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Dirk
February 14th, 2009, 08:32 PM
Hello to all,

I am new to this site. I could use a little help. I just scored a Commodore Vic-20 with the following software:

“Start Programming with Gortek and the Microchips” includes 16k memory expansion cartridge & cassettes
“VIC Typewriter Word Processor with Typing Tutor” on cassette
“Paratrooper by Nic Dudzik” on cassette
“Personal Finance 1” on cassette
“An Introduction to Basic: Part 1” on cassette
“Expense Calendar (Part 1)” on cassette
“Typing Tutor for the Vic20” on cassette
“Personal Finance II” on cassette
“Adventure Pack II” on cassette
“Home Inventory” on cassette
“Loan Mortgage Calculator” on cassette
“River Rescue” game cartridge
“Choplifter” game cartridge
“Shamus” game cartridge
“Apple Panic” game cartridge
“Cosmic Cruncher” game cartridge
“SUPERSMASH” game cartridge
“Tooth Invaders” game cartridge
“Pirate Cove” game cartridge
“Gorf” game cartridge
“The Count” game cartridge
“Radar Ratrace” game cartridge
“Omega Race” game cartridge
“Adventure Land” game cartridge
“Clowns” game cartridge

The Vic-20 did not come with the cassette player, any kind of monitor or joystick. In appearance the Vic-20 itself looks nearly new. The plastic is not discolored at all. It even has the original keyboard cover in mint shape.

I spent about well over an hour trying to get a picture on my cable ready TV without luck. The LED illuminates on the Vic-20 but no picture. I am trying to go in through a TV input port on my VCR not sure if that should matter. The instructions say to connect the RF modulator box to the 2 VHF antenna leads on the back of the TV. I don’t have the proper connector to go directly into the back of the cable ready TV. I have tried channels 3 & 4. I have also tried changing the switch setting on the RF modulator box to both channel 3 and channel 4 as well. No luck.

Any insight or direction you might have would be appreciated.


Dirk

patscc
February 14th, 2009, 08:41 PM
If you've got the twin leads from the modulator, they are called 300 Ohm balanced. If on your TV you've got the round one with the pin in the center, that's called 75 Ohm unbalanced. To go between the two, you need what's (I think, unless my memory is off) called a balun, and RatShack should have them.
Here's the pinout in case you want to go from the VIC directly to a monitor:
http://pinouts.ru/Video/Vic20Video_pinout.shtml

On your VCR, you're using the 300 Ohm balanced VHF antenna input, correct ?
patscc

vwestlife
February 14th, 2009, 08:44 PM
The VIC-20's RF modulator puts out a TV signal on channel 3 or 4, not a composite video output, even though the connector is the same. You need a switchbox or an "RCA to F connector" adapter to connect it to your TV's antenna input.

The RF modulator box is known to fail. The one my VIC-20 came with wasn't working, even though it was a near-mint in-the-original-box system. So, I substituted a Commodore monitor cable, which connects to the 5-pin DIN on the back of the VIC and gives composite video and audio outputs.

patscc
February 14th, 2009, 08:51 PM
I thought the stock modulator that came with the VIC's had the twin-lead 300 Ohm output ?
patscc

vwestlife
February 14th, 2009, 09:00 PM
I thought the stock modulator that came with the VIC's had the twin-lead 300 Ohm output ?
patscc
Mine has an RCA jack, just like the RF output of a C64. You need a switchbox or adaptor to hook it up to a TV.

channelmaniac
February 15th, 2009, 04:56 AM
No offense, but are you plugging it into the red, white, or yellow RCA jack? If so, those are not RF inputs, but rather composite video & audio inputs.

You need to get the RCA to F connector adapter at your local Radio Shack and hook it to the big silver F connector that has the threads on it.

Also, the stock RF modulator has the RCA jacks on it. The stock RF switch box had the twin leads.

