Technical help to powerup original keyboard component in UK

[decle]

Thanks everyone for your help so far.

 

Looks like I might need to learn some basic electronics testing on circuit boards (unless when I open the unit up something is obvious).

I'm liking this "can do" attitude.

 

Been watching some YouTube clips on testing circuit boards with a logic analyzer, daft question - how do I avoid zapping myself bad as I take it the unit and board need to be powered up ?

Unless you are opening up a CRT you will be fine working on retro hardware. In both the Master Component and the Keyboard Component the high voltage stuff is contained on a specific board (circled in red):

 

 

 

(Sorry can't seem to find better images of the inside of the keyboard component. y-bot uploaded some good ones a while back but they seem to have fallen victim of the photobucket purge).

 

Don't touch these, any transformers or mains switches while the power is on or for 15-20mins after it has been turned off (electrolytic capacitors store a reasonable charge and whether or not this is retained depends on the circuit design, better to be safe than sorry) and you are safe. Everything else, typically the green PCBs, is 12V and less, no danger to life of limb. A slightly larger concern is that accidentally shorting things as you go probing the board might damage something. However, my experience is that most electronics are very robust, and things have to get pretty hot as a consequence of a prolonged short to cause a problem. With the Logic knock off I use, I tend to set up the probes with the machine turned off to prevent shorts as I add them, then fire it up and kick off the data capture on the laptop.

 

If it would help I'm happy to arrange to drop by, I can bring along some test equipment and show you the ropes. I also have a US Sears Super Video Arcade that might serve as a spare master component in the unlikely event that your primary has a problem. Drop me a PM if this is of interest.

 

Strange that no keyboard commands are recognised except moving the monitor to game mode , 'C" "Return", cannot even get cassette deck to eject. Maybe if the kb video chips fails it doesn't let you do much else with unit.

I don't think this is so strange. If you look at the list of commands available to you (Tape, Cartridge, Index, Resume, Eject, Clean and Screen) only "C"artridge does not require either the tape deck or keyboard screen subsystem to be operational. The good news is the "C" does require pretty much everything else to work.

 

It looks as though the lack of sound is probably down to the use of a flat screen TV, and there are ways of fixing that with an AV mod to the Master Component.

 

The tape deck is electro-mechanical. Even if it was not known to be very fragile, it has moving parts, solenoids, relays, belts, etc that will wear, perish and sieze. It is a matter of taking the mechanism apart, working out what can be persuaded back into life with some appropriate lubricant and what needs to be replaced. That said, if things have died, finding replacements for anything other than belts is likely to be hard bacause they have to fit mechanically as well as electrically.

 

Where would one get so ancient chips if needed ? Especially the video chip which is probably a certain model for the unit.

As mr_me said, eBay is your friend. But to be honest, it's not worth worrying about that yet. The problem (if there is one, it might just need some adjustment of a potentiometer somewhere) is more likely to be a blown electrolytic capacitor or a dry joint.

 

 

Cheers

 

decle

 

[+Lathe26]

... I tend to set up the probes with the machine turned off to prevent shorts as I add them, then fire it up and kick off the data capture on the laptop.

 

I'll second this. I once fried a board (not Intellivision related) while adding probes to a powered board. Luckily, I only burnt out a replacable chip.

[Ron The Cat]

The knowledge people have on this forum is amazing , have dropped decle a PM to book a home visit for the "patient"

[HunterZero]

Wow great find, even if it's not working it's a museum piece!

 

There is no HV in the master component power supply board with the blue caps. That power board takes the 9V/18V AC input from the transformer output, and generates the DC voltages needed by the main logic board, it's just filter caps, regulators and rectifiers.

 

Not sure about the power board within the Keyboard Component?

[decle]

 

First up, I'd like to thank RonTheCat for his very kind hospitality (if you are in London and get the chance, ask him for the address of his favourite Italian, you will not regret it) and for inviting me to poke about with his Keyboard Component. Living in the UK, I genuinely thought I would never get to see one in the flesh, let alone have the opportunity to tinker with one.

