Intellivision - suddenly black and white picture and hissing sound - UK Vintage Radio Repair and Restoration Discussion Forum

Okto1984 · 30th Mar 2015, 11:33 pm

This one currently has me puzzled. It worked perfectly for years, then one day I turned it on and had the problems in the title. It hasn't been sat a long time, I used it the week before. Everything else I tested still seems ok, the picture is stable and I can play games like normal. I'm aware the chips controlling audio and sound can break, but chances are they didn't both go at exactly the same time?

So I took it apart and re-soldered the ugly, suspect looking joints connecting the modulator to the circuit board. I also discovered a ribbon cable connecting the power supply to the circuit board was in very poor, crumbling condition, so I removed it and replaced with some regular wires. These were both worth doing, but haven't solved the problems as nothing has changed.

Any ideas or suggestions where to look next would be much appreciated?

jay_oldstuff · 31st Mar 2015, 12:40 am

Very long time since I repaired an intelivision but like all micros and consoles of a certain age first thing to check is electrolytic capacitors. In particular pay attention to ones round the vicinity of the UHF modulator.

Jay

Okto1984 · 31st Mar 2015, 7:18 pm

Hi Jay,
Thank you for your reply. I did swap out all the electrolytic capacitors on the main board, which wasn't hard as there's only four or five little 10uf ones. But nothing has changed.

I also noticed some of the ceramic capacitors have cracks in their cases, so I'm probably headed there next. I'm also going to explore the cartridge connection, as the service manual suggests lack of colour can be caused by dirty or damaged connections to the cartridge.

arjoll · 2nd Apr 2015, 12:14 pm

Does this have an RF connection to your TV? If so, have you double-checked it's tuned in correctly? Being slightly out of tune could do this.

Okto1984 · 2nd Apr 2015, 9:41 pm

Hi arjoll,
It's an RF connection. The problem does look and sound exactly like being slightly out of tune. However, I've tried retuning it on the original set, and using another set, and it has the same problems with both.

SiriusHardware · 3rd Apr 2015, 11:25 am

If the Intellivision has the usual 'tin can' modulator, one of the pins going into it will be carrying composite colour video (the other two will be power and sound, with the 0V supply being picked up by the connection between the metal body of the modulator and its connection to ground).

Try 'jumping' the composite video signal (and ground) straight to a composite video input on a TV or video monitor. Do you get a normal looking (with colour) picture?

jay_oldstuff · 3rd Apr 2015, 1:41 pm

The modulator is a possibility I’ve had a few colour issues with them in the past on spectrum's. The last intelivision I repaired I did a composite video mod on, it was a long time ago but I seem to remember I had to add a transistor to boost the signal slightly.
have you checked the caps inside the modulator?

Jay

Okto1984 · 4th Apr 2015, 8:06 pm

Thank you both for the replies.

I guess replacing the cracked ceramic caps is my next step. I'm not sure why they're cracked, but the general construction quality of this console is unfortunately terrible, so I don't imagine the parts were high quality either.

If that doesn't help, I think a composite conversion is worth trying out. The circuit I found online is pretty simple. It looks like the audio just needs to pass through a single electrolytic capacitor, so I could try that on its own and see if it gives clear audio before attempting anything else more complex with the video signal - although even then it's not massively involved.

Mad Mal · 24th Jul 2016, 5:14 pm

Cracked ceramics was a common fault on some early FM receivers in Hi-Fi separates set ups. More so those of Japanese manufacture. Down to age and heating/cooling cycles. But I'd replace any ageing electrolytics first before homing in on the modulator. If it is the modulator it's probably"dry" joints. Common problem in older transistorised TV tuners as well.

Okto1984 · 25th Jul 2016, 11:45 pm

Hi Mad Mal,
Thank you for your advice. Unfortunately however the intellivision had to go. I wanted to fix it, but had to reconsider that plan. The metal tracks on the PCB were bubbling and going crinkly and cracked across the whole board when I looked closer. It was just too degraded to spend more time on it. Intellivisions aren't particularly rare, although if this wasn't an unlucky example they might be soon... However, I did sell the case on eBay, and to another buyer the controllers (their PCBs weren't bubbling), so it wasn't all a loss. It's good to salvage what you can.

30th Mar 2015, 11:33 pm	#1
Okto1984 Retired Dormant Member Join Date: Dec 2013 Location: Winchester, Hampshire, UK Posts: 288	Intellivision - suddenly black and white picture and hissing sound This one currently has me puzzled. It worked perfectly for years, then one day I turned it on and had the problems in the title. It hasn't been sat a long time, I used it the week before. Everything else I tested still seems ok, the picture is stable and I can play games like normal. I'm aware the chips controlling audio and sound can break, but chances are they didn't both go at exactly the same time? So I took it apart and re-soldered the ugly, suspect looking joints connecting the modulator to the circuit board. I also discovered a ribbon cable connecting the power supply to the circuit board was in very poor, crumbling condition, so I removed it and replaced with some regular wires. These were both worth doing, but haven't solved the problems as nothing has changed. Any ideas or suggestions where to look next would be much appreciated?

