Intellivison Crashes Randomly

[Tempest]

My Intellivison has developed a problem.  It appears that after a random period of time (could be a minute, might be ten) whatever game I'm playing will crash.  If I'm using the LTO flash it will go back to the menu but if it's a regular cartridge it will just crash.  I've tried several different games from Burgertime to the Test Cartridge to various demos and they all crash after a time.  Sometimes the crash will happen several times in a row in a short time (seconds) other times it might run for 20 min or so.  
 

I'm at my wits end trying to figure this out.  I'm wondering if it has something to do with the RGB mod I just had installed, but it happens through composite too.  I suppose it could be a power issue, but the person who installed my mod said he had it running for several hours with no issues.  Any ideas?

[+stupus]

It usually seems they do this when they get too hot. I assume the heat slowly damages the chips. I always run a fan anymore on mine when i use them., and try to elevate them off a solid surface. This seems to help avoid this from happening and ones that have this issue seem to work for a longer time if they are kept cool.

To permanently fix it i assume its going to be figuring out what chips may be damaged but i cant help there. Somebody else might have some ideas on which to check first. Its too bad they ever put the power supply inside the tight case.

Edited June 15, 2021 by stupus

[Tempest]

The area around the power supply is pretty warm, but I think that's par for the course on an Intellivision.  I wonder if the diagnostic cart can detect a bad chip?  I didn't notice any game playing oddly or doing anything weird before they crashed, it was just suddenly 'bam' they crashed.  I'd think if a chip was damaged or bad the game wouldn't play right up to that point.

[+-^CrossBow^-]

20 minutes ago, Tempest said:

The area around the power supply is pretty warm, but I think that's par for the course on an Intellivision.  I wonder if the diagnostic cart can detect a bad chip?  I didn't notice any game playing oddly or doing anything weird before they crashed, it was just suddenly 'bam' they crashed.  I'd think if a chip was damaged or bad the game wouldn't play right up to that point.

While not the same as you are getting. One of my Intelly 2 units I was testing Crayon's board with looked great when first powered on. Then within a min the graphics would start to streak to one side and bleed. A few min later, actual sprites would start to fade in and out.

 

The Diagnostics rom stated everything was good to go. But in the end it was the STIC causing the issue. I replaced it out with one from a model 1 and the issues all went away. I had to remove the original socket it was in because the older STIC with the heatsink on it, wouldn't fit until I did that. So yeah... you can have a chip that works or seems to work at first and then it gets hot enough to a point to up and fail.

 

We will get it sorted.

 

[+DamonicFury]

I got a useful tip once when trying to repair an arcade game.  Try taking an ice cube, wrapped in plastic to prevent moisture, and touching it to each chip for long enough to see if the problem resolves.  This method successfully detected which RAM chip was being problematic in my machine and it was a relatively simply matter to replace it.  Perhaps this might work here as well.

[+-^CrossBow^-]

Will be able to call this one way or the other tomorrow night. But it looks like between the time it left the 'Tower' a week ago to when Tempest got it, the 3906s are failing. Which one I don't know and I didn't care as I replaced them both along with the 12Ω power resistor as his original was starting to flake its ceramic and looking generally not well. The resistor was not the issue as I replaced it first and the problem still persisted. It wasn't until I replaced out the 3906s that it seems to now be running stable again.

 

For the record, the exact issue I was getting when it arrived back to me was that it would come up and work fine, but only for a little bit as eventually it would usually reset itself back to the LTO menu on pretty much anything I tried to play. A few games would lock up like Mystic Castle after a few min randomly. But it just ran some test demos for over an hour without any issue and then I fired up and played about a half dozen screens of Diner on difficulty level 2 without any issues. 

 

Stupid 3906s... pretty much they all need to be replaced out at this point and I'm going to see about having Console5 start providing them in the cap kits just because they are cheap and no more difficult to replace than the caps already are.

 

[+-^CrossBow^-]

Turns out C5 already has the option to have both the 12Ω power resistor and the 3906s added when ordering cap kits. So I would advise anyone that decides to work on or recap their intellivisions, to replace both 3906s near the CPU on the main board and the 12Ω resistor on the power board for good measure. 

 

When you install those 3906s, try and keep the ferrite beads from the originals if you can but I've seen plenty of Intellivision model 1 units that didn't have them and they were working fine. Also, do NOT install those 3906s close to the PCB. Install them about a half inch off the board to help with heat dissipation.