 

Secondly, although I took some pictures, in hindsight I probably did not take enough, and my phone camera is rubbish. So, apologies for that.

 

From the outset the machine was desperately close to working. It did not really come out in the earlier pictures, but on the main logo screen there is a line of white dots at the top the screen. Going to free-form text mode these vanish and you are left with a blank green screen. However, typing some characters results in vertical streaks, the right hand one being brighter than the others. Presumably the cursor.

 

The machine itself, serial number 2081, is in excellent physical condition. No significant scratches or dings. The glue holding the gold stripe above the keyboard is failing, however, this would be easy enough to repair. Opening up the machine it is also very clean inside. No evidence of scorching, or bulging capacitors. Very little in the way of fluff etc.

 

In opening the machine up, care must be taken with the three thin splines that extend from the lower case either side of the 6502 cartridge ports. These are quite tall and look pretty flimsy. Be sure to initially lift the two halves apart vertically, until you are sure you have cleared the splines. Having passed the Intellivision cartridge through the upper case it is possible to rotate the keyboard and lay the whole upper case face down along the front edge of the unit, without disconnecting any cables.

 

Initially, we confirmed the PSU output at the test points on the power board just behind the logic board connection. At 5.15V, 11.99V and -4.86V these were close to nominal. The 5V line was adjusted down to 5.0V in accordance with the service manual guidelines. Although there was another pot on the power board it was not amenable to movement, so the 12V and -5V lines were left as found.

 

 

Extracting the motherboard is a matter of undoing the retaining screws (4 of which have red washers), undoing the power, keyboard and cassette board connectors. All are simple pin headers that pull off. Like US Intellivisions the KC motherboard is completely enclosed in an RF shield. The two halves have to be slowly and carefully desoldered and pried apart. This is a pain, not helped by the fact that I forgot to bring a solder sucker. That said, with two people working on it, it proved doable.

 

 

The board inside is a Computer III, presumably the standard consumer model. I could see no evidence of production patches or changes. No scorching or any problems.

 

With the foresight of Nostradamus, RonTheCat had obtained a replacement CRT5037 video chip (pin compatible second source for the canonical TMS9927). We decided to give it a punt and replace it. This fixed up the video:

 

 

I could not get the original heatsink off the dead TMS9927. So we went with a small modern heatsink attached with thermal tape.

 

If anyone has ideas about separating Intellivision heatsinks from ICs, please let me know. It would be good to revert to the original if possible.

 

In putting the motherboard back into the case we omitted the component half of the shield for the moment. This should improve cooling to the board and make it easier for Ron to do further maintenance, should it be required. Again it can be reverted to stock in future.

 

The video output was seen to be stable over multiple restarts and for about an hour of continuous operation. The picture has quite a bit of noise on it. However, this seems to be consistent with that seen with the MC on its own, and my US Sears unit. Therefore, like the lack of sound, for the moment this is believed to be a “feature” of using a US machine with a modern UK flat screen TV. Both problems might be fixed with an AV mod, providing such a change is compatible with the KC video overlay mechanism. Some investigation is required here.

 

At this point all keys on the keyboard were tested in the full screen editor and found to be working.

 

Moving on to the cassette drive. The eject mechanism did not work. Applying the documented credit card trick it popped open. Tricking the KC into thinking a tape had been inserted by depressing the microswitch at the back left of the tape drive (when viewed with the KC the correct way up) it was possible to issue the “TAPE” command. This resulted in the main drive motor spinning. However, the tape spindles did not turn, and the tape mechanism also did not move onto the heads. I’m guessing the tape heads and capstan movement is also motorised in the absence of the normal mechanical play mechanism. Closer inspection of the area around the spindles revealed what looks like degraded belt residue.

 

 

Does anyone know the specs of a suitable replacement belt?

