R-Type2 Part Identification and Schematic Request

[yaniktheyak]

Hi
I recently purchased an R-Type II board, which was sold as working and it mostly does, except there is no Red signal coming from the board.
I have traced back to a blackened component, and wondered if someone could help me find out what it is, and where I might source one from (I'm in the Uk). The 2 blue 7 lead packages with visible numbers are the same as the blackened one off to the right.

I'd also love to get hold of a schematic for the board, if anyone has a PDF of it, or knows where I could buy one.

Cheers
Ian

[opt2not]

Just a quick (and obvious question), is that an official IREM board?

I can take a look at my board and see if I can trace that part back to the video section.  

I too haven't been able to find a digital copy of the manual, but I have seen one on ebay recently:
http://www.ebay.ca/itm/R-TYPE-2-IREM-game-manual-/150842863315?pt=LH_DefaultDomain_0&hash=item231eef6ed3#ht_806wt_1163
Shipping seems kinda messed up for a paper product that would fit in a mailer envelope.    

If this manual is anything like the R-type 1 manual, then it should have the schematics in there for you to peruse.

**EDIT:  Actually, I found the R-type II Manual. Looks like it's not as extensive, doesn't include the schematics, like the R-type 1 manual.

[yaniktheyak]

Yes, an original Irem.
I did trace the red signal off the JAMMA connector to the blackened component.
So I'm pretty sure it's the guilty part.
Not so sure why it burned out though?
Wonder if it was used with a mis-wired loom?

Here is another picture  (note it is the lower board, so the top one needs removing to gain access).

It is RA15 in the middle of the picture

[ed12]

hi
the ra is a resistor arry
very comman
u can is so like replace with a home built 1
the number on the side tell's u the trick
ie ohm's/mfg-etc

ed

[yaniktheyak]

Thanks for that.
I was hoping to replace the component with one that looks the same. To try to keep it looking authentic.
Anyone know where a good uk supplier is?

[yaniktheyak]

It says 10L471G on the side.
How can I determine the ohm rating?
Or the configuration? Ladder/bussed etc.
Are all the resistors in such a package normally the same rating?

[ed12]

hi
there is 6 resister's in that array
first thing u want to do
is this,if u look at your posted pic
on the right hand side does it go to ground or vcc
this will tell us the range we need
ie pull up or pull down
either there goning to be in the 470 ohm to 10k range
it all depend's on that last leg
i just need a tad bit more info here
so some leg work is in order on your end

ed

[yaniktheyak]

Thanks for coming back to me.

Pin 1 (the one with the black marker, and box drawn around it on the pcb) is wired to ground.

The following resistances were measured on the green and blue colour output's equivalent resistor network component.  They were more or less the same readings pin for pin (green vs blue). So I'm guessing the red should measure the same.

Pin 1 to pin 2 = 1.873k
Pin 2 to pin 3 = 2.342k
Pin 3 to pin 4 = 2.340k
Pin 4 to pin 5 = 2.343k
Pin 5 to pin 6 = 2.296k
Pin 6 to pin 7 = 0.891k
*corrected pin numbers - originally got them reversed - just in case someone read this later*

Note: pin 1 to pin 2 has a 17k res in parallel, from which the video signal is sent. With the network component removed the resistance is 17k between pins 1 and 2. So I'm guessing the network has some other effect to bring the resistance down so much when put in place?

Does this help?

Thanks
Ian

[ed12]

hi
just d/l the manual
rgsd10l471g is what u need to search for
i will chk the allen bradley site as thats what it remids me off
get back to u in a byte

ed

[yaniktheyak]

Hi
Thanks for the update

Unfortunately the only manual I can find is an install / operator guide. No schematics.

Cheers
Ian

[yaniktheyak]

Found a data sheet for rgsd10l
It looks like you are right
An R=470ohm fits the pattern I measured out I think.



Now, the big question, where can I get one from. A google can't find that value, for me, anyway.

Thanks Ian

[ed12]

hi
here is what i found on ab's
this will guide u
in my mind i would just build 1

ed

[yaniktheyak]

Thanks for all your help.
I may look a little longer to see if I can find one.
But now I have the option to build, if I have no luck!!
Cheers
Ian

[yaniktheyak]

Thanks for all your help.
I may look a little longer to see if I can find one.
But now I have the option to build, if I have no luck!!
Cheers
Ian

[yaniktheyak]

Just a quick (and obvious question), is that an official IREM board?

I can take a look at my board and see if I can trace that part back to the video section. 

