Atari Battlezone Restoration Newbie : 2 ARegulators R29 burned. Need Help :)

[GuerreFroide]

Hi guys

I bought a pretty worn/ broke Battlezone cabinet few months back, and started troubleshooting, but this is the first experience I have with Atari cabinets.
I had the chance to get 2 AR boards with the game, so I started to plug everything.
After 1 second, a big smoke mess went from the first AR. As I like "poker", I plugged also the second, and "bing bing smoke".
The 2 parts burned were the R29 resistor.
I have a question : Is the AR definitely burned, or if I change the R29, it is back in working order?

What are clues to verify to avoid that kind of troubles?
I am on the way to change the connectors between the BZ daughter board and the vector analogic board, and clean everything, but I don't see any other thing to see.

Any help would be much appreciated!
Sincerely
GF

[D_Zoot]

This topic is probably more suited for another section of the forum, but what the heck!



Electricity follows the path of least resistance.  You have poor connections at your game board edge connector, the ARII's output is finding it's way to the game board via the sense circuit.   Too much current in the sense circuit burns that resistor.

Clean your game board edge connectors.  Replace the terminals in the connector if they appear tarnished or burnt.   Replace the burnt resistor.

D

[Kevin Mullins]

Ditto.......

Repair / replace the harness pin and check the the pcb's edge connection. (especially the grounds) Replace the resistor.

OR

Do the sense line mod.
http://www.stickycarpet.com/pinx/ar2mods.html
(still reccomend checking all connections)

[D_Zoot]

I used to suggest the sense mod, but I don't anymore.   The sense circuit works and it works just fine.  The problem lies with the edge connectors and by modding the ARII in this fashion you pretty much are bypassing the sense.   Sure, it might get the game running, and it won't burn any more resistors, but if your edge connector still has high resistance over time it too will burn, and a burnt crisp edge connector is a lot harder to repair than a burnt resistor.  I've seen it myself,  a game with a modded ARII board and a logic board that used to be salvageable, but now has an edge connector burnt to powder.

If the edge connector is clean, terminals tensioned well, and making proper connection the sense mod isn't needed.  Fix the actually problem, not cover it up.


Kevin, no flame intended mate,  I just feel pretty stong about this topic!   


D

[Kevin Mullins]

No problem...... I totally understand.

I only reccomend the mod due to the fact that so many people will "clean" the edge connector and harness, then when the current gets the better of it it will burn up another resistor or two and then they question "what the heck is going on".

None of mine are modded and have no problems out of them.
But understanding the importance of what you have said makes a difference. 
I've even gone as far as to re-tin the edge connectors to help prevent arcing which starts the whole mad process over again.

If the edge connector is clean, terminals tensioned well, and making proper connection the sense mod isn't needed.

Absolutely key information. 

[GuerreFroide]

Hi,
Thanks a lot for all replies.
I'll clean everything, especially contacts, and I'll resolder proper harness between the 2 boards, let's see what's going on after that.
Another newbie question, that i can't find on the BZ manual.
I bought 6 months ago a AR II capkit, but it is supplied with a R30 resistor, and in my case this si the R29 that burned. and unfotunately, the R is too buned to check that is the exact value of this resistor.
Are they the same value? Or any help for a detailled AR II PCB with full parts?

Thanks.
i'll update pictures when it will work.. or not

[SavannahLion]

D_Zoot, I was reading that guys modifications. Are you sure he's modifying it for the reasons you think he's modifying it for? I see absolutely no place where he explains why he's modifying it, just that he is. For all anyone knows, one of the pins could be broken or something, hence shorting the PCB. The rest of the, incomplete, tutorial appears to be a simple cap replace.

I don't own anything with an AR# board so there's no danger in one dying by my hands.

[ChadTower]

Retin the edge connectors, repin the harness connectors, and replace the big blue filter cap.  There isn't much sense in trying to repair the boards if the distribution wiring is still a problem.  Then rebuild the AR board.  That will prevent what is most likely your root cause and enable you to make board repairs without fear that things are just going to let the smoke out again.

[RayB]

Wouldn't hurt at this point to measure what the AC power supply is sending out to the board.

When I fixed my Missile Command, I did both, as Chadwick said above. I replaced the "big blue" on the power block (as it is important to have smooth constant AC going to the AR-II), then I installed a Bob Roberts AR-II rebuild kit. ( www.therealbobroberts.net ) AND finally there's a potentiometer on the AR-II that must be adjusted to output the correct 5.0v to the board when all is done.

[D_Zoot]

D_Zoot, I was reading that guys modifications. Are you sure he's modifying it for the reasons you think he's modifying it for? I see absolutely no place where he explains why he's modifying it, just that he is. For all anyone knows, one of the pins could be broken or something, hence shorting the PCB. The rest of the, incomplete, tutorial appears to be a simple cap replace.

It's up at the top of that web page I think.  This mod, and the reasoning behind it is pretty well known anyway.

If you look at where the jumpers are soldered in when doing to mod and check ARII schematics or pinout diagrams, you can see that the jumpers tie the sense lines right back to the output lines.

D

[GuerreFroide]

Hi,
Ok Ok, let's wait, I'll do an order for tons of stuff at Bob Robert's Page.
Is it possible for someone to give to me the exact type of R29?
Thanks
Mahtieu

[Kevin Mullins]

10 Ohm 5% 1/4 watt

Page 47 http://www.crazykong.com/manuals/Battlezone.man.pdf

By the way...... R30 is the same value which you mentioned you had in a kit already. 

[GuerreFroide]

Thanks a lot for all the replies
I do all my best, but manual seems a little bit in old greek for me