the official Channel F thread!

[+cjherr]

Perfect. Thank you.

[+atari2600land]

Got two new games: Hangman and Alien Invasion. Both were untested, so it was quite a surprise to find they both work great! And both came with manuals. I skimmed the VES manual, and apparently there's no way to turn down the system volume? Both the games I just got are awfully loud. I want the noises, but why so loud?

[e5frog]

You can set two different types of sound effects on Hangman - or set it to mute. For Alien Invasion... I guess you need a pillow over the speaker or something.

Quote from instructions:
"

SOUNDS

While playing a game, the computer sounds can be
changed by pressing button 2, 3, or 4 (pressing button
1 changes game options).

Button 4 - normal sound
Button 3 - alternate sound
Button 2 - no sound

You may change sounds as many times during a game
as you like.


You´ll get the hang of it in no time!

"

[Atari2008]

Got two new games: Hangman and Alien Invasion. Both were untested, so it was quite a surprise to find they both work great! And both came with manuals. I skimmed the VES manual, and apparently there's no way to turn down the system volume? Both the games I just got are awfully loud. I want the noises, but why so loud?

With Alien Invasion you can turn it down on the console by pressing 3. I agree though the system is really loud. I wish they had included a sound off/on switch like the RCA Studio II or at least a way to adjust the volume. I avoid playing it at night since it's so loud.

[+atari2600land]

Example cartridge #2 on eBay right now. 6 days until the end of the auction. How high will it go?

Auction #143297642120

[+atari2600land]

The answer: $1,462. Someone paid $1,462 for a democart #2 and three dirt common games. Is a Democart #2 worth that much?!

 

[Atari_Bill]

2 minutes ago, atari2600land said:

The answer: $1,462. Someone paid $1,462 for a democart #2 and three dirt common games. Is a Democart #2 worth that much?!

 

I don’t think so. Not even close but apparently it is to someone that has money to burn. I was questioning some of bids midway through with zero feedback. Looked suspicious to me, but the final 2 bids for the big money both look like legitimate bidders. 

[e5frog]

F*
Spent 10 minutes writing a wrong reply and site stopped working - post lost. 

I'll try and make it shorter.

I was first looser, at $1437 - and no, I don't think it's worth that much, I hoped nobody else would be that "generous". The $650 I had managed to save up for it would have been a more sane price when comparing to the Democart 2:s that have been sold on eBay before.
As I gathered funds I continuously raised my bids and put in the huge one when I was able to fund it (with extra, borrowed money). Of course now there was a bunch of bids just by me so I decided to clean up, retract the bid(s) and put it back in again...

Jumping to the end I checked sniper sites (suggested by Shane, the seller) but decided to snipe manually (the thrill, the thrill) and I managed to time it with five seconds to go, the winner was a second earlier - but the biggest wallet always wins anyway, you snipe to not reveal your top bid and hopefully bid so late that others don't have the time to reply with a bid. I think the $25 he beat me with is the minimum bid increment at that level.

I wish I had decided to just snipe to start with as my (initial) top bid was revealed by an account with 1 in feedback, 10 bid retractions and also bid 36 times in 15minutes, low balling with bids like $399.99 and similar - trying NOT to win. Then stopped as maximum was revealed - $2 from the max bid. I believe it was $1327 (yes, it's in the listing). Complained to the seller, as well as eBay, seller cancelled the bids and blocked the bidder, eBay sent a standard message pre-formulated message (pretending they don't earn big box from shill bidding) saying they will take actions that I would notice but not what. That shill bidder account is still active, now has a bunch of more bids and now 16 bid retractions, could be an automated service even that people paid for, you just need to register with an email address to get an account, that's it. 
https://offer.ebay.com/ws/eBayISAPI.dll?ViewBidderProfile&mode=1&item=143297642120&bidtid=1669322691004&_trksid=p2471758.m4792

You can't dodge it when people are messing with you (an auction) on eBay, not if running a plain auction. 
 

Now I was in the lead again - at $310.
The information about my top bid was already found out though. So, I retracted my bid again - what to do, can't just continue to raise, it was already a ridiculous amount of money.
Just to safe up in case auction would end at $305 I put a bid in at $306 and decided to leave it, it was already a tainted auction and you never know if it's outside interference, if other odd things will happen and/or if the seller is involved. 
When a 0 feedback bidder suddenly popped up I bid a little more, but managed to "help myself". There was some real bids and then another 0 feedback bidder!? 

Couldn't resist the temptation with Shane's tip, and then you know the end, had to add some so it got $110 higher - but it wasn't enough. 