RJ

Dirk
February 15th, 2009, 08:39 AM
No offense, but are you plugging it into the red, white, or yellow RCA jack? If so, those are not RF inputs, but rather composite video & audio inputs.

You need to get the RCA to F connector adapter at your local Radio Shack and hook it to the big silver F connector that has the threads on it.

Also, the stock RF modulator has the RCA jacks on it. The stock RF switch box had the twin leads.

RJ



I am not offended at all. I feel a little sheepish but I have to admit that I had been trying to do as you had described. I was given a RF modulator box without the twin leads. Someone had already put a RCA to composite video cable on the modulator box, which is what through me off.

I have to admit that when I brought the vic-20 home I was really excited, to the point of not reading the directions. It took me a while to realize that I had actually played games on one of these when it was new, over at a friend’s house. It is already bringing back memories.

Thanks for the replies,
Dirk

Vint
February 15th, 2009, 09:38 AM
. . . . I have to admit that when I brought the vic-20 home I was really excited, to the point of not reading the directions. It took me a while to realize that I had actually played games on one of these when it was new, over at a friend’s house. It is already bringing back memories.

It's great to see someone still get a kick out of a VIC-20 :)

After my TRS-80 Model 1, the VIC-20 was my next computer, way back in the early 80's, and I really enjoyed learning on the VIC. I now have a very nice, and still working fine, VIC in my collection.

Dirk
February 15th, 2009, 02:48 PM
Hello again,

I went to Radio Shack. I picked up a male RCA to male F adapter and 6 feet of coax (female F to female F connector). I plugged the male RCA end into my RF modulator, and the F end of the coax into the back of the big male F plug on the back of my TV. I plugged the video cable from the modulator box to the back of the Vic.

I set the RF modulator switch to channel 3. I then turned on the TV, and set the channel to channel 3. The TV displays nothing but snow at this point.

I then turned on the Vic and red LED is illuminated. After waiting about 2 seconds the TV displays a vertical line from top to bottoms of the screen. The line is directly in the center of the TV. The line is about 2 inches wide and bright white. If I turn the sound up on the TV all I hear is a high pitched whining noise.

I never see any messages of any kind on the screen. I don’t have a game cartridge installed at this point.

The Vic came with a book called “Personal Computing on the Vic20 a friendly computer guide”. The book was published by commodore electronics, ltd.

This book indicates that I should see a message that says something to the effect of “BYTES FREE” and a cursor, just a few seconds after boot. I never see such a message.

Anyone have any experience with this type of situation?

Thank you,
Dirk

patscc
February 15th, 2009, 03:08 PM
Do you have a soldering iron & would you mind cutting up a plain RCA (regular stereo cable) ?
Maybe even a piece of stiff copper wire ?
It's pretty simple to wire up an ugly adapter that let's you take the video out from the VIC directly to the video in of a whatever.
Post back if you want to give it a shot.
Oh, do you have a volt-meter or multi-meter, or anything like that, by any chance ?
patscc

Vint
February 15th, 2009, 03:49 PM
. . .I went to Radio Shack. I picked up a male RCA to male F adapter and 6 feet of coax . . . I plugged the video cable from the modulator box to the back of the Vic. . . TV displays a vertical line from top to bottoms of the screen. The line is directly in the center of the TV. The line is about 2 inches wide and bright white. If I turn the sound up on the TV all I hear is a high pitched whining noise. . . book indicates that I should see a message that says something to the effect of “BYTES FREE” and a cursor, just a few seconds after boot. I never see such a message. . .

Well, it looks to me that you've got it hooked up correctly for RF. If what you have going looks like this -

http://www.vintage-computer.com/vcforum/picture.php?albumid=14&pictureid=275

It doesn't sound good, what you describe about the white vertical bar. I'll leave that to some other forum members to help with - but it sounds to me like you've got a definite problem with that VIC-20. Install a game cartridge before you turn it on and see if you get the same vertical bar business.

