Different TIAs?

[Mindfield]

Okay. I just spent the last two hours slaving over a hot soldering iron and an unreasonable length of soldering mesh in my attempt to resurrect my Sears Video Arcade II by replacing its TIA with one from a known-working Atari unit.

 

To that end I just sacrificed a 2600 Jr. model. The two appeared to have a very similar board layout, and their chips were the same (RIOT, TIA and the 6507 were all there -- I'd suspected that the Jr. might have combined chips or used surface-mounted ICs, but it was very similar).

 

Unfortunately, once the transplant was complete, there's still no love. It still powers on as before, but there's still a black screen as before. Now before I go jumping to conclusions that it might be something else, I first wanted to ask if there's a difference in TIA chips. Specifically, there appear to be different chip manufacturers and possibly different revision numbers.

 

The one from the Sears is marked "CO10444D-01" and is manufactured by AMI, while the one in the Jr. is marked "CO10444-31" and is manufactured by IMP. Would this make any difference? Or is a TIA a TIA regardless?

[Bryan]

My guess is: The problem probably wasn't TIA.

 

-Bry

[DanBoris]

The TIA should be interchange between the system. The TIA from your Jr should work ok in the Sears unit.

 

Were the TIA's in sockets? If so I would try taking the TIA from the bad 2600 and putting it in a good one to see if it works. Troubleshooting this way makes it easier to identify when multiple components have failed.

 

Dan

[jsoper]

I would of taken a TIA from a socketed board or bought one from Best, every time I desolder a chip,

I'm worried that the heat damaged it.

[Mindfield]

Problem is I don't know which boards (if any that I have) are socketed; if I had to guess I'd say none of them are. (The Sears Video Arcade II is, of course) The only other units I have to sacrifice are a four-switch woody and a light sixer. The 4-switcher doesn't power up so I can't confirm that it's working anyway. The Jr. I took the TIA from was known to be working before I desoldered TIA. I do have to admit to being concerned about heat damage to TIA from the desoldering though -- but I'm paranoid that way, too. I can always re-confirm that TIA works by resoldering it back into the Jr tho. At leas then I can confirm that the TIA is still fine and the problem is elsewhere. The question is figuring out where without spending another hour or two on another desoldering job ... I hate desoldering. :-P

[jsoper]

The 4-switcher is probably socketed. Maybe you could it working first.

[Bryan]

I would of taken a TIA from a socketed board or bought one from Best, every time I desolder a chip,  

I'm worried that the heat damaged it.

 

You just have to be careful. Use a piston-type desoldering pump and a medium power (20-35W) iron, and clear one hole at a time. Then go back and free any pins that didn't come loose in the process. Sometimes re-soldering and re-clearing a hole helps with problem pins (mainly due to the heat conductivity of the new flux). I use desoldering braid to clean any clumpy leftover solder from pins and holes.

 

-Bry

[Whisper]

Oh, just a quick question, are there websites that cover basic (de)soldering techniques? I have no idea what kind of tools to buy. Thanks

[Bryan]

Oh, just a quick question, are there websites that cover basic (de)soldering techniques? I have no idea what kind of tools to buy. Thanks

 

There are all different levels of equipment, but for starters you can pick up a 25-watt hobby iron and a pump pretty cheap.

 

This is a good pump for the $$:

http://www.bgmicro.com/prodinfo.asp?sid=0&...&prodid=ACS1333

 

Desoldering info:

http://www.google.com/search?hl=en&ie=UTF-...8&q=desoldering

 

-Bry

[Mindfield]

I just went over to Radio Shaft and picked up 1.5m of desoldering braid for $5 CAD, and another 1.5oz roll of 60/40 solder for $4 CAD. I was considering getting a solder pump, they had a decent one for $10 CAD, but I figured I'd stick with the braid for now.

[Bryan]

The main advantage to the pump is that's generally faster, but once you get used to both, they each have their advantages.

 

The most important thing is to make sure each pin wiggles freely before you go prying on the IC.

 

-Bry

[birdie3]

Man, all of the 6 switchers have socketed TIAs in them and all TIAs are exactly the same. You went through alot of trouble there to get that result. I have found that usually the TIAs blow if someone used the wrong power supply (ie: 12V instead of 9V). Maybe the carts aren't connecting in the cart bay.

[Mindfield]

Actually I just discovered that the 4-switch woodie is indeed socketed -- saves me a lotta trouble. :-)

 

I also discovered that I plugged in the Jr's TIA into the SVAII the wrong way -- I made the mistake of using the writing on the chips as my orientation guide when I should have used the notch. Doh!

 

S'okay, I'm gonna try it again (the right way) and see if that fixes it.

[Bryan]

Man, all of the 6 switchers have socketed TIAs in them and all TIAs are exactly the same. You went through alot of trouble there to get that result. I have found that usually the TIAs blow if someone used the wrong power supply (ie: 12V instead of 9V). Maybe the carts aren't connecting in the cart bay.

 

The 2600 should be able to sustain voltages higher than that since the power is fed through a 7805 regulator.

 

-Bry

[Mindfield]

SHE LIVES!

 

Turns out the culprit was RIOT, not TIA. I used the dead 4-switcher's RIOT, because it was socketed (thus easily transplanted) and because it might still work (the 4-switch had no power, so the problem was probably the voltage regulator or bad solder joint on the AC, thus the chips may still work). Turns out I saved myself a lotta time pillaging that Jr.

 

But I now have a working SVAII! Woohoo! Thanks to everyone for the help. Now I'm gonna hafta resolder the Jr. and apologize for the unnecessary surgery. :-)

[+Mitch]

SHE LIVES!

 

Turns out the culprit was RIOT, not TIA.  I used the dead 4-switcher's RIOT, because it was socketed (thus easily transplanted) and because it might still work (the 4-switch had no power, so the problem was probably the voltage regulator or bad solder joint on the AC, thus the chips may still work).  Turns out I saved myself a lotta time pillaging that Jr.

 

But I now have a working SVAII!  Woohoo!  Thanks to everyone for the help.  Now I'm gonna hafta resolder the Jr. and apologize for the unnecessary surgery.  :-)

 

Why don't you drop a socket in there in case you need to test the TIA again? Might save you some trouble down the road.

 

Mitch

[birdie3]

Good job!! I have read that these are rarer versions of the VCS and that they have 4 joystick ports instead of 2. What would be the main reason one would want one of theseover an earlier version? Is is because of the rarity or does this particular version do something different from all of the rest? I have yet to see one of these in action so I just thought I would ask.

[Mindfield]

They do indeed have 4 joystick ports. They also have redesigned ambidexterous joysticks with fire buttons on either side and a stick that also rotates to act as a paddle, a nifty bank of LEDs to indicate skill settings for player 1 and 2, and joystick/paddle mode. (There are two buttons to switch between joystick and paddle mode. It doesn't seem to peform much except that the joystick is disabled in paddle mode; the paddle still functions when set to joystick mode) The channel and color/B&W toggles are underneath, and there's a nice set of feet around which you can wind the RF cable. The case design was eventually reused as the body for the 7800 (minus the LEDs and buttons).

 

I still have to de-jitter the paddle part of the joysticks, though, for which I'll need to pick up some stuff to do the job.