So it kind of sucks but I'm still kind of happy I didn't actually win it for that much, have my $650 left and didn't have to borrow any money. 
The obfuscated bidder alias and feedback score looks familiar, should be a known collector I think.

 

Who knows how it would have ended without the 0/1 feedback bids, I guess I would have bid $1327 and the other guy would have gotten it for $110 less.  

If it was a fake win or the real winner changes his mind/non paying bidder - we'll see that Democart 2 again, by itself - at a much higher price than the $75 this lot started on.
Mhm - you can prevent a sale by a fake bidding winner that doesn't pay - no fees. Then, when feeling the waters you can squeeze out a little more. Not that I think it was a fake winner with that feedback score (1228). 

High bids like this will also attract people to the system, as well as general brokers buying and selling anything - and we'll be forced to pay a lot more than if it was deals between flea market finds and collectors. 

 

Edited July 1, 2019 by e5frog

[e5frog]

... and it was five dirt common videocarts - like new presumably, which would have been a nice swap/upgrade in the collection.  

Edited July 1, 2019 by e5frog

[Atari_Bill]

That stinks. I thought those bids seemed very suspicious.  Something was up with someone bidding on this auction. 

[Blazing Lazers]

Glad that I'm not the only one who thought that something was really off about this recent listing. To my immense surprise, I was the high bidder... TWICE. And still didn't win.

 

When I first noticed the listing it was already over $400 with several days to go, but I still put a bid in. I was automatically outbid by whatever the max bid was  at the time. I probably wasn't going to do a manual snipe, as I don't consider D2 to be part of the full set. It is something contemporary, but unlike D1 (which does count toward the full set) it was never made publicly available. Nobody could have bought it back in the day.

 

So, I wasn't too upset about this possibly passing me by. I already have the full set CIB plus homebrews, I don't need this one. Plus, there's been a fair amount of copies turning up in recent years, including a real boxed one a year or two ago. There's about 6 or 7 copies floating around.

 

A day later I recieved an email from Ebay notifying me that I was outbid-again. Apparently, at least one other bidder had their high bid cancelled. At the time I hoped that schoolgirl or happiest had been speculating and that somebody had alerted the seller and got them removed from contention. Then I got the same email the next day saying that once again I was outbid. Bids by somebody else had yet again been cancelled.

 

I've never had this happen before on an auction, so now I was really leery of any further. I had a bad feeling about this listing.

 

As much as I hate to say it, this cart could be a fake. The cart label scans are readily available online, and all it takes is a blank white box and a regular cart shell to complete a very accurate replica. I know, because I did so myself a while back when an undeniably genuine boxed D2 sold on Ebay to a worthy collector. It was the first time a box had turned up for this title.

 

The backstory as provided by the seller seems plausible, but somehow strikes me as iffy. Everything that had previously been known (to my knowledge) had D2 as being a salesmans tool, possibly only for international sales and demos. More than one of the first found copies were supposedly found outside the US. It also doesn't seem too likely to me that the very least common vintage cart would only be found along with the absolute most common titles, and only some time after a known genuine boxed copy had surfaced.

 

I do hope the other Channel F collectors will chime in, and reassure us all that nothing was really amiss with this listing and that all's well and there are now at least two surviving boxed Democart 2s. In the past I haven't been concerned with fakes for pre-Atari systems, but D2 would be an extremely easy one to fake, especially if it is listed as "untested" and dead Channel F carts are a known thing.

[e5frog]

Speaking for being a real copy is the included other carts that look very new (supporting the story) but it would have been wise to ask to see the edge label and PCB before bidding. 
That as well as having a high feedback and the guy selling old used vinyl records and could very well have stumbled upon this. 

The PCB with its chips would be quite difficult to fake.

[ubersaurus]

On 4/15/2019 at 5:47 PM, e5frog said:

Well, that's true, getting new chips often requires a second unit - not having damage on the same chips.

 

Electrolytic caps have different quality and lifespan, so get the best ones you can get and it should be OK, hopefully. As the sizes are a lot smaller nowadays you can go up one or two steps in voltage to get them a little closer to the old ones in size.

Avoid odd, cheap Chinese "brands" imitating the names of good brands. Why not go for the "first tier" caps here:
https://www.tomshardware.com/reviews/power-supplies-101,4193-5.html
Good brand names do have lower quality caps as well, sorting for price is usually a good indicator. I tend to get Panasonic myself mostly - as that's what my supplier usually has in stock.

 

Waves could indicate a voltage-problem, so in this case I'd probably start off and replace regulator(s) and caps.

Hoping to crack this CF version 1 open this weekend - anything I should know before I do so about getting through the RF shield, or removing the five buttons on the console itself? If it's having voltage issues I figure I should get it sorted sooner than later.