The unexpanded VIC-20 boot screen should look like this -

http://www.vintage-computer.com/vcforum/picture.php?albumid=14&pictureid=274

vwestlife
February 15th, 2009, 04:24 PM
It's certainly possible that the RF modulator box is faulty. Mine was!

But first make sure the TV is set to the correct channel. If you have the RF modulator set to channel 3 and the TV tuned to channel 4 (or vice versa), you will usually get some kind of fuzzy garbled image when the computer is switched on, but obviously not the correct display.

If you're handy with a soldering iron, you can get some more parts from Radio Shack and make your own composite video and audio cable, bypassing the RF modulator and TV antenna connection entirely. Connect Pin 4 (Video Low) of the VIC's DIN jack to the center pin of the composite video cable, and pin 3 (Audio) to the center pin of the audio cable. Connect the outer shields of both the audio and video cables to pin 2 (Ground) on the VIC.

http://www.ntrautanen.fi/computers/hardware/misc/images/vic_video.gif

Just be careful not to connect anything to pin 1; it is the voltage that powers the external RF modulator box, and you don't want it mixing into your video or audio connections.

Or, you can buy a pre-made video/audio cable for the VIC-20 from various sellers online, typically for about $6 to $7 plus shipping. Make sure it is a 5-pin cable for the VIC-20 and early C64 (also compatible with the Atari 800, TI 99/4A, and various other home computers). An 8-pin "luma/chroma" video cable designed for the later C64 and C128 will not work with a VIC; it won't even physically fit into the jack due to its lack of the extra pins.

tezza
February 15th, 2009, 04:57 PM
Or, you can buy a pre-made video/audio cable for the VIC-20 from various sellers online, typically for about $6 to $7 plus shipping. Make sure it is a 5-pin cable for the VIC-20 and early C64 (also compatible with the Atari 800, TI 99/4A, and various other home computers).

I got one of these from e-bay for about that price for my Vic-20/C-64 and 8-bit Ataris. Works well, and because it's a more direct signal, you get a far better picture.

Tez

Dirk
February 15th, 2009, 05:49 PM
Do you have a soldering iron & would you mind cutting up a plain RCA (regular stereo cable) ?
Maybe even a piece of stiff copper wire ?
It's pretty simple to wire up an ugly adapter that let's you take the video out from the VIC directly to the video in of a whatever.
Post back if you want to give it a shot.
Oh, do you have a volt-meter or multi-meter, or anything like that, by any chance ?
patscc


Yes I have a multi-meter and soldering iron. I do not mind cutting up a plain RCA cable. I have one I can use. I also have a digital cameral for taking photos of what I am working on/ how I am doing things. I am not sure how to upload photos though. Just let me know what you have in mind and I will go for it.

I have a female F connector on a pair of old rabbit ears that I could sacrifice. This F connector has two screws on it. I also have some 12-2 with ground house wire in my garage that I could use. Is this the kind of stuff I might need? I am not worried about the TV as it is from 1990 and only 21" inch. It only has a male F connector on the back.

Thanks to everyone for the help!
Dirk

MikeS
February 15th, 2009, 08:38 PM
I think I gotta go with Vint on this one; if that vertical white bar is fairly crisp and well-defined (as opposed to fuzzy and snowy) then it sure sounds like you've got a Problem.

Is there any sign of activity in that white bar when you type? How about when you put in some of those carts - any signs of life? Any sound?

If you do hack a direct audio and/or video cable, of course that would have to go through the VCR; that does work OK I assume?

Good luck!!!

patscc
February 15th, 2009, 09:11 PM
Okay, cut the RCA cable. If it's a stereo cable, you can use one for video & the other for audio, but for now let's just do the video:
This all refers to the excellent picture posted by vwestlife.

