Help getting Robotron running

Chupperson

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I recently acquired several new machines, but most of them are not fully functional. This Robotron seems pretty promising though.

This is what it's doing right now. It does not coin up.
https://www.youtube.com/watch?v=J0ZSym0PRXE

It was giving me a 1-1-4 error, so I replaced that RAM chip with a new hacked 4164 (I'm planning to do a full RAM swap once I get the parts to make an adapter for 4164s.) Anyway, once I replaced that RAM chip, it hasn't displayed the error but it keeps displaying a weird symbol like this http://chupnet.com/images/robotron.jpg . Any idea what that could indicate?
Also, the three LEDs on the power supply board are all lit.

I checked the voltages at the RAM and I was only getting 11.8v for 12v and 4.6v for 5v. Maybe I need to put new caps on the power supply?

Any ideas are appreciated. Thanks!
 
You sure you hacked the individual RAM ok ?

People have differing opinions, but if all you need is one ram, stay with the 4116 if your game is stable (once the bad one is replaced), then why change them ?

I have a decent supply of 4116s (pulls, and some NOS). My Williams games are still happily running 4116s. I've not had one fail yet since I got the games and got them up and running.

To each their own though. If you were going to go to 4164s, I'd replace them all direct, and do an adapter, or a pin removal/bridge on the backside of the power input to the main board.
 
I recently acquired several new machines, but most of them are not fully functional. This Robotron seems pretty promising though.

This is what it's doing right now. It does not coin up.
https://www.youtube.com/watch?v=J0ZSym0PRXE

It was giving me a 1-1-4 error, so I replaced that RAM chip with a new hacked 4164 (I'm planning to do a full RAM swap once I get the parts to make an adapter for 4164s.) Anyway, once I replaced that RAM chip, it hasn't displayed the error but it keeps displaying a weird symbol like this http://chupnet.com/images/robotron.jpg . Any idea what that could indicate?
Also, the three LEDs on the power supply board are all lit.

I checked the voltages at the RAM and I was only getting 11.8v for 12v and 4.6v for 5v. Maybe I need to put new caps on the power supply?

Any ideas are appreciated. Thanks!

if you need the cap kits with the 18000uf axial or rebuild kits i have them in stock, but first i would check your connectors and headers as you can get a big voltage drop from them.
 
the caps. the MPU caps. I would know.

also, you can't mix a single 4164 in without modifying the power running to it. the 4116s have +12 running to the pin that would be for 4164 +5. simply dropping a 4164 into a board that's set for 4116s will fry the chip.
 
Right, I followed the instructions to leave pins 1 and 8 out of the socket and jump pin 9 to pin 8, giving it +5v.
 
double check your work at that RAM (not that theres much to screw up there). 4.6 is a bit low but that board would probably boot just fine at that level.

Do you still have the original 4116? If you do, put it back and see if that error comes up. Move it and see if the error moves with the RAM. You could have a bad socket.

However, I'd still rebuild the supply and its connectors, replace the three caps just below the power input on the MPU and replace the ROM to MPU ribbon cable.

If you're up for the drive drag it down to Dallas (not quite Dallas) and I'll help you fix it. :)
 
I will try reseating the original RAM to check if the error comes back. I've been working on a Tempest and Star castle today as well and haven't gotten back to Robotron.

Before it gave me the 1-1-4 error, it was also showing that weird symbol. I'm wondering if there's a cap so far gone somewhere that it needed to warm up before it was able to detect the problem or something.
 
I'd suspect the power supply and that ribbon cable between the ROM and MPU boards if they have never been changed.
 
I'd suspect the power supply and that ribbon cable between the ROM and MPU boards if they have never been changed.

I second rom ribbon cable. there's a reset button on the MPU near the power plug, you can try bending the rom ribbon around and hold it in place and press the reset button. if you're ever able to get the game to boot then you'll know it's the ribbon.

1-1-4 error is not a general error, it should be limited to just that socket. the ram rows go 1-3 left to right, assuming the ram banks are in the upper left corner, and 1-8 going bottom to top. you can pop the plastic housing off the pins and take a look to see if any pins got stuffed or if there's some kind of corrosion in there.
 
The +5vdc is a bit low. If you have another 6809E CPU, give that a try. The strange code on the ROM board could be a sign of a bad 6821 on the ROM board which will also cause the game to reboot after the rug test.

Rebuild the power supply, replace all of the power headers on all boards and the pins in the harnesses.

Good luck!

Kirk S.
 
I checked continuity on the ribbon cable pin by pin and it seemed fine. I've been cleaning the socketed chips and their sockets as well as all the pin connectors but so far no change.

I don't really have any spare parts at all so I'm just going to have to go the route of replacing things until it works. The top left connector on the power supply board had a couple of badly oxidized pins, so I assume that's a sign that it's gotten too hot and I should replace the connectors.

When cleaning I did notice that quite a few chips have extreme oxidation on the legs, so I have been scrubbing them with Deoxit and a toothbrush to try to loosen some of it. Is that expected on chips that don't have tinned legs?
 
cabinet get wet previously that you can see? that's usually caused by exposure to moisture.

if the power supply header that's in the upper left corner (the DC out) is the one with the crap pins, that could lower your voltages. if you have the obvious original grey caps everywhere, that'll obviously contribute to a drop too.

if you want a list of parts to get it done cheap, I can PM you my parts list from GPE. only downside is they had a couple caps out of stock last time I ordered, so I have to get the balance from mouser.
 
cabinet get wet previously that you can see? that's usually caused by exposure to moisture.

if the power supply header that's in the upper left corner (the DC out) is the one with the crap pins, that could lower your voltages. if you have the obvious original grey caps everywhere, that'll obviously contribute to a drop too.

if you want a list of parts to get it done cheap, I can PM you my parts list from GPE. only downside is they had a couple caps out of stock last time I ordered, so I have to get the balance from mouser.


Oh don't worry i have everything in stock ALWAYS. shoot me a pm or stop at my site for the best and only 105c full cap kits including axial caps, rebuild kits whatever needed for the williams power supplies including the +5 pot mod...;)
 
that's great. I'm not a script kiddie that needs to buy kits. oh, and I use all high quality 105 degree Nichicons too.
 
This cab doesn't show any signs of water damage, but another one I got in the same lot has some pretty bad damage like it was being dripped on so it may have been humid wherever they were kept. The caps are all original so it would probably be in my best interest to go ahead and replace everything. If you want to send me that list that'd be great.
 
This cab doesn't show any signs of water damage, but another one I got in the same lot has some pretty bad damage like it was being dripped on so it may have been humid wherever they were kept. The caps are all original so it would probably be in my best interest to go ahead and replace everything. If you want to send me that list that'd be great.

https://www.arcadepartsandrepair.co...8784-5773-09679-00-power-supply-105c-cap-kit/
https://www.arcadepartsandrepair.co...-d-8784-mega-deluxe-power-supply-rebuild-kit/
here is the cap kit and the rebuild kit with all the connectors and they list everything included in the description. let me know if you have any questions. its all in stock.
 
So far, I have replaced all pin headers and connectors on the power board, recapped the power board and sound board for good measure, replaced a blown fuse on the audio board, and cleaned all other pin connectors and socketed chips. The -5v and 12v are now very close to their intended value, but +5v is still only at 4.8v or so. I'll get new caps for the MPU board and see if that fixes the voltage.

Anyway, the problem is still happening. Is there a good way to test the CPU or the 6821, or do I just need to install new ones to see if it helps?
 
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