[e5frog]

Simply pull buttons straight up, you may have springs under them. Either you have metal case with clamps on the edges, just pull loose, or you have a whole lot of screws... 

Tricky part is actually the cart holder which needs to be removed before getting in there. Four screws that may have washers (which you don't want to drop when remounting). Then the two white ribbon cables. 

These are actually pushed into the cart connector as well as the connector on the motherboard. 

Will get some images... 

[e5frog]

Naah... pulling ribbon cables from the motherboard connectors is easier I think, mounting them again is a bit of work, which is why I wanted to check how hard it was in the other end. 
Ribbon cable is bent twice to fit through a slot at the cart connector end... and you basically have to flatten it to get it out through the slot of the connector if you don't want to unhook it from the motherboard- so - no go. 

I think the American model (like SABA Videoplay) has a connector with isolated pins through the metal case, just pull those, pretty sure it's keyed so you don't put it back the wrong way. With it's loose you can put the entire PSU aside.

After pulling the cartridge ribbon cables (in backwards direction) with the cartridge connector assembly you need to unhook the RF cable before you can pull the top off. It's peeled clean with the braided shield showing and a clamp to the metal case, slide clamp loose (difficult usually) and then pull the RCA looking antenna cable from the motherboard. As you may notice they thought it was too much work to drill a hole in the motherboard under the connector to fit a normal RCA connector - so this one has the pin cut down, which you need to replicate if you want to fit a better cable in there later on.

Power is loose, RF cable loose, chute loose... just pull off, right? Nope, open carefully and you have a connection internally from those four pins in the metal case to pins on the motherboard (perhaps soldered), loosen that and you can put the metal top aside. If you want to test later on you need to bridge the internal connector and the PSU connector, I have used bent pieces of solder tin, worked fine. 
To be able to work on the board (solder on the solder side) you now have to de-solder (preferably) the braids grounding the motherboard to the metal shell, it will be difficult if you don't have a soldering iron with enough oumhpf (I believe that's the technical term). Both regarding wattage as well as type of tip (large tip usually has the best heat transfer ability). You could snip them in half and it may be a little easier to solder them together again. 
Now you need to unscrew the regulator heat sinks from the bottom metal case, old boards have a 7812 regulator for 12V in a TO-220 capsule, not heat sinked and a 7805 regulator in TO-3 capsule that is screwed to the bottom metal case with an angled aluminum piece. If you have the "Channel F 1.5" with a lot of empty space and no rows of logic circuits as well as the smaller PSU you'll just have a TO-220 of both 7805 and 7812. That ones has the same electronics as the Channel F II but on a big board and often also a build in speaker but sometimes sound on TV. 

After that, motherboard is loose, check how the controller cables are drawn if you plan on reassembling, usually bent in an angle with paper tape around them. You may also have this version, which seems a bit overworked:



Final problem is the speaker, foam that was there is likely a brittle, cloggy, sticky mess and the speaker will hang in the wires. Mark a cable and the connector on the motherboard so you'll reattach + and - in the right spots. It helps a lot to remove it instead of having to tape it down or leave it hanging in its wires. 

Be careful not to have any little metal stuff under the motherboard if you hook it up while on the laboratory bench/kitchen table/floor/grass/bed...  it's pretty sturdy stuff though. 

I can recommend cleaning at least the contact surface of all socked chips. The four RAM chips may be gold plated which means the sockets are the ones getting oxidized. Mark positions and type


The metal ribbons in the ribbon cable is prone to come loose from the plastic sheets, a piece of thin double sided tape (or the type that is just glue with no plastic tape) may help, you can wipe the glue off in between the metal parts with proper solvent (depends on the glue on the tape). If you don't have anything like that you can side it over the edge of the plastic in an angle so that the metal parts will meet with the metal of the connector first and the the plastic. Now at an angle, metal parts already touching, you can firmly press the ribbon cable into the connector. You need to do this with the cart chute loose on top of the top metal cover with the ribbon cables going through the slots. You may however want to test things before closing it up. 
Makes you wonder if they had other plans for the cart chute - apart from a mechanical point of view having less stress with ribbon cables moving - why the long ribbon cables?

 

Worst possible scenario if having taken the ribbon cable from the cartridge connector assembly.
You see the angled shape of the cable end:


Here's sliding the ribbon cable into the slot of the cartridge connector assembly:

The connecting slot is then here (here removed from the former slot):

 

If you give up there are options, I suggest (instead of like in the image) you use double the amount of wires and ground every second (unused) wire.

I use this one for my Sean Riddle Videocart dumper. 

[ubersaurus]

Thanks for the photos and the explanation - it's very informative! Much appreciated.

