Need help repairing an Intellivision

[Arjak]

So recently, I bought an original model Intellivision off Ebay. When I first received it, it would turn on and read games just fine, but sprite graphics were garbled. I put it aside, thinking I would get it repaired at some point. Recently, I tried it again, and now, it wont boot games at all, and will only display a purple screen for a moment when turned on. After some searching, I found this page: http://intvfunhouse.com/faq/intv_faq7.php

 

So I opened up my system and started doing some checks. Power going from the transformer to the power board connector is correct, but a voltage test of the ribbon cable port revealed that while most of the voltages are correct, the middle hole, instead of showing a reading of +16, is showing around +24.

 

After some examining of the power supply board, I discovered that the capacitors had leaked so badly that they were practically glued to the board. I removed the capacitors, cleaned the goo off with a little acetone, and replaced the capacitors. That didn't fix the problem, so I replaced a resistor (which according to console5.com, can burn out) and the two voltage regulators. Still doesn't work, still has the wrong voltage in the middle hole for the five prong ribbon cable.

 

At this point, I'm completely stumped. I have no idea why only the middle socket for the ribbon cable has the wrong voltage while the rest are fine. I have no idea why the console went from "buggy but functional" to "completely dead."

 

So, I turn to all of you. What should I try next? Is the system even salvageable?

[HunterZero]

The middle pin is unregulated DC, so showing around 24V-26V without load is normal. The 2 large capacitors were typically attached to the power supply board with hot glue to prevent the solder cracking from the weight of these parts, I don't think they would have leaked like that. It sounds like your power supply board is fine.

 

Check that the 2 pin connector with the blue wire is connected properly and has continuity. Check the 5 pin ribbon cable is intact and have continuity, these are notorious for disintegrating.

 

Does the screen flash when you press reset? You didn't happen to have a pic of the garbled graphics?

 

If the ribbon cable is fine, the issue is very likely a logic one. Clean the cartridge port out first with some Deoxit, and try backing out the cartridge a little after you insert it before turning on the power.

 

If that doesn't help you are going to have to open the RF shielding sarcophagus. Try carefully reseating the socketed chips, again cleaning with Deoxit.

 

If there's still no change it sounds like you have a logic issue with one of the ICs, possibly RA-3-9600 RAM, AY-3-8900-1 STIC. Replacement parts are near impossible to find, you would need a donor system to start swapping parts to check.

 

- James

[mr_me]

Yes, and the reading of that unregulated voltage depends on the internal resistence of the multimeter. Could be different with different multimeters. You can connect the logic board and retest under load for comparison.

 

Inspect the logic board closely for problems and clean as necessary. It could be something simple. Cartridge connection could be finnicky as HunterZero suggested and test different cartridges.

[Humblejack]

When you find the problem and if it happens to be either the flat cable or some other small item I have quite an inventory of new replacement parts. This includes chips, cables, and other items. These are all brand new not removed from old units. When you find out what the problem is you can look up the part number. I posted all the lists at INTVFUNHOUSE.com. Let me know and will see if I have one.

 

HJ

[Atari PAC-MAN Fan]

What model is it? Intellivision, Intellivision II, or the INTV 3?

[SiLic0ne t0aD]

Nice! I'd love to by an SRAM chip if there's one available, I could get another broken system back up and running if so.

[HunterZero]

You would need an oscilloscope or logic probe or logic analyzer to deduce logic issues. Having parts available from a 2nd system to swap out is the easiest way to pinpoint a problem IC.

[HunterZero]

When you find the problem and if it happens to be either the flat cable or some other small item I have quite an inventory of new replacement parts. This includes chips, cables, and other items. These are all brand new not removed from old units. When you find out what the problem is you can look up the part number. I posted all the lists at INTVFUNHOUSE.com. Let me know and will see if I have one.

Impressive! How did you come into all these NOS parts? Do you have both variants of the STIC, eg AY-3-8900 CCIR and AY-3-8900-1 NTSC?

[Humblejack]

I looked through but could only find the AY-3-8900-1. I got a whole bunch of stuff on ebay back in 2003. I had all the books, lists, letters and signs along with test carts and a T-cart and all the original repair manuals for a guy in Bismark N.D. I have only sold a few items over the years but think its time to get some out there. As soon as I get a few minutes I will post all the parts I have available.

[Arjak]

Well, I've got some good news! Even though Deoxit didn't fix the problem, I did notice something odd about the cartridge slot. One of the pins was lower than the rest. Using a tiny flathead screwdriver, I carefully bent the pin up to be around the same height as the others. I then did another test, and...

 

 

It worked! In fact, it now works every time! I turned it off, pulled out the cart, put it back in the slot, turned it on again to see if it was a fluke, and tried a different game, and sure enough, the console now reads games every time!

 

Unfortunately, the sprite graphics still seem to be glitched, as seen here. (Isn't that garbled square supposed to be a guy running around the dungeon?)

 

 

Still, this is great progress! If you guys have any ideas of what might be causing the graphical glitches, please let me know!

[SiLic0ne t0aD]

As far as graphic glitches, it appears to be the RAM chip, it says RA-3-9600 on the bottom and has a heatsink on it. When this chip failed on me, I was still able to play certain games but with graphical glitches (the main character, wonky sound with slowdown, etc) and other games didn't really work at all. From your picture above, I'm willing to bet that is the issue.