I too haven't been able to find a digital copy of the manual, but I have seen one on ebay recently:
http://www.ebay.ca/itm/R-TYPE-2-IREM-game-manual-/150842863315?pt=LH_DefaultDomain_0&hash=item231eef6ed3#ht_806wt_1163
Shipping seems kinda messed up for a paper product that would fit in a mailer envelope.  :- 

If this manual is anything like the R-type 1 manual, then it should have the schematics in there for you to peruse.

**EDIT:  Actually, I found the R-type II Manual. Looks like it's not as extensive, doesn't include the schematics, like the R-type 1 manual.

I emailed Irem asking for a schematic, and they very politely told me they no longer support this product. Fair enough I guess. Still a shame. A PDF would have been nice.

[DamagedGoods]

this should help with the search 470 ohm 6 pin sip
some call it a 6 pin with common or just 7 pin
if you can't find a 7 pin you can actually cut them.
so you can take a 470 ohm 10 pin sip and either cut three legs off or snip the sip.

[yaniktheyak]

I can find lots of components that look the same, but it's the resistor configuration that they don't match on. They all seem to be bussed, isolated or dual.
This configuration is for a 5 bit d2a converter. I think it's called an R/2R ladder, from googling. But no luck finding one I can buy

[ed12]

hi
if it is for the dac then it will be a ladder
where the nick is right 470 ohm is what i caught also in the part #
but and here is the but the dac will need a ladder
u could start with 470 base and work up not down from there
to build your bridge/ladder

ed

[Beley]

I took a look around at all my usual sources but no luck, in fact it seems many places dont have ANY R2R arrays, let alone the specific on you are looking for.  It shouldn't be to hard to build one with discrete components right on the PCB.

[yaniktheyak]

Thanks for looking for me.

I guess a couple of DIL 470R isolated resistor arrays and a SIP 470R isolated will do the trick. It'll look a bit messy

I've knocked up a quick test resistor array, that looks awful
If this fixes my board, I'll make one that looks better.



Thanks to all who helped.

[yaniktheyak]

Tried it out this evening.
The good news is that I now get a working test card, with red in it.
The bad news is that when it's running, I get red where I shouldn't and missing red, when I should.
I know my RA was not a perfect match, but I'm thinking these sort of errors would not be caused by a slightly out of tolerance RA. or could they?
I'm guessing when the RA blew up it took some of the surface mount IC out too. so some of the BITS in the red color don't work correctly.

The IC has had its label scrubbed. So I've no idea what it is, or how I'd swap a surface mount component, even if I had one.

Anyone got any other thoughts?
Is this a lost cause?

[Beley]

...I know my RA was not a perfect match, but I'm thinking these sort of errors would not be caused by a slightly out of tolerance RA. or could they?
I'm guessing when the RA blew up it took some of the surface mount IC out too. so some of the BITS in the red color don't work correctly.
....

Actually on a R2R ladder the tolerances are fairly important, ive seen a better explination before but this quote from wikipedia does a fair job without going into detail

Accuracy of R-2R resistor ladders

Resistors used with the more significant bits must be proportionally more accurate than those used with the lower significant bits; for example, in the R-2R network shown above, inaccuracies in the Bit4 MSB resistors must be insignificant compared to R/32 (i.e., much better than 3%). Further, to avoid problems at the 10000 to 01111 transition, the sum of the inaccuracies in the lower bits must be significantly less than R/32. The required accuracy doubles with each additional bit—for 8 bits, the accuracy required will be better than 1/256 (0.4%). Within integrated circuits, high accuracy R-2R networks may be printed directly onto a single substrate using thin-film technology, ensuring the resistors share similar electrical characteristics. Even so, they must often be laser trimmed to achieve the required precision. Such on-chip resistor ladders for digital-to-analog converters achieving 14 bits accuracy have been demonstrated. On a printed circuit board, using discrete components, high precision resistors of 1% accuracy may be employed for a 5 bit circuit, however with bit counts beyond this the cost of ever increasing precision resistors becomes prohibitive. Even for a 5 bit circuit, to achieve high accuracy, it will be necessary to select matched resistors or to adjust individual resistors to a common value by adding high value resistors in parallel.

If you have a tonne of the resistor you used i would sugest testing and picking out the good accurate ones, or getting some precision resistors.

Also, is there a graphical test mode on that board, pics of the output of that might be helpful.

[yaniktheyak]

Wow. Thanks for that.
I could do with finding a broken irem board which has these components on. And try a precise replacement.

Anyone got one that needs a new home?
I think any M72-M84 board has similar layouts.