INTV works for a time, then screen goes black

[Loccy]

Hi all, Atarian reporting in again with his INTV on the side. 

 

She's still being a bit stroppy, unfortunately. The machine will work for a time before the screen just goes black. Powering it off and on will usually bring it back for a time, until eventually it goes black again.

 

Any ideas? I've seen people on Reddit suggesting cleaning the cartridge port, but that doesn't make much sense to me - surely it'd work, or it wouldn't?

 

And if that is a legit suggestion, any recommendations on HOW one can clean the cartridge port?

Edited February 3 by Loccy

[mr_me]

Will it come back on immediately, or does it need to rest a few minutes?

[+nanochess]

It sounds like a heating problem for me. I could suggest putting a laptop ventilator base under your Intellivision, and measuring the time it takes to go black.

[Loccy]

6 hours ago, mr_me said:

Will it come back on immediately, or does it need to rest a few minutes?

It generally comes back on immediately. But my gut feeling is that it gets worse with time, i.e. it lasts an increasing shorter and shorter period of time with each passing power cycle. Then the next day it'll be back to where it was. But that might be me just looking for it (I've not done any scientific timing!)

 

4 hours ago, nanochess said:

It sounds like a heating problem for me. I could suggest putting a laptop ventilator base under your Intellivision, and measuring the time it takes to go black.

If it is a heating problem, what is the most practical solution?

[Loccy]

2 minutes ago, Loccy said:

It generally comes back on immediately. But my gut feeling is that it gets worse with time, i.e. it lasts an increasing shorter and shorter period of time with each passing power cycle. Then the next day it'll be back to where it was. But that might be me just looking for it (I've not done any scientific timing!)

 

If it is a heating problem, what is the most practical solution? Recapping power supplies is perhaps somewhat out of my hardware league

 

[HunterZero]

Even though the thermal properties of the Intellivision are terrible, it should not normally overheat and crash to black screen unless there's an issue.

 

Does this happen with all cartridges?

 

* Clean the cartridge socket with Deoxit or isopropyl alcohol.

* Check the power board output voltages are stable

* Check the power ribbon cable is not defective

 

If none of these work then you are going to have to open the logic board sarcophagus for the next steps...

 

* Replace the transistors Q1 and Q2 near the CPU (2N3906 PNP)

* Check capacitor C26 (1uF, 20V) near pin 14 on the STIC

* Otherwise it sounds like a thermal problem with an IC, once it heats up. You are going to need to try replacing ICs with known good ones carefully, one at a time. Suggested order is: RA-3-9600 RAM, AY-3-8915 sound chip, AY-3-8900 STIC, CP-1610 CPU

 

- HZ

[The Eyeball Mural]

I agree that overheating is to be suspected. Is it an Intellivision or an Intelivision II? In my experience (back in the day) the II was more prone to this problem, but the experts (who have posted good advice above) know better than I would whether that is true or not. At the risk of seeming stupid, have you made sure to keep the console from being crowded by other objects? Books or other consoles around your Intellivision could inhibit airflow. I used to (again, back in the day) sequester my Intellivision II on a bookshelf to protect it from my cats causing accidental resets, so I could maintain a game state. If I crowded the console with books it would get hot and I would have to power down and lose my "saved game", but if I kept the airflow around it unimpeded I could leave the console on for weeks at a time and keep playing the same game, and never have any trouble. 

[Loccy]

So, I've observed it a little more closely. Up until now, I've left it on while I've been doing other things, usually at the Astrosmash title screen, and have come back to the black screen. Observing it, after a while the picture seems to break up quite impressively, flashing colours, like a loose RF connection, enough to make me go "blimey, think I'd better turn that off before it goes kaboom". So, I don't know whether that was a precursor to the black screen, or whether that is something new.

 

But having opened it up, it doesn't look terrible. There is one component that looks like it is leaking gunk (in the third pic, on what I assume is the main motherboard), but all the big power supply capacitors look pretty fresh to the eye.

 

I am pretty much out of my depth at this stage, though. Is it worth buying another "untested" on eBay UK? There's plenty of those, and there's another one that apparently works but only gives a black and white screen output. Perhaps by their powers combined they could be Captain Intellivision?

 

Edit: I bought the second one. Let's see how that goes...

 

Edited February 4 by Loccy

[HunterZero]

That's not leaking gunk from that crystal part, that's ancient glue. Quite common.

 

I see your sound chip isn't socketed, that would make it not trivial if you need to try to change that part. I would try swapping the STIC (and possibly CPU) before trying to replace the sound chip, given your latest description.

 

Note that for a PAL Inty (that daughterboard is for generating PAL colour signal), the STIC part is AY-3-8900; the NTSC spec USA 2609 console STIC is different, with part AY-3-8900-1.

 

- HZ

Edited February 4 by HunterZero

[+-^CrossBow^-]

@Loccy The 'gunk' is just glue. That is the crystal for the main system clock timing and excessive stress can break the crystal so the glue was used to hold it steady in place to minimize that. 

 

What I would do is to unscrew the two voltage regulators on the power supply board and clean up any left over old thermal paste both on the regulators and the heatsinks they are attached to. Then apply some new thermal paste to the regulators themselves. Don't need a bunch just a little bead is enough in most cases. When you tighten the regulators back down onto the heatsinks, they should be tight enough to see some of the paste just start to seep out the sides from the pressure.

 

If the twin 3906 transistors were the issue, they usually are just burn out immediately and don't usually work and then fail over time. But... one thing you do need to look for is to try and inspect all of the solder joints. It could be that once everything heats up, that a loose or cold solder joint starts to separate more and that causes the condition you see.

 

I'm not familiar with the PAL consoles so not sure exactly where you should look for such a possible issue. Other than to say to look at all of them closely on the bottom of the PCB for each of the larger main chips first.

 

[HunterZero]

Could even just replace the two regulators with new ones, they are cheap. They do get quite warm.

 

I have had broken and cold solder joints around the two large capacitors on the power board too. Give them a reflow. They are usually glued to the board, again to prevent the solder cracking.

 

- HZ

Edited February 5 by HunterZero

[vintagegamecrazy]

Buy some freezer spray. Spray the chips while it's being used and see if it helps at work properly again for a short time. Once you figure out which one it is it's an easy replacement at that point for most of them.