Thoughts on a sick Astrocade

[bah]

I made a cartridge yesterday and play tested it for about 5 minutes and all seemed fine. Today I popped the same cart in and my system went for maybe 4 or 5 minutes and then it locked up and I get extra artifacts on the screen. Press the reset and the game starts again but very quickly locks up. When it is locked up, the screen graphics are still colorful and generally intact but I also get random stuff on the screen. It is the same for all games.

 

After a half hour cool down, i get about 5 minutes of play again.

 

Obviously something in the system is heating up but I am not well versed in what areas to look for the problem, so I am asking here for any advice what to look for before I open it up.

 

This is a later Astrovision unit with the Bally Computer system cover. It has had the shielding removed and aluminum heat sinks with heat transfer grease put on the 3 custom chips. I have only owned it maybe 2 years but really like it so I am hoping the problem is fixable.

 

Thanks for any advice,

 

Brent

[ballyalley]

I am hoping the problem is fixable.

 

I wish that I could be more helpful with your overheating issue and offer some sound advice, but I can at least point you in the right direction.

 

If you're handy with electronics, then you can build yourself a BalCheck unit which attaches to the 50-pin connector on the back of the Astrocade (the same connector that you hook a RAM expansion to). A Balcheck looks like this:

 

 

I have many pictures of two version of this unit on BallyAlley.com:

 

http://www.ballyalley.com/pics/hardware_pics/BallyCheck/BallyCheck.html

 

At the beginning of October, Michael Matte wrote Balcheck Supplemental Info, which is a tutorial that explains how to use the BalCheck hardware and its software to diagnose a failing Bally Arcade/Astrocade console. By coincidence, I just added it to BallyAlley.com today. You can find it (and other BalCheck documentation) here:

 

http://www.ballyalley.com/documentation/BallyCheck/BallyCheck.html

 

Michael also wrote a very detailed document called Troubleshooting the Astrocade, which I'll also be adding to BallyAlley today.

 

The Astrocade hardware is now between 35-40 years old. There's a lot to go wrong in there. The good news is that based on your description, I doubt that its one of the custom chips. Why is that good news? Because everything else in the Astrocade can still be replaced, but the custom chips are quite rare.

 

Adam

[bah]

Thanks Adam. I was guardedly hopeful that the custom chips were ok. Later tonight I will read through what you have posted. I also intend to take a look at the ram chips and see if one of these is getting hotter than the rest. Is there a single voltage ram chip that can be used in place of these 4027 chips? My experience with Colecovision units has taught me a miss-trust of the old 3 voltage chips.

 

Brent

 

PS The base of my unit has never had the edge connector slot or the light pen connector area opened up,

[ballyalley]

I also intend to take a look at the ram chips and see if one of these is getting hotter than the rest. Is there a single voltage ram chip that can be used in place of these 4027 chips? My experience with Colecovision units has taught me a miss-trust of the old 3 voltage chips.

 

I know that when Ken fixes his own Astrocade units, he likes to replace the RAM, but I don't know much about that; you'll have to ask him-- and he's always reading the Bally Alley Yahoo group.

 

Today, I have also added to BallyAlley.com Troubleshooting the Bally/Astrocade Motherboard Power-Up with SetScreen, A New Tool by Michael Matte. Michael wrote this on September 20, 2017.

 

This document is for anyone with experience in troubleshooting the Bally/Astrocade motherboard. It explains one method on how to fix an Astrocade using step-by-step methods. It was written by Michael Matte, the person who designed and built a modified Astrocade that runs with low or high resolution graphics. Specifically, this document addresses the scenario in which a blank TV screen appears when powering on a motherboard and describes a new, very useful tool to help isolate the problem area.

 

http://www.ballyalley.com/faqs/faqs.html#TroubleshootingtheAstrocade

 

Brent, maybe this newly-added troubleshooting document will also help you out. if you read this, then I'd like to hear feedback on it.

 

You may have already read Ken Lill's Astrocade Intermittent Problem Fixes that he wrote in 2008, but it can't hurt to point it out to you:

 

http://www.ballyalley.com/faqs/Astrocade_Intermittent_Problem_Fixes.txt

 

Ken has given hardware advice and feedback both here (on the AtariAge forums) and on the Yahoo group. The fact that your Astrocade works okay for a little bit indicates to me that you can probably track down the problem and fix it.

Adam

[bah]

I finally had time to look at this more.

 

When I use scribbling in demo mode, I get missing pixels fairly quickly and scribbling keeps going for a while, but I did not test it for long. The missing pixels get more frequent as it goes.

 

When I just turn it off, the problem comes right back when I start the unit, but if I unplug it, thenafter 5 minutes it will play for a short while.

 

All socketed chips are tight but I reseated them just to be sure. The one anomoly that I did find is that vr4 is getting too hot to hold. This is the -5 volt regulator. Althought the ram chips are not getting hot, the missing pixels and hot regulator probably indicate I have a bad ram chip. Does anyone here know how to verify a bad ram chip other than replacing it with a known good one?

 

Thanks

 

Bah

[+remowilliams]

If you're handy with electronics, then you can build yourself a BalCheck unit which attaches to the 50-pin connector on the back of the Astrocade (the same connector that you hook a RAM expansion to).

