Atari 2600 heavy sixer just will not work

[Michael4589]

Well I went through and replaced all the caps that come with the kit, I did the  anti static diode fix with new caps ,made new anti static strips for the switches put in the new regulator ,replaced all the chips except the 4050 buffer chip that's soldered to the board (I have 20),I checked grounds all seem good ,I have good voltage in an out of the regulator ,caps are charged up good .I have voltage at the rf module, but I  still have a non working heavy sixer. WTF ! I have 100 ohms out of the rf cable. I have a three pin rf box, at the ground it's 0 the center pin is 4.96 and the last pin is 4.16 volts. When I check the 3 soldered connections at the  rca port on the board where the rf cable plugs in  for output from the rf module I get 0 from all three like I'm checking a ground ,Shouldn't I be getting some kind of readable voltage from the rf module out?I turned the system off and checked the two outside plugs for continuity to the whole ground system(case)and I have continuity,I then check the center pin to make sure I don't have continuity and that checks fine no continuity so know short. Am I correct in thinking the rf chip is bad because of no signal on the center terminal when its powered up? Any help would be great

[+Stephen Moss]

Have you check that...

The RIOT, TIA and 6507 are all getting power? Just because you have 5V coming out of the regulator does not automatically mean each of these is getting it.

Have you checked that the reset (res) pins on the 6507 and RIOT are High (5V) when the unit is on?

Have you checked that the Oscillator is working?

 

[ChildOfCv]

RF output will be a millivolt at best.  The TV is expecting the signal strength of what comes from the antenna, so they aren't going to output anything from the RF that will be readable on a standard multimeter.

 

What channel is the TV on?  I think the ancient 3-pin one outputs to channel 2?

[emerson]

Is it possible you inadvertently pulled out the through hole plating while desoldering?

 

The service manual can be found here if you haven't found it already. If you don't have an oscilloscope I recommend using an analog volt meter when measuring high frequency voltages such as the rf signal. The sample rate of a digital meter can affect the reading. A logic probe can be easily built to determine if you have a clock signal.

[Michael4589]

Ok all the chips are getting power 4.8 volts riot ,tia, mpu and 4050 buffer.The res pins are 4.9.  The phase clock on the Tia that goes to the 6507 is 1.5 volts the color delay input from the Tia is 1.9 and the clock input on the Tia(OSC) is 1.5. As far as desoldering goes the traces look good  and the plating seems to be intact.Do these numbers sound right ?With the video color output at 1.9 dose that mean it's sending the signal for the picture?If these numbers are correct aren't they saying this system is functioning the way it should and I should have a playable system?

[emerson]

By through hole plating I meant the metal inside the hole that connects the top and bottom traces. Not the actual trace on the surface of the pcb. Typically plating will be attached to the lead of the removed component if it's been pulled out. It's pretty easy to miss if the removed component has a glob of solder on the leads still.

 

Also, a surface trace that has been lifted, even if it still has continuity with itself, will have torn away from the through hole plating and therefore won't be attached to the trace on the other side. This is why it's important to have solder on both sides of a two sided pcb.

 

https://www.pcbunlimited.com/engineering/plated-non-plated-through-holes

[+Stephen Moss]

9 hours ago, Michael4589 said:

Ok all the chips are getting power 4.8 volts riot ,tia, mpu and 4050 buffer.The res pins are 4.9.  The phase clock on the Tia that goes to the 6507 is 1.5 volts the color delay input from the Tia is 1.9 and the clock input on the Tia(OSC) is 1.5.

Power voltages look good, as does the res pins, not sure about the colour delay as I don't know what you should get but will probably vary a little unit to unit. Oscillators are difficult, like audio & video they are best checked using an oscilloscope which most people don't have. All you can really say about them using a multimeter is that if you are not getting 0 or 5 then it is probably working. 

[emerson]

Can you test the socketed chips in a known working console? You could try making this simple composite mod to see if the video signal is good.

 

https://chester.me/archives/2019/02/renovating-an-atari-2600-av-mod-capacitors-and-power-adaptor-replacement/

[Michael4589]

I have a lite sixer that doesn't work either that I bought an av mod for but  I'm not quite ready to mod the heavy six to see if that works I think I'll try a new rf cable first.The guy I got the light six from said when I bought it that he thought he had another one and if he could find it he would throw it  in with the deal if this one didn't work,he found the other system its a sears tele-games heavy sixer! I'm hoping that this system works If it dose then it will definitely help me track down what's going on with the one that was working.I'll get it tomorrow cause I work with the guy.I was super busy today so I didn't get to do anything else to the heavy six.

[+-^CrossBow^-]

On 8/20/2019 at 9:12 PM, Michael4589 said:

I have a lite sixer that doesn't work either that I bought an av mod for but  I'm not quite ready to mod the heavy six to see if that works I think I'll try a new rf cable first.The guy I got the light six from said when I bought it that he thought he had another one and if he could find it he would throw it  in with the deal if this one didn't work,he found the other system its a sears tele-games heavy sixer! I'm hoping that this system works If it dose then it will definitely help me track down what's going on with the one that was working.I'll get it tomorrow cause I work with the guy.I was super busy today so I didn't get to do anything else to the heavy six.

You don't have to fully 'mod' the H6 to test the composite stuff. What is being suggested is that you wire in the composite mod just to see if you can get video output that way as the issue could very well be the RF modulator.

 

I actually have test RCA and s-video jacks soldered to loose wires that I tack in when doing mod work to test things are good before punching holes into the case work.

 

[atari-dna]

Have you checked the inter board cable for continuity?  Headers and wires. These can be problematic.