HunterZero

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?

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.

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

And it's suspicious that C11 blew on the PS board, and the unregulated voltage is below what it should be with no load. C11 is part of the unreg 16V supply. I suspect the CPU isn't getting all the voltages it needs through the circuit with the 2 2N3906 transistors Q1 and Q2, and isn't starting. These transistors generate a pulse for the CPU at pins 37 and 38. So the recommendation stands to check the 2200uF cap, and the rectifier diodes CR5 thru 8, and regular caps C9 thru C11 (C11 is nearest the large 10000uF cap). Then move to checking the logic board around Q1 and Q2. That you are getting a black screen indicates the RF circuit is good, and that there is a flash when you press reset indicates that the STIC is probably good too - at least good enough to boot the system. - J

On the main board - Check for voltages at pins 34 (5V), pin 35 (-3V) and pin 36 (12V) of the cpu. If you have a probe, check for clock at pin 15 of the STIC, and that STIC pin 13 is pulsing and has continuity to pin 2 on the CPU1610. We can then check the CPU is actually running. The CPU1610 data lines are on pins 6 to 21.

Yeah the 2 pin supply is unregulated. The STIC datasheet says it takes 5.25V at pin 20 so 5.6V on the schematic is probably correct under load. It's a convoluted power supply setup to be sure. So back to the 16V unreg supply... Did you check the 2200uF 25V cap? What voltage are you getting on the +ve lead of that cap? Worth checking the rectifier diodes CR5 thru 8, and regular caps C9 thru C11 (C11 is nearest the large 10000uF cap). I usually replace the two large electrolytics on the power supply board (and the two regulators) with new ones anyway.

And still concerned that your unreg volts are low - what did the AC from the transformer read?

No obvious issues visually with the board? Scorch marks? No broken small caps? Check the driver transistors near the CPU and electrolytics (although in my experience the SHOEI caps are quality and hold up well). If you have a logic probe or scope you can start checking for clock/data pulses on IC pins. Since you have spares, try resocketing or swapping the CP1610, RA-3-9600 SRAM and PROM/SROM. Check the sockets themselves are good too.

Note the above vid is not mine And when I measure the unreg voltage it measures 23V and doesn't discharge to 0V. Maybe the meter he is using?

100% sure. Mine measures 11.69V across those two pins. Watch from 1:30:

Across the 2 pin connector on the power supply board should be 12V. Apart from the unregulated voltage, everything else looks in spec.

The "16V unregulated" reads about 22-25V without load IIRC. Did you check voltages coming from the transformer? You should get: Yellow Lead to Blue Lead - 18 VAC Green/Yellow lead to any Green - 9.25 VAC Green Lead to Green Lead - 18.5 VAC No flash on reset means the STIC is not working. If you have a spare you could try swapping the STIC.

Have you checked the voltages at the board? Do all the ribbon pins and blue wire have continuity? Is the blue wire with the 2 pin Molex connected properly? Do you get a screen flash when you press reset or nothing at all?

You are going to have to find a 2nd system as a source of spare parts I am afraid, and hope they don't have the same fault, unless someone here has a spare populated logic board that you can use for parts. Opening the RF shield is a pain in the proverbial. It's soldered closed, you will need a soldering iron to get into it. Here is an overview of the Intellivision PCB:

If something works after 40 years, then that's great. But for an Intellivision 1, it seems to be the exception to get a working one rather than the rule. By comparison with other systems from around the same time with lower parts count eg Atari 2600, Famicom/NES, Intys seem to have a much higher failure rate. BITD, my Intellivision failed twice. I've had several master components through my hands, and only one (an Inty System III) worked without any issues whatsoever without some form of repair being needed. Of those, more than half had a failed logic IC that needed replacement. - James

This is why Intellivisions can be problematic - so many ICs, many points of failure... Many of the ICs do not seem to last the test of time.

Deoxit is my non-abrasive contact cleaner of choice. B-17 Bomber will still work without the IntelliVoice module plugged in, you just won't get any voice. I think Intvsteve could be on to something - It could be a logic problem related to the use of the exec system ROMs, either directly, or indirectly via some other system logic. Beauty and the Beast doesn't use the Mattel library code for the startup screen, and being Imagic, I would guess it uses fewer exec functions (more direct to hardware coding to get more speed) and utilises different areas of system RAM. Swapping the PROM and SROM would a logical thing to try. It could also be a logic issue with RA-3-9600 system RAM, or with the AY-3-8914 sound chip (which handles the controllers). You'd need spares on hand to swap these out to test. - James

If you don't want to open the main unit, you can 'disconnect' a controller by opening the handset, and removing the plastic matrix, which disconnects the cable from the matrix.

My copy of Missile Domination arrived today, thanks to Naberhood Games. Must have been about the last copy left anywhere, they're out of stock now! - James

I think that my model 3668 Intellivision modified for PAL-60 is currently one of a kind - unless someone else has done the same mod? It's similar to the Brazil PAL-M Intellivision, except the PAL-60 colour subcarrier is 4.43MHz, unlike PAL-M where the subcarrier is 3.58MHz. - James

The colour circuitry is different. US systems used a single chip solution, most PAL units have a daughterboard that generates the colour. The colour circuitry in my PAL60 unit is the standard PAL circuit. I've seen screen caps of the game running on NTSC and the title screen is black. So the difference doesn't come from the colour circuitry. So I am thinking it must be some code timing issue, as the only variables are the STIC and system clock. Perhaps the game programmer used some 'trick' with the EXEC that is timing sensitive to change the background colour on the title screen, and that trick doesn't work on PAL timed systems? - J

While testing my PAL60 modified Intellivsion console, I plugged in Thunder Castle, and noticed that the title screen background is black when played on a 60Hz system. When the exact same cartridge is played on a 50Hz system, the background of the title screen is the standard olive green. Wondered if someone here could give a technical explanation for why this is so? It must be some sort of timing issue, as the only difference my PAL60 Intellivision has over a standard PAL one is the STIC chip, and the crystal. - J

I have used spray glue. Spray the back of the label and stick it back on. Gives a very thin even coat of glue. - J

The DVD copy really is not the best way to play the game. The moves and timings are not right. However, if you get that DVD set with Dragon's Lair 1 and 2 and Space Ace, you can rip the video to use with the Daphne emulator. That gives a much more faithful result. There was a remastered HD blu ray edition which looks great. But again the gameplay isn't faithful. - James

Great! Glad you got it working! It did sound like a logic issue. I haven't seen that PROM chip go bad before; That chip it is mentioned in the service manual last in the recommended troubleshooting sequence to swap out ICs (CPU, STIC, SRAM, SROM then PROM last!). The system was probably trying to boot (flashing), then crashing/halting. - J