another dead pole position, ar2 question

cadillacman

Well-known member
Joined
Nov 25, 2007
Messages
15,504
Reaction score
542
Location
Roscoe, Illinois
got another dead pole, tried to boot but gets random atrifacts insttead.. (previous owner says it works after its warmed up.. yeah right lol prolly already have smoked pcbs)

one board has good 5v the other is getting 6.2!!!!!!!!

check the ar2s and the bad ars has 3 fried resistors and wont regulate the 5v..


what are the values of r6, r7, and r29??

would like to replace resistors and recheck...
 
still gotta find those values tho...

yeah looks like those resistors (at least one) ends up at the adjustment pot..

i dont even think a sense mod would help untill i get these resistors replaced...
 
ive got a working pp im parting out.
but it was using a switcher for the 5v i think, so not sure if this would help you or not
 
good i might need pcbs lol

found my info

r6= 3.9k 1/4 watt

r7 7.5k, 1/4 watt

r29 10 ohm, 1/4 watt

R29 is in the sense circuit.....might wanna check out the edge connector (or at least, crimp new pins on the power & ground rails).

Edward
 
ok i figured ou whats taking out my ar2..


theres something dead shorted on my video board.. cr2

loks like a diode, is it and is there any radio shack equivelent or is it a unique piece?

this sucks.. i had a whole pile of boards i gave away when i got rid of my last pp...
 
R29 is in the sense circuit.....might wanna check out the edge connector (or at least, crimp new pins on the power & ground rails).

Edward

That's what I was thinking. Even if R29 and R30 are smoked, the +5V sense circuit would still sense from the edge connector. If the edge connector isn't making proper contact, it might not regulate correctly.

Or it could be a bad 2N3055 or TIP32. Rebuild kits for those are $17 installed. :)
 
Pole Position

Hey,

Schematics and parts list show CR2 as a 6.2Volt 1 watt 5% zener diode. This zener is there to shunt anything over 6.2 volts to ground so that your board won't be TOTALLY destroyed if your power supply fails high. That is why you are reading 6.2 Volts. The 'shack' used to sell zeners but I don't know about now. You want a 1N4735A...


Fix the power supply first and make sure your board edge and the harness connectors are good/clean/replaced, then replace CR2 and try it.

Good luck.

Kenneth
 
Last edited:
Het,

Schematics and parts list show CR2 as a 6.2Volt 1 watt 5% zener diode. This zener is there to shunt anything over 6.2 volts to ground so that your board won't be TOTALLY destroyed if your power supply fails high. That is why you are reading 6.2 Volts. The 'shack' used to sell zeners but I don't know about now. You want a 1N4735A...


Fix the power supply first and make sure your board edge and the harness connectors are good/clean/replaced, then replace CR2 and try it.

Good luck.

Kenneth

I've recently started seeing a lot of those zeners failing. On Atari boards that use them....it's one of the first things I check. Even on ones with a good zeners....the solder joints are cooked. When you replace it, mount it "up" off the board a bit....give it some "breathing" room.

Edward
 
well progress at least... heres where im at...

i repaired the suspect ar2 with new resistors and a new 3055 transistor.

After verifying that i am nowe running a regulated 5 volts, i ****TEMPORARILY**** removed the shorted diode from the video board..


After adjusting thr 5 volts, my game now boots up and plays!!!!


Now i have some issues that im not sure im brave enough to tackle(thinking i mabye should be happy this bieotch works)

I have no chick talking.. just static instead :( in selftest that translates to sounds # 19, 20, and 0, iirc

all other sounds are there. Graphics look good with exception of intermittently your opponents cars turn into thin likes for a split second..


SOund like a rom reseat issue?? also this board has some really "creative" dip ic with wires soldered on and its sitting on top of one of the roms... mabye a unauthorized pp1 to pp2 conversion??/ i dont know...

whattya think fellers? if anybody thinks which rom has these sounds im missing please lmk im too scared to pull and reseat them all, id like to just try the one in question because i know damn well if i pull and reseat them all the board will never work again..

my edge connectors suprisingly look good and fit tight.. edges of the boards have been perviously repaired with copper foil and soltered at the inside edges to make cgood contact.. somebody did that right at least lol..

i will still jumper my grounds and 5 volts eventually because i know if i dont ill pay for it later...

im happy this thing is half working at least, makes me feel a little better
 
Last edited:
well progress at least... heres where im at...

i repaired the suspect ar2 with new resistors and a new 3055 transistor.

After verifying that i am nowe running a regulated 5 volts, i ****TEMPORARILY**** removed the shorted diode from the video board..


After adjusting thr 5 volts, my game now boots up and plays!!!!


Now i have some issues that im not sure im brave enough to tackle(thinking i mabye should be happy this bieotch works)

I have no chick talking.. just static instead :( in selftest that translates to sounds # 19, 20, and 0, iirc

all other sounds are there. Graphics look good with exception of intermittently your opponents cars turn into thin likes for a split second..


SOund like a rom reseat issue?? also this board has some really "creative" dip ic with wires soldered on and its sitting on top of one of the roms... mabye a unauthorized pp1 to pp2 conversion??/ i dont know...

whattya think fellers? if anybody thinks which rom has these sounds im missing please lmk im too scared to pull and reseat them all, id like to just try the one in question because i know damn well if i pull and reseat them all the board will never work again..

my edge connectors suprisingly look good and fit tight.. edges of the boards have been perviously repaired with copper foil and soltered at the inside edges to make cgood contact.. somebody did that right at least lol..

i will still jumper my grounds and 5 volts eventually because i know if i dont ill pay for it later...

im happy this thing is half working at least, makes me feel a little better

Speech is in custom chip at 9D, also investigate 9C

Your car issue is a little more trickier.....is it when the cars are off in the distance?...or near your car?...two separate circuits. Does it affect anything else...like the signs?

Nearby cars, check 12J and 13J.
Distant cars...12N, 13N....
Also wouldn't be a bad idea to probe around 12H, 11N, 13H...and the RAM at 9F & 10F.

Edward
 
reseating the custom chip and rom fixed the chick sound.. shes back!!!

however i still have this cars turning into lines issue... i reseated most of the roms on the video board section, i guess it wouldnt hurt to recheck and i guess i better check voltages again before i get too ahead of myself.. this thing has a hard timeboothing up cold, itll go through self test a few times then finally stay up...

far away, cars ok signs are ok..

in the middle, cars flat line also a section of the road signs at same distance are missing a center section

up close, cars and signs ok again..


whattya think?


EDIT +5 and ground was soldered onto a few test points and jumpered to the harness.. my hard to boot and reset issues are fixed, missing graphic issue still remains... voltage on both boards at 5.2 volts...
 
Last edited:
in the middle, cars flat line also a section of the road signs at same distance are missing a center section

I'd start here...
Also wouldn't be a bad idea to probe around 12H, 11N, 13H...and the RAM at 9F & 10F.

Sounds like it might be time to pull out the logic probe or a scope.

Edward
 
its time for a can of gas and a torch....

back to ramdom resetting and herd to boot, now its throwing random rom0 anmd rom10 errors..


fucvk this thing
 
Back
Top Bottom