si deluxe,bad ram,rom,cpu,sockets????

saleem

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before i get rid of the link to the pic i took of the cocktail might as well post here,i have seen other similar threads and i understand where the problem might lie,just wanted to see what experts might have to say.
2cckkd5.jpg


i have reset line prob,voltage way too high so its gnd'd.i capped the ps and rep[laced a regulator to no avail,its at 2.5v.

i replaced the crystal on this board as it was missing and i put a cpu chip which was missing also as i had a board here already with garbage onscreen so i salvaged parts from it.

the original i had here i went and changed h socket with a 28pin one and the test rom was not running right,so i went and bought a faulty one from usa that had the roms and sockets etc on.i run the test rom on it and it does nothing bar give me the thick lines,the test rom wont run,i checked strapping and s2 is gnd'd which if i am correct is right for 2716.

just want to see what experts have to say as i know invaders is real pain in ass board with probs,but,what i get now is big improvement over what i had with the old board i originaly had.

cheers guys/gals.
:)
 
First problem I see is one that I run into as well -- you're scavenging parts from a non-working board -- you don't know if the parts you're swapping are good or not.

That said, in my entirely uneducated opinion, that looks like RAM issues. What kind of 2716 is your test ROM? For me, my 2716s would NOT work unless I had S2 connected to +5v.
 
someone burned it for me and it has mm2716q on it.thanks for the tip.yes i se what you mean about nonworking scavenged parts,i can recify by buying the crystal from maplins here in uk.
:)
 
someone burned it for me and it has mm2716q on it.thanks for the tip.yes i se what you mean about nonworking scavenged parts,i can recify by buying the crystal from maplins here in uk.
:)

Looks like, from the datasheet, that it wants +5v on pin 21, which is S2. I could be wrong, someone please confirm/deny. FWIW I confirmed that my ET2716 will NOT work when S2 is on ground, by trying it with +5v, worked. Moved S2 to ground, did not work. Moved S2 back to +5v, worked.

http://pdf1.alldatasheet.com/datasheet-pdf/view/153323/NSC/MM2716.html
 
s2 and s3 needed restrapping apparently,someone told me and showed me elsewhere,i did that but,the test rom wont fire up and just get lines.i am having to gnd the reset due to high voltage that i have not managed to get to drop.
:(
 
Looks like, from the datasheet, that it wants +5v on pin 21, which is S2. I could be wrong, someone please confirm/deny. FWIW I confirmed that my ET2716 will NOT work when S2 is on ground, by trying it with +5v, worked. Moved S2 to ground, did not work. Moved S2 back to +5v, worked.

Mine would work with S2 either not connected at all, or on +5v.....but never on ground like you described. With S2 disconnected there was still like 4.5-4.8v at pin 21, so it didn't care if it was connected to +5v or not.

s2 and s3 needed restrapping apparently,someone told me and showed me elsewhere,i did that but,the test rom wont fire up and just get lines.i am having to gnd the reset due to high voltage that i have not managed to get to drop.
:(

Are the lines any different WITH or WITHOUT the test rom in place ?

The test rom will hang at the bar screen if there is a RAM problem and won't go any further until that is fixed. But it should be showing some form of a number or letter in the middle of the screen for which one is bad.
 
anyone know what value the crstal was on space invaders motherboard?

i cant see the value in the schems,for the crystal it just says axial.
:)
 
Looks like, from the datasheet, that it wants +5v on pin 21, which is S2. I could be wrong, someone please confirm/deny. FWIW I confirmed that my ET2716 will NOT work when S2 is on ground, by trying it with +5v, worked. Moved S2 to ground, did not work. Moved S2 back to +5v, worked.

http://pdf1.alldatasheet.com/datasheet-pdf/view/153323/NSC/MM2716.html


On all non TMS2716s.......S2 should be tied to +5VDC. Yes, SOME will work with it tied to ground.....Yes, SOME will work with it floating.....ALL with work with it tied to +5VDC. I don't know why people mess around so much with S2. Strap it to +5VDC and be done with it. Rant over!:)

Edward
 
On all non TMS2716s.......S2 should be tied to +5VDC. Yes, SOME will work with it tied to ground.....Yes, SOME will work with it floating.....ALL with work with it tied to +5VDC. I don't know why people mess around so much with S2. Strap it to +5VDC and be done with it. Rant over!:)

Edward

I should have noted that I did end up tieing my S2 to the 5v.... like you said, just to be done with it.
 
*Corrected: I believe its 19.968 mhz

If you find a source let me know! Digikey doesn't have them.

thanks for that,on the schems for the board it just says axial but,it does have 199680 on it,dead giveaway but,me not being knowledgable didnt realise.

all i can say is,i have strapped my board as per this pic:
206mpz9.jpg


so when the board is strapped this way,i get lines,every now and then it switchs the lines a little but,then it stops at the lines,also i have a mothership sound.

i have to get a crystal for the board i originaly had so i can try the test rom again in that board this is why i needed the crystal info,gonna save me from having to desolder and resolder the same one all the time.the sound board has 1 mylar cap missing also,so i will try to get that replaced.

i have ordered 10 ram chips and sockets and a couple of 8080 cpu chips.but,they will have to get to me from usa as i am in uk.but,thanks for the info guys,realy amazes me how good you guys are where info is concerned and how willing you are to give it.

thanks very much.
:)
 
I should have noted that I did end up tieing my S2 to the 5v.... like you said, just to be done with it.

Sorry, that wasn't directed at you. You're one of the few I've actually known to let it "float" :)

There's so much mis-information out on-line about Space Invaders strapping....particularly S2. It drives me crazy. Midway (even) released a service bulletin about it....non-TMS2716s...S2 goes to 5VDC. I just don't understand why people waste their time farting around with. Do it right and be done.

Edward
 
Sorry, that wasn't directed at you.

Nah, that's cool....your comment just reminded me I should "finish" my statement on that particular setup. (I really do try to NOT add to the confusion already out there) :)

What are the voltages for each of those? I have a different revision motherboard and the strapping area does not look the same. I'd like to at least make sure the voltages are right when I restrap it.

A pic or the revision number of your board would help.
Each spot can be either a voltage, a ground, or an address line....and of course it then depends on what type of rom you are wanting to use. Attached is one diagram marked in red for 2716's.
 

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A pic or the revision number of your board would help.
Each spot can be either a voltage, a ground, or an address line....and of course it then depends on what type of rom you are wanting to use. Attached is one diagram marked in red for 2716's.

Pics. Sorry for the mini-thread-hijack. I'd want it strapped for non-TMS 2716s.
 

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Here are two variations from the web site http://www.marvin3m.com/video/seawolf.htm
(same results, just different ways of going about it)
Just whatever you do, DO NOT tap into a 12v spot by mistake.....it'll cook your roms immediately.

S? = Fixed Point = Point you're jumpering to
S1 = ROM Pin 22 = A9
S2 = ROM Pin 21 = +5v
S3 = ROM Pin 19 = A10
S5 = ROM Pin 20 = Ground
 

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