Seperate the copper braid shield from the inner conductor, give yourself 1.5 ~ 2 inches to work with. Twist up the copper braid shield.
Tin about 3/8 inch of the tip of the twisted braid. This works best if you can clamp the cable in a vice. If you don't have a vise, wedge it between two soup (or beer) cans, this way, you'll have one hand to hold the solder & the other the iron.
Strip about 3/8 inch from the center conductor. This tears easy, so do it gently.

If you have some stiff copper wire( like Romex ), do the following:
Strip about 3/8 off the wire. Tin, solder the tinned copper shield to it.
Cut the stiff wire so you have an inch or so, and take off the insulation.
Do the same procedure with the center conductor.
When done, the RCA cable should be attached to two copper 'prods'

If you don't have the copper wire, just make do with the tinned RCA cable. Don't use paper clips, it can be a real pain to try and get solder to stick to a paper clip.

The way the pins are counted is a bit odd if you're not used to it, so make sure to look at the picture.
Put the copper braid shield into the hole labeled 'GND' (2). Put the Center conductor into either VIDEO LOW(4) or VIDEO HIGH(5) (they're connected in the VIC).
Okay, now take your multimeter, and measure AC & DC between the pin and collar of the RCA jack. This is just so you don't fry your video input.
If AC is below about 1.5 volts or so, you're good.
If DC is below about 1 volts or so, you're good.

While you're at it, you might want to check the power supply voltages as well.

Okay, you can now take this RCA jack, and plug it into the Video IN on your VCR.
Because of the way sync is processed in TV's and VCR's, if your voltages are okay, you won't fry your equipment. (Although if it looks funny, don't leave it on for a long time), and see what happens.
If it doesn't work, take some pictures, and we'll walk you through uploading. Do you have a photobucket account, by any chance ?

patscc

Dirk
February 16th, 2009, 06:13 PM
Well the short story is that the problem is fixed. I now have a working Commodore Vic20. The long story is that I have a completely different Commodore Vic20 now. I also have a lot more than I had originally wanted. I want to thank everyone for their help in trying to correct my situation.

If you want to hear the long story then read on. It all started when I phoned a local recycler and asked them if they had any Commodore Vic20 computers. They said they did. They said that I could pick up a Vic20 for about $29.00 in decent shape. I figured what the heck I will go get just that one item. They even said that they would test it for me before hand. So I go there…

And so I could not have this without that and so on… I ended up walking out with the following stuff:

Commodore Vic20 including power cords and Vic20 to RCA cable
Commodore 1084 monitor
Commodore 1541 floppy drive with a box of 25 DD disks
1530 Datassette Unit model C2N

Assorted books:

Kids and the Vic
Personal Computing on the Vic20
Vic20 Programmer’s Reference Guide with Vic20 Schematic Main Logic diagram
Vic Revealed
Vic Games
Vic Graphics
Stimulating simulations for the Vic20

Assorted Cartridges:

Programmer’s Aid Cartridge
Fourth Encounter – game
The Sky is falling – game
Machine Language Monitor Cartridge

And an interesting item I was told was kind of rare.

The Dalco memory expander, v20-27k includes:
27k memory expander
Three ROM sockets
An expansion connector

At any rate the Vic20 works fine, I test the floppy by formatting a disk and saving a simple program. I have not yet tested the Datassette player. I have sound I have video, life is good. I am in Vic20 bliss.

I also tested the original Vic20 with the Commodore 1084 monitor and got a white vertical bar. I am not even using the RF modulator box. The original Vic20 is prettier its case is not faded at all. I guess it is a spare?

Dirk

patscc
February 16th, 2009, 06:36 PM
That's now it starts... :)

If you get a chance, could you post a picture ( or I can PM you my email, and you can just email me the picture ) of the white stripe ?
patscc

tezza
February 16th, 2009, 06:41 PM
The original Vic20 is prettier its case is not faded at all. I guess it is a spare?

Dirk

Hi Dirk,

If you like the look of the original case, you could always simply swap the working board into the original case.

Tez

channelmaniac
February 16th, 2009, 07:19 PM
You can also swap around socketed chips to see if one of those is bad.