 

Interesting. Has nobody actually translated that mess into a nice PCB design that could easily be replicated/assembled?

[SignGuy81]

I was just looking over the schematic here

 

http://www.ballyalley.com/documentation/misc_hardware_docs/Bally/full_size/Bally%20Arcade%20-%20Astrocade%20Schematic%20%28Excerpt%20from%20PA-1%20Service%20Manual%29.gif

 

I'm guessing it is the right schematic I could be wrong.

 

VR4 looks like the -5V, and looks to me other than the ram chips that you also have -5V going to the RF circuit(scroll to bottom right of page you should see the connector ). If your ram chips aren't getting hot maybe you can unplug the connector that leads to RF and see if the regulator still gets hot, in case maybe it is something shorted perhaps in the RF circuit that is causing it. It seems to me the RAM chips would be getting hot if they were shorted, putting extra load on the VR and causing it to get hot also. Another thing is maybe the voltage regulator is simply going bad and needs replacement which could be why it is getting hot, and that voltage being to low that the RAM chips need would of coarse cause you RAM related issues.

Edited October 16, 2017 by SignGuy81

[ballyalley]

 

Has nobody actually translated that [balCheck] mess into a nice PCB design that could easily be replicated/assembled?

 

I've not heard about anyone design and/or making a BalCheck PCB layout using Eagle, KiCAD or any other PCB layout program. It would be a great benefit for the Astrocade community if somebody did take on this project.

 

Adam

[kenzre]

There are several things that can cause your problem:

First of all.. note if the artifacts as always coming up on the same places on the screen. If so, you probably have a bad DRAM chip or 2.

If not, then it could be the custom DATA chip, U23 (The read buffer for the DRAM), or your Z-80 microprocessor., probably in that order.

Try blowing a fan over the unit when you remove the top.

Putting heat sinks on the custom ADDRESS and I/O chips really wasn't necessary as they really don't get warm enough to damage themselves unless they are already bad. It also makes it harder to know which chip is which.

If the fan helps, you probably have a custom DATA chip that is on it's way out.

Putting a laptop cooler underneath may lengthen the life of the unit.

Ken Lill

[spacecadet]

Every time I see the title of this thread I read it as "Thoughts on a SICK Astrocade!" Like, this must be the most badass Astrocade ever made. With racing stripes and ground effects and everything.

[SignGuy81]

Every time I see the title of this thread I read it as "Thoughts on a SICK Astrocade!" Like, this must be the most badass Astrocade ever made. With racing stripes and ground effects and everything.

 

I thought the exact same thing at first before I clicked on it.

[ballyalley]

Every time I see the title of this thread I read it as "Thoughts on a SICK Astrocade!" Like, this must be the most badass Astrocade ever made. With racing stripes and ground effects and everything.

 

Well, if you want that kind of "SICK Astrocade," then here is a picture of it:

 

 

This Astrocade unit belongs to Michael Matte. Besides the obvious QWERTY keyboard addition, there is also an external keypad. Although the system has a Viper attached to it, that is only the case: the actual Viper hardware is not inside there, instead, it contains Michael's hi-res upgrade.

 

Yeah, there are only two hi-res upgraded Astrocade; the above picture is of the only one that still functions.

 

Is that "sick" enough for ya?!?

 

Adam

[bah]

OK I tried some stuff. Fisrt, disconnecting the RF did not keep the vr4 from heating up very quickly.

 

I ran the thing without a fan for two runs and the blank pixels are consistently in certain columns. You can mark a sheet of paper and blank pixels always happen at certain spacing and often on regularly spaced rows. Blank pixels may be overwritten and then go away but generally stay in position once on the screen. Just before the Scribbling program locks up, a coupe of the pixels started binking on and off. When locking up, the machine went back to the opning menu. The first time it took some input (I typed 4 and return and it went to the number of players screen then stopped), the second time it did not respond.

 

With a fan, the story did change considerably. It took longer to start showing blank pixels and worked for about 10 minuted without locking up. I could touch and hold the vr4 heat sink easily.

At this point I am still hoping dram, but obviously the fan did help. The custom data chip never feels anything but mildly warm, fan or not.

 

Thanks for the help all.

 

Ken, any thoughts on what I have found?

 

Brent

[bah]

Adam,

 

That is a SICK vader console.

 

Brent

[bah]

This thread does have a happy end. I have been waiting for ram chips. Over lunch time today, I took out the old chips, installed sockets and new ram chips. Tonight I ran scribbling for about 10 minutes, then Space Invaders untill the last wave that starts on the ground, then back to scribbling. Overall about 30 minutes without turning it off. I could not get over 5 minutes before.

 

I still want to replace the -5 volt regulator that was getting so hot, but for now, it seems I had at least one bad ram chip.

 

Thanks to all who responded and a good night to all.

 

Bah

[ballyalley]

Over lunch time today, I took out the old chips, installed sockets and new ram chips. Tonight I ran scribbling for about 10 minutes, then Space Invaders untill the last wave that starts on the ground, then back to scribbling. Overall about 30 minutes without turning it off. I could not get over 5 minutes before.

 

It's great that you got your Astrocade up and running again. Congratulations!

 

Adam