 

Are any special precautions required in cleaning and fitting a replacement?

 

Removing the tape mechanism is a matter of taking the plastic tape door cover off the outside, this secured to the metal tape holder by 2 screws on either side, visible when the tape door is open. The drive itself can then be removed from the reverse side by removing 4 screws.

 

 

The tape opening mechanism is operated by a solenoid, protected by a diode (left, below). Although I did not have an oscilloscope, a small blip in the voltage across the solenoid could be seen when the eject command is issued using a voltmeter. Therefore, I suspect the driver circuit may be working. The solenoid armature and door mechanism were relatively free to move. The solenoid did report a small resistance, but attempting to trigger it manually with a 9V battery failed. Presumably it requires 12V.

 

 

Does anyone know the voltage that should trigger the solenoid?

 

I’m not sure at what point the heads should be brought into contact with to the tape. So I don’t know whether that aspect of the drive is working. Clearly, there is the potential for much more investigation of this.

 

 

Overall, I think the day was pretty successful.

 

 

Although as always there is always more that could be done:

• Replace CRT5037 heatsink with authentic part
• Replace component side RF shield and tidy solder joints
• Reattach gold strip above keyboard
• Investigate tape drive solenoid
• Clean and replace tape drive belts
• Investigate AV mod in MC to tidy up video output and sort out sound
• Investigate the behaviour of the tape drive further

 

So, once again. Thank you so much to Ron for a wonderful day, and for letting me play with his very special toy. It is very rare to share an Intellivision “play day” in the UK, and the opportunity is much appreciated.

 

 

Cheers guys

 

decle

 

[+Lathe26]

Thanks for sharing the work, the debugging steps, and the photos.

[+cmart604]

Cool, nice you guys were able to do this. Thanks for sharing this tale of discovery. If you ever come to Vancouver...

[+JasonlikesINTV]

Thanks for documenting the experience! I was hoping to see some pics of delicious Italian food, though

[Ron The Cat]

Thanks to Decle's home visit the patient is doing well and far from being just a "brick" as my other half described it when it turned up.

 

Was so interesting to get a crash course on how some of the electronics work and are tested and have it so well explained.

I was lucky to purchase the KC for just under £1k "as is" so expected it would be just a museum piece. Canadian squirrels had chewed at one side of the box as it had been in the garage for 30 years untouched.

 

Can't thank Decle enough for bringing it back to life - will always be welcome down this neck of the woods with an Italian meal thrown in at my local of course.

Owning an Intellivision was not such a common thing in the UK so it was nice to chat about stuff in person for once.

 

I would like to thank everyone who chipped in on this thread with advice. Looking back if anyone has to do this in future its well worth just getting all the relevant chips ordered before hand (especially the CRT one) so at least you have them to hand if needed.

Must admit that I did not even imagine they would be available and relatively cheap when I started looking.

 

The KC is serial # 002081 so produced in the middle of the 4000 production run

Edited December 3, 2017 by Ron The Cat

[Ron The Cat]

Thanks for documenting the experience! I was hoping to see some pics of delicious Italian food, though

Here you go ...a pic of pasta with muscles and prawns from their web site , Café Amisha in Grange Road SE1

 

They do a mean martini with olives as well

[Intymike]

Many of the old tape systems have the rubber belt problem. They vanish over the years. Clean the rolls from the residue and put a ne belt on it and you should have a working tape drive.

 

My experience with the A/V modded NTSC console is the following: I can use my Intellivision II with a simple A/V mod with my System Changer. The video signal of the System Changer gets through. I cannot use the System Changer with a RGB modded Intellivision II.

[mr_me]

...

 

Moving on to the cassette drive. The eject mechanism did not work. Applying the documented credit card trick it popped open. Tricking the KC into thinking a tape had been inserted by depressing the microswitch at the back left of the tape drive (when viewed with the KC the correct way up) it was possible to issue the TAPE command. This resulted in the main drive motor spinning. However, the tape spindles did not turn, and the tape mechanism also did not move onto the heads. Im guessing the tape heads and capstan movement is also motorised in the absence of the normal mechanical play mechanism. Closer inspection of the area around the spindles revealed what looks like degraded belt residue.