Vint
February 16th, 2009, 07:25 PM
Well the short story is that the problem is fixed. I now have a working Commodore Vic20. The long story is that I have a completely different Commodore Vic20 now. . . .And so I could not have this without that and so on… I ended up walking out with the following stuff:

Commodore Vic20 including yada, yada, yada . . .

I have sound, I have video, life is good. I am in Vic20 bliss.

Now don't you just love happy endings :D

Who needs an 80 column screen anyway! AND notice how utterly fast she boots up! And with 3583 Bytes free, why that's practically unlimited memory!
Yep, it's easy to make fun of the VIC-20, but Commodore sold something like 2.5 million of them back in the 80's!

patscc
February 16th, 2009, 07:54 PM
So I guess the screen on the first one is a 1-column screen ?
Very minimalist.
patscc

rebeltaz
February 16th, 2009, 10:51 PM
I've been reading this thread with interest. I was hoping that someone would find a solution to what I find to be an interesting problem. The only time I have ever seen a single white line on a television screen going from top to bottom like you described was in a set that had a defective horizontal drive circuit. And more often than not, the TVs that I get in have that white line going horizontally - a defective vertical circuit. Obviously, that isn't yourproblem, since you have full screen snow and the problem appears on a dedicated monitor as well. And since the problem appears without the RF modulator in the equation, that only leaves the VIC itself. I've never seen a video output device - computer, VCR, DVD, laser disc, etc - display just a single line, though.

If you ever get this figure out, I hope you'll share with the rest of us....

carlsson
February 17th, 2009, 06:53 AM
The Dalco memory expander, v20-27k includes:
27k memory expander, Three ROM sockets, An expansion connector
Hm, at least one or even two of those ROM sockets must shadow the RAM expansion if installed. It depends on which size the ROMs are supposed to be, 4K or 8K. On the other hand, any additional cartridge plugged into the through slot could allocate any memory block so I suppose the expander passively would let through anything, however that works electronically. I also suppose it has a bunch of switches for various memory configurations and possibly swapping in the ROMs.

patscc
February 17th, 2009, 09:50 AM
That's why I was kinda hoping for a picture. The vertical line points to something that's clearly synchronized with hsync, which in turn looks more like a memory issue than anything else, or possibly the 74LS138 being latched-up, or something like that.
patscc

Dirk
February 17th, 2009, 06:04 PM
Hi,

I just uploaded some photos to Dirk_Album on photobucket.

I am not sure how to share them here. One is of the vertical line and three are of the 27K memory expander card I have showing the vic20 I just got with 28159 bytes free.

I think this link is to my album
http://s673.photobucket.com/albums/vv100/Dirk_Album/

Dirk

patscc
February 17th, 2009, 06:40 PM
Copy the img tag under the picture.
Here's a sample:

["IMG]http://i673.photobucket.com/albums/vv100/Dirk_Album/27KVic20.jpg[/IMG"]

The "" are just in there so that it doesn't get rendered in the code block, which sounds like a bug, by the way.

Here's what it looks like:
http://i673.photobucket.com/albums/vv100/Dirk_Album/27KVic20.jpg

patscc

patscc
February 17th, 2009, 06:46 PM
I took the liberty of embedding Dirk's picture.
It's the Da**dest thing I ever saw. I don't suppose you have an oscilloscope, do you ?
Is there anyway I can talk you into letting me borrow it for a while if I pay for shipping both ways ?
http://i673.photobucket.com/albums/vv100/Dirk_Album/VerticalLine.jpg
patscc

Dirk
February 17th, 2009, 06:57 PM
My Dad has an old Scope I think. He was an Electrical Engineer.

I have no idea how to use the scope myself.

I am ok with you working on this Vic20 if you want to. I can not let you pay for shipping though. I will take care of it. PM me your address and I will ship it too you when I have a chance.

And thanks for the tip in how-to post the photos.