[Mikebloke]

Shame about the democart bids. I am extremely nervous these days about bidding anywhere before the end on anything rare, though I assure you I will never be bidding that much on a cart like that so I'll never be in competition! The democarts is an interesting item and would love them, but I'm not prepared to pay the price of an entire complete commercial collection for it. 

Edited July 9, 2019 by Mikebloke

[HoshiChiri]

On ‎7‎/‎5‎/‎2019 at 12:58 PM, e5frog said:

Simply pull buttons straight up, you may have springs under them. Either you have metal case with clamps on the edges, just pull loose, or you have a whole lot of screws... 

Tricky part is actually the cart holder which needs to be removed before getting in there. Four screws that may have washers (which you don't want to drop when remounting). Then the two white ribbon cables. 

These are actually pushed into the cart connector as well as the connector on the motherboard. 

Will get some images... 

And chance of getting button pictures? My button 2 no longer works- it feels like the spring is broken/gone. I'd love to have an idea of what's needed to fix it.

[e5frog]

There seems to be two versions of buttons, one uses external coil springs, the other has gold plated internal springs that also works as the connecting piece in the switching part. Buttons are pretty much sealed up, you can try anti oxidizer in the plunger gap - or drill a small hole, I did that once. I once cut the top part off and rolled out a little piece of the spring so I'd get a fresh piece pressing against the metal, it had worn down and anti oxidizer didn't help.

If it's the external spring version you can steal one from another keyboard perhaps. I imagine, worst case, cut one of the other springs in half and pull them long enough.

Haven't got any images right now, can post some tomorrow.

[e5frog]

Buttons without external spring, had one taken apart. 

 

BTW, got my order with composite mod PCB:s, will give it a try soon. 

[tnt23]

Greetings all, what a relief it is to find a topic on Channel F, and even more joy to discover it is live

 

I've been fixing a first generation unit for a friend recently, replaced an electrolyte or two and got composite video out. The picture I got had quite a bit of ghosting, and colors were clearly not looking right.

 

My friend then hacked a video test binary for me to ease the debugging. The test displays white vertical stripes one pixel wide on black background, or R, G, B stripes on white background, and toggles between them with any button. From what I see, and judging on some oscilloscope shots I took, looks like chrominance sneaks too much into luminance, effectively making single pixel line into three or four colored ones. I will try to separate the two to see if this is the case, until then if somebody has any ideas please chime in.

[e5frog]

I have noticed the NTSC version is a lot worse than PAL... or mine has a similar problem - or the mod isn't a good one for the first version. Did you have a good level on the chroma amplitude? Maybe signal is too strong and it saturates. 

In my first mod attempts I separated the luma part and added the chroma in after. It's possible a separate amplifier would help. 

 

Other than that I'd try piggybacking some of the involved IC:s and see what happens. I used that method once to fix weak blue color. 

I've also come across bad disc capacitors in 70's electronics. Perhaps something to desolder one leg on and measure?

I guess some noise is to be expected with these things. 

[tnt23]

Thanks for your input e5frog. Since I haven't separated chroma yet, I cannot tell if its amplitude is OK. I have played a bit with chroma outputs, shorting them to ground with 0.47 cap. Disabling BURST turned the whole display black and white, however ghosts were still there. Then I have shorted CHROMA the same way, and ghosts were gone.
I'll post some scope shots later.

 

Checking ceramic caps sounds like a good idea. For the output, I have hacked a quick video mod using THS7316. Trimmed its input level so that output is around 1Vpp, display appears a bit dim but that's OK for the time being.

 

It would be handy to have a PCB drawing showing at least components positions. Most caps and passives have their references printed on the PCB right under them.

[e5frog]

Ghosting is often an impedance mismatch... if it's RF at least. 

 

When checking a Luxor v1 I was servicing today I took a few images. I get rather sharp edges over RF but everything that is just 1 pixel wide gets a rolling checkered pattern.

I notice there is some ghosting as well as if there's a pale version one pixelrow to the right.

 

I'm going to solder a composite video PCB shown above and see if I get any significant difference.

If the chroma is lowered this pale version will be hidden but t's not really a solution to the problem.

Perhaps the chroma resolution is lower than the luma resolution?

 

What else could it be... slow circuits, signal bouncing, speed of VRAM? 

 

[e5frog]

First soldered version. 
Had to buy a couple of other components than planned due to not selecting a large and expensive company... 
So 4.7µF instead of 1µF on the video input (not sure about that one), 22µF on the audio (which is fine but it barely fit the footprint), sandwich of two 150 Ohm resistors (parallel) instead of a 75 Ohm and I used a potentiometer I already had.