 

kcTape3.jpg

 

Does anyone know the specs of a suitable replacement belt?

 

Are any special precautions required in cleaning and fitting a replacement?

 

Removing the tape mechanism is a matter of taking the plastic tape door cover off the outside, this secured to the metal tape holder by 2 screws on either side, visible when the tape door is open. The drive itself can then be removed from the reverse side by removing 4 screws.

 

kcTape1.jpg

 

The tape opening mechanism is operated by a solenoid, protected by a diode (left, below). Although I did not have an oscilloscope, a small blip in the voltage across the solenoid could be seen when the eject command is issued using a voltmeter. Therefore, I suspect the driver circuit may be working. The solenoid armature and door mechanism were relatively free to move. The solenoid did report a small resistance, but attempting to trigger it manually with a 9V battery failed. Presumably it requires 12V.

 

kcTape2.jpg

 

Does anyone know the voltage that should trigger the solenoid?

 

Im not sure at what point the heads should be brought into contact with to the tape. So I dont know whether that aspect of the drive is working. Clearly, there is the potential for much more investigation of this.

 

kcGuts.jpg

...

I think the tape command starts with a tape rewind, so the pinch roller and tape head shouldn't move. The "clean" command works with no tape in the drive, moves the head, moves the pinch roller to the capstan, and the capstan spins. You can see it in this video. https://m.youtube.com/watch?v=HWp-wPnshQE

 

You can see a photo of the tape drive belt here. http://atariage.com/forums/topic/264995-intellivision-keyboard-component-cassette-deck/?p=3752376

 

Nice work guys!

[scalpel]

Great job ! Impressive and nice to see

[mr_me]

...

 

With the foresight of Nostradamus, RonTheCat had obtained a replacement CRT5037 video chip (pin compatible second source for the canonical TMS9927). We decided to give it a punt and replace it. This fixed up the video:

 

kcScreen.jpg

 

I could not get the original heatsink off the dead TMS9927. So we went with a small modern heatsink attached with thermal tape.

 

If anyone has ideas about separating Intellivision heatsinks from ICs, please let me know. It would be good to revert to the original if possible.

 

...

In this post they used a heatgun to remove the heatsink. http://atariage.com/forums/topic/207327-made-some-progress-on-keyboard-component-repair-questions/?p=2678306

[m-crew]

????

Thanks for sharing this with us here ,very interesting and learning experience for me.

 

Cheers

[mthompson]

Really interesting info and photos. I hope you're able to get the tape drive refurbished and working. And then get your hands on some software.

 

Do we know if the keyboard component is compatible with other flavors of the Inty I (Sears, Tandy, Sylvania) as well as the Intv Corp. consoles? Certainly the form factor works, but are there chip variations that would make these incompatible?

[mr_me]

The Sylvania, Sears, Tandy Intellivision were made alongside Mattel's Intellivisions. Once you take the cover off you wouldn't be able to tell the difference from Mattel's. Sylvanias would be early, made in usa versions and Tandy would be the 1982 made in hong kong versions. Sears have a different exec chip but that shouldn't affect compatibility.

Edited December 7, 2017 by mr_me

[Walter Ives]

On 11/19/2017 at 11:54 AM, decle said:

Don't touch these, any transformers or mains switches while the power is on or for 15-20mins after it has been turned off (electrolytic capacitors store a reasonable charge and whether or not this is retained depends on the circuit design, better to be safe than sorry) and you are safe.

The power supply capacitors are only charged to the transformer output voltage (maybe 18 volts for the 12V supply, 10 volts for the 5V supply) and bleed off through the voltage regulators in a few hundreds of milliseconds.