Dirk

patscc
February 17th, 2009, 07:18 PM
If you have access to the scope, I can walk you through it. Do you have it handy ? Can you get either the make/model or a picture of the front control panel ? You'll also need a probe, which usually has a BNC (kinda like the RF connector on your TV, but you twist it to lock it) on one end and a pointy tip & alligator clip on the other.
patscc

Dirk
February 17th, 2009, 09:29 PM
I don't have the scope handy. The scope is at my Dad's house. I will have to get back to you when I know more or if I can borrow it. I am guessing that my Dad would be happy to show me how it works.

Sorry for moving off topic but might be interesting...
My Dad was in a computer club a long time ago. He had some computer with 8" dual floppies that he was working on. To make a long story short I called Microsoft and asked them if they wanted it in their museum. I ended up donating it to them, and later got a letter saying that they no longer had it. They said they wanted it because it illustrated what engineers were working on in clubs when personal computers were coming of age. I am kicking myself now because I don't have it. At the time that I gave it to MS I thought it would be on display. Stupid me...


Dirk

Terry Yager
February 17th, 2009, 10:13 PM
How very rude of them. If they were going to get rid of it, the least they should have done is offer it back to you first! Did they at least send it to another museum?

--T

Dirk
February 18th, 2009, 04:33 AM
I have no idea what happened to it, and is a real sore spot with me. The computer included all of my Dad's hand written notes and logic diagrams. I only am aware of the one computer museum here in Seattle. I have no idea where else it might have gone. The computer was square and covered the top of a card table completly. It also included a monitor and keyboard. My Dad may have had the computer case fabricated, and then used parts he obtained from the computer club.

He also had some old computers he built that have nothing but LEDs on them. I should talk to him about them. Perhaps get a photo or two.

Dirk

carlsson
February 18th, 2009, 07:29 AM
That memory expander is cool looking. On the Denial forum it was mentioned this eBay seller up to now has sold a handful of identical Dalco expanders, somewhere around $35-50 each. These are still for sale:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=310122587051
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=310096079334

I suppose they are not newly manufactured though, as one probably would use a different memory chip than 6116 on a modern design?

channelmaniac
February 18th, 2009, 09:23 AM
You could, but the 6116 is still readily available and simple to work with.

oneelkruns
March 6th, 2009, 08:03 PM
Do you have a soldering iron & would you mind cutting up a plain RCA (regular stereo cable) ?
Maybe even a piece of stiff copper wire ?
It's pretty simple to wire up an ugly adapter that let's you take the video out from the VIC directly to the video in of a whatever.


I, too, would like to connect the VIC to a composite video input. I tried a quick test with what appears to be pin 2 (GND) and pin 5 (video high) according to the pinout given above with no result. On my VIC the DIN-5 connector is upside down from the drawing on the website.

What's the procedure you'd follow to get a composite video out from the VIC?

Ron

patscc
March 6th, 2009, 08:40 PM
oneelkruns said...hat's the procedure you'd follow to get a composite video out from the VIC
Look at posts 16 & 20 on this thread.
Do they answer the question, or did I miss something ?
patscc

oneelkruns
March 7th, 2009, 06:35 AM
Look at posts 16 & 20 on this thread.
Do they answer the question, or did I miss something ?
patscc

My bad.. first time using the forum and I didn't see those posts or pages until now. They are more than enough to put the cable together.

I must say I'm glad I stumbled onto this forum. I'm sure I'll be referencing it often from now on.

Ron

oneelkruns
March 7th, 2009, 02:16 PM
Just a follow up.. the cable was simple to build and works nicely.

FYI.. my local Radio Shack did not have DIN-5 connectors so I stopped by the local music store and told them I needed male MIDI connectors and they had nice metal ones for a couple of bucks.

Ron

patscc
March 7th, 2009, 03:07 PM
Glad it's working !
Now if only the 6-pin serial cable was as easy to find !
patscc