31st Mar 2015, 12:40 am	#2
jay_oldstuff Octode Join Date: Jan 2005 Location: Hyde, Greater Manchester, UK. Posts: 1,074	Very long time since I repaired an intelivision but like all micros and consoles of a certain age first thing to check is electrolytic capacitors. In particular pay attention to ones round the vicinity of the UHF modulator. Jay __________________ The light at the end of the tunnel is probably the headlight of an oncoming train

31st Mar 2015, 7:18 pm	#3
Okto1984 Retired Dormant Member Join Date: Dec 2013 Location: Winchester, Hampshire, UK Posts: 288	Re: Intellivision - suddenly black and white picture and hissing sound Hi Jay, Thank you for your reply. I did swap out all the electrolytic capacitors on the main board, which wasn't hard as there's only four or five little 10uf ones. But nothing has changed. I also noticed some of the ceramic capacitors have cracks in their cases, so I'm probably headed there next. I'm also going to explore the cartridge connection, as the service manual suggests lack of colour can be caused by dirty or damaged connections to the cartridge.

2nd Apr 2015, 12:14 pm	#4
arjoll Dekatron Join Date: May 2006 Location: Invercargill, New Zealand Posts: 3,457	Re: Intellivision - suddenly black and white picture and hissing sound Does this have an RF connection to your TV? If so, have you double-checked it's tuned in correctly? Being slightly out of tune could do this.

2nd Apr 2015, 9:41 pm	#5
Okto1984 Retired Dormant Member Join Date: Dec 2013 Location: Winchester, Hampshire, UK Posts: 288	Re: Intellivision - suddenly black and white picture and hissing sound Hi arjoll, It's an RF connection. The problem does look and sound exactly like being slightly out of tune. However, I've tried retuning it on the original set, and using another set, and it has the same problems with both.

3rd Apr 2015, 11:25 am	#6
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,556	Re: Intellivision - suddenly black and white picture and hissing sound If the Intellivision has the usual 'tin can' modulator, one of the pins going into it will be carrying composite colour video (the other two will be power and sound, with the 0V supply being picked up by the connection between the metal body of the modulator and its connection to ground). Try 'jumping' the composite video signal (and ground) straight to a composite video input on a TV or video monitor. Do you get a normal looking (with colour) picture?

3rd Apr 2015, 1:41 pm	#7
jay_oldstuff Octode Join Date: Jan 2005 Location: Hyde, Greater Manchester, UK. Posts: 1,074	Re: Intellivision - suddenly black and white picture and hissing sound The modulator is a possibility I’ve had a few colour issues with them in the past on spectrum's. The last intelivision I repaired I did a composite video mod on, it was a long time ago but I seem to remember I had to add a transistor to boost the signal slightly. have you checked the caps inside the modulator? Jay __________________ The light at the end of the tunnel is probably the headlight of an oncoming train

4th Apr 2015, 8:06 pm	#8
Okto1984 Retired Dormant Member Join Date: Dec 2013 Location: Winchester, Hampshire, UK Posts: 288	Re: Intellivision - suddenly black and white picture and hissing sound Thank you both for the replies. I guess replacing the cracked ceramic caps is my next step. I'm not sure why they're cracked, but the general construction quality of this console is unfortunately terrible, so I don't imagine the parts were high quality either. If that doesn't help, I think a composite conversion is worth trying out. The circuit I found online is pretty simple. It looks like the audio just needs to pass through a single electrolytic capacitor, so I could try that on its own and see if it gives clear audio before attempting anything else more complex with the video signal - although even then it's not massively involved.

24th Jul 2016, 5:14 pm	#9
Mad Mal Tetrode Join Date: Jul 2016 Location: Spennymoor, County Durham, UK. Posts: 69	Re: Intellivision - suddenly black and white picture and hissing sound Cracked ceramics was a common fault on some early FM receivers in Hi-Fi separates set ups. More so those of Japanese manufacture. Down to age and heating/cooling cycles. But I'd replace any ageing electrolytics first before homing in on the modulator. If it is the modulator it's probably"dry" joints. Common problem in older transistorised TV tuners as well.

25th Jul 2016, 11:45 pm	#10
Okto1984 Retired Dormant Member Join Date: Dec 2013 Location: Winchester, Hampshire, UK Posts: 288	Re: Intellivision - suddenly black and white picture and hissing sound Hi Mad Mal, Thank you for your advice. Unfortunately however the intellivision had to go. I wanted to fix it, but had to reconsider that plan. The metal tracks on the PCB were bubbling and going crinkly and cracked across the whole board when I looked closer. It was just too degraded to spend more time on it. Intellivisions aren't particularly rare, although if this wasn't an unlucky example they might be soon... However, I did sell the case on eBay, and to another buyer the controllers (their PCBs weren't bubbling), so it wasn't all a loss. It's good to salvage what you can.