Robotron error!

[joeks]

Guys, I am having a problem with my Robotron
Fired it up and now I get slow vertical blocky lines during boot and a short sound effect.
After that, nothing. Just black.
It actually started a couple days before with "Ram error 31" and sometimes other random numbers.

Had something like this before, back then I just reseated all the connectors and the error went away.
But this looks a little more serious.

Haven't really tried to find the cause, if it's not a connector thing I hope it the ram.
I still have the older 4146 ram chips. Time to upgrade to 4116's.
Does anyway here have a load of them? No time to order from the US considering I want to bring this to Eurocade next saterday!

As a backup, I can always bring my DK Jr.



EDIT. Found this http://www.mikesarcade.com/cgi-bin/spies.cgi?action=url&type=info&page=Williams-hardware.txt online.
Will try tonight!

EDIT2. My screen kinda looks like a "rug pattern" screen...
The text below is what I found on the link above.

By far the most common failure of these machines is the DRAM (type 1
failure).  This usually will produce a very organized "rug pattern" on
the screen and the game will not "boot".  Sometimes you get really weird
video or else none at all.  The solution is simple, get new DRAMs!
These are type 4116 (450 ns access) 16K x 1 Dynamic RAMs
 

[ajhippel]

4116 Rams seems to fail very often.

i recommend a small hack for williams boards to use the 4164 rams - which seems to be much more stable

actually it is very simple hack. look here: http://www.robotron-2084.co.uk/techwilliams4164.html

afaik after changing to 4164 - future ram probs should be solved

(i already did that on my defender)

[joeks]

Thanks for your reply Jochen!

Good to hear about the hack!
Now I need to find the ram chips and connector online.

[level42]

Uh, you have to go the other way around....there are now 4116s on the board (if it's original).

Checked my inventory list (man I am so organized these days ) and sadly have neither.....well not in sufficient quantity....send Robin a PM he may have some stock.

[ajhippel]

if it is not a hurry, i could bring those rams to the eurocade...

i bought some 4164 NOS (>200 pieces i guess) - so i have a lot as spare

i made the hack without a connector by (afair) soldering pin 5 and 6 of the male connector (on the main pcb) together and removing the +12(pin 5) and -5v(pin 9) wire from the female connector

i am not 100% of this - i need to check it...

the 4164 could be plugged into the sockets without bending or wiring any pins.

[joeks]

Uh, you have to go the other way around....there are now 4116s on the board (if it's original).

Oops, thanks wrote down the numbers wrong.

@Jochen,
The hack without using a connector seems an easy way of doing it. Will probably go that route.

If you could bring those rams to Eurocade, would be great.
Except for the fact that I wanted to bring my Robotron to Eurocade
I could bring my DK Jr instead of course, don't know if that's ok with the Eurocade crew.

[level42]

Yep that should work fine. It's a simple mod but some people prefer to use an adaptor connector like that so you can "go back to original". Whoever would want to go back to original RAMs that need three voltages and die by the bunch though ?

[level42]

Yep fine, we can always play Robotron on my Joust/Robotron cab, in fact....it's better as Robotron since the 2 player is still not hooked up on Joust...

I'd prefer to have the Jr. that really add a game

[joeks]

Ok great! I'll bring DK Jr instead.
That way it gives me some time to fix Robotron.

So, please Jochen, if you could bring the 4146 ram chips to Eurocade I appreciate it very much
Paypal ready, or cash.

Here's a photo I found on my phone of the chips in my Robotron.
Weird thing, only the top one in the middle row says "4116"..
Untitled by barrybuise, on Flickr

[ajhippel]

i will bring 4164(!) on friday

[joeks]

i will bring 4164(!) on friday

Thanks! Are you there on saturday as well?
Our plan is to be there from saturday morning till late evening. So not friday evening.

Oh by the way Andre, I'll bring my brother John along if that's ok.

[ajhippel]

i'll be there from friday evening 'til sunday morning

[level42]

Yes no problem as long as he also pays (kids of paying guests are free though). There's still plenty of room for more people, we are only at about 35 now.

The 9016's are compatible or equivalent to the 4116. different manufactures sometimes used different numbers for the same thing.

I bet that Texas one is the dead one try to feel for heat ...

At least that one is the oldest seeing the date code of 1980.....

[joeks]

Thanks for info on the 9016's. Looking forward to replacing them for proper 4116's though
Didn't have a chance to test yet, forgot we had a cinema-evening with work.
Will test tonight.

[Wurstkopp]

It's definitely recommended to upgrade to 4164 RAMs, but I'd first try and exchange the possible faulty 31 RAM with one from another position, for example RAM 15. If the errors then says 15 you have a faulty RAM.

Usually the 131 error is not necessarily RAM-related (it's just the first one that gets tested) and could mean nearly everything. Hope you're lucky though.