[mr_me]

Well, the running man graphics would be copied from the cart ROM to the GRAM chips. The gram chips are addressed through the GROM chips. The running man sprite attributes are in the STIC registers. The ra-3-9600 mostly deals with the background graphics but it is also used by the program.

 

More examples of glitches with different games might help. Does the game play, shoots arrows, demons, snakes etc?

[HunterZero]

Yes a few more pics of other games would be useful. If the graphical glitches are restricted to the sprites, it does sound like the STIC is the best place to start, and if that doesn't fix it I would look at the RA-3-9600, then GRAM. A bad RA-3-9600 SRAM can cause all sorts of weird and wonderful crashes and glitches.

 

Make doubly sure that all the cartridge slot connections are clean and solid.

 

Try carefully removing and cleaning the pins of the STIC (and other socketed ICs) and reseating, then if that doesn't help swap the STIC for another.

 

Get some deoxit spray for the cart slot, chip sockets and pins.

 

- J

[Arjak]

Hey guys. I tested my games a few days ago and here's my findings.

 

I only have two games, Utopia and AD&D, but both of them showed the exact same symptom. No pictures, I'm afraid. My camera doesn't deal well with the INTV's screen refresh rate.

 

On both games, everything seemed to work fine from a gameplay standpoint; no crashes or odd behavior. Sound seems right. Background tiles work fine. The only problem I have is that animated or moving objects have garbled graphics.

[mr_me]

If you had a memory cart you could run the diagnostics test cartridge. Does the board look okay visually, no soldering has come loose. Try reseating all the socketed chips as hunterzero suggested.

 

So with Utopia are all the sprites messed up? Both cursors, boats, pirates, fish, clouds. And all the buildings and crops and shorelines are okay?

Edited June 17, 2017 by mr_me

[MMarcoux66]

Having the same problem described with a system I bought off eBay. Tested with just a couple games. They all seem to work but the characters are garbled. I have the whole thing apart and just starting to clean it.

Edited October 18, 2018 by MMarcoux66

[mr_me]

In this case it's not just the sprites that are messed up, some background tiles as well. All custom gram graphics, access to the grom seems okay. In most cases it looks like the 5th,6th,8th pixels of the caracter that's missing. I could guess it's the stic, hard to say.

[MMarcoux66]

In this case it's not just the sprites that are messed up, some background tiles as well. All custom gram graphics, access to the grom seems okay. In most cases it looks like the 5th,6th,8th pixels of the caracter that's missing. I could guess it's the stic, hard to say.

 

I have another Intellivision coming today as well as an INTV III. Not sure of the condition, but hopefully will be able to get one working system from the 3 .

[MMarcoux66]

 

I have another Intellivision coming today as well as an INTV II. Not sure of the condition, but hopefully will be able to get one working system from the 3 .

So, the bundle I got both systems were working. So, I'll have some things to test. The INTV II's controllers were shot. Took them apart and they were a mess inside. Don't think I can salvage them. Looks like I will be rewiring my Flashback controllers this weekend.

[JohnPCAE]

A special Inty program might be able to shed some more light on the issue. Off the top of my head, I can think of some tests it could perform:

 

Note: use white-on-black for all tests.

 

1. Fill GRAM card 0 with 0xFF on each line, all other cards with zeroes, and fill the screen with card 0 to see if screen position is a factor.

 

2. Repeat test #1 six more times using cards 1, 2, 4, 8, 16, and 32 to test the individual card address lines.

 

3. Fill the top 4 scan lines of card 0 with 0xFF and the lower ones with 0. Fill the screen with card 0. I know the problems appear vertically not horizontally; this is to check for cross-wiring.

 

4. Repeat test #3 but fill card 0 with a single diagonal line from upper left to lower right, i.e. 0x80, 0x40, 0x20, 0x10, 8, 4, 2, 1.

 

5.Repeat test #4 but use a diagonal line from upper right to lower left.

 

Use the results of these tests to inform what, if any, tests should follow.

Edited October 19, 2018 by JohnPCAE

[mr_me]

 

I have another Intellivision coming today as well as an INTV III. Not sure of the condition, but hopefully will be able to get one working system from the 3 .

I'm changing my guess to the problem being around one of the gram chips. The stic is able to address and read gram through the grom so that seems to be working. And some of the gram is working since some gram characters are completely correct.

[MMarcoux66]

I'm changing my guess to the problem being around one of the gram chips. The stic is able to address and read gram through the grom so that seems to be working. And some of the gram is working since some gram characters are completely correct.

 

I am going to try to flip the RA-3-9600 from the INTV II with the broken one to see if the problem goes away. If that is the issue, it looks like RA-3-9600 chips are a bit of a challenge to get so I might just punt it on Ebay.

[MMarcoux66]

 

I am going to try to flip the RA-3-9600 from the INTV II with the broken one to see if the problem goes away. If that is the issue, it looks like RA-3-9600 chips are a bit of a challenge to get so I might just punt it on Ebay.

 

Not the RA-3-9600 chip. Same issues on the system with the chip from the II.

[MMarcoux66]

Was not the Stic chip. Put another one in and the same issue. Going to put it back together and get rid of it as I have another working one now.

[mr_me]

The ram chip for gram and even a grom chip shouldn't be hard to find but you'd have to do some soldering. With some testing you might be able to eliminate one of the gram chips as working.