electrolytic capacitors, voltage filtering cap (green chicklet near the regulator), and the voltage regulator itself. There are kits out there that can be had for under $10.00 that come with all the parts I mentioned, and more. http://console5.com/store/atari-2600-total-refresh-kit-new-capacitors.html

[atariactionman]

Thanks for all your help it is very appreciated. A great site and fantastic member base. Thanks again.

When I get the time to properly investigate I will let you know the outcome.

[+Stephen Moss]

 

2) the op is using a harmony cart, and that draws a little more power from the system.

 

In that case it is possible the extra current consumption might tip the regulator over the edge into thermal shutdown although I would think that unlikely as I am sure it would be a well known issue by now if that were the case and I do not recall hearing about it. However, if that is the issue then the simple addition of a small 10 or 20 degree C/Watt heatsink to the regulator should help dissipate the additional heat the heastsink will fit inside the case.

[electromaster_84]

I agree that the harmony cart is probably not at fault here, and would not cause any problems unless the regulator was on it's way out already. Come to think of it are the regulators in those models the kind with a heatsink clipped/bolted to them instead of being bolted to the board? If so I would check the solder points on the regulator and see if one or more have cracked, and make sure the heatsink is securely connected to the regulator.

[atari2800man]

Could it be that maybe the console inside may have collected dust to the point where it interferes with the electrical current of the atari 2600?