Green screen A500

[curtis]

Got my main 500 working and was getting ready to do the memory upgrade to another 6A motherboard but decided to check it before doing all the soldering.

Good thing.  It green screens on me!

Am I correct in believing this is a RAM problem?

If so, since I have enough chips, would it be simply a case of pulling out old chips and replacing with new ones?

Thanks,

Curtis

[curtis]

Oh, and before anyone asks, yes I reseated Agnus.  No joy.

[stevee617]

Open up your A500, turn it on and let it run for about 5 to 10 minutes. Then put your thumb on the Agnes chip. if it's like REALLY HOT, then your Agnes is toast.

I had a similar thing happen. I received some guidance on this...low and behold... it was very hot. I found one on eBay, replaced it, no more problems!

[curtis]

Nope.  Not hot.

I happen to have a spare Agnes and even tried it.  Same response.  BRIGHT GREEN!

I even tried a mini mega memory.  That at least changed the color to a VERY BRIGHT YELLOW GREEN!

So, I don't think the Agnes is the problem.

Curtis

[curtis]

Okay, the plot thickens.

I forgot to mention I had installed an Indivision ECS flicker fixer so I could use my LCD screen.

Anyway, before ripping out RAM chips and resoldering new ones in, I decided to drag out my old 1084 monitor and remove the Indivision ECS just to see if it might be interferring.  Insert Workbench screen came right up!

My 500 is a stock rev. 6A motherboard.  I was told the 2 were compatible.  I looked on the Indivision board and could only find one jumper, the one to designate it as a secondary display.  Does this need to be moved?

Any suggestions?

Curtis

[dreamcast270mhz]

Go ahead and try it.

[curtis]

Did a little more digging and have a question for the gurus.

What would happen if a person was to install an Indivision ECS flicker fixer into an A500 which has the original Denise chip?

Perchance, would there be a memory problem prompting a green screen?

I'm not at home right now, but for some reason I think that's what I'm dealing with.

Can someone confirm?

Curtis

[Zac67]

I'm not too familiar with the inner workings of the Indy but it should be a rather passive piece of hw, grabbing the data flowing into Denise and reprocessing it. I guess it works fine with a Lores Denise - but the small print says it requires an ECS Agnus.

[mechy]

Open up your A500, turn it on and let it run for about 5 to 10 minutes. Then put your thumb on the Agnes chip. if it's like REALLY HOT, then your Agnes is toast.

I had a similar thing happen. Mechy gave me guidance on this...low and behold... it was very hot. I found one on eBay, replaced it, no more problems!

 Um no,i never said agnus needs replacing if it gets hot, agnus always runs hot. the ram chips on the other hand can sometimes be bad if one gets really hot.

mech

[mechy]

Did a little more digging and have a question for the gurus.

What would happen if a person was to install an Indivision ECS flicker fixer into an A500 which has the original Denise chip?

Perchance, would there be a memory problem prompting a green screen?

I'm not at home right now, but for some reason I think that's what I'm dealing with.

Can someone confirm?

Curtis

According to what i read,the indivision ecs works with the ocs or ecs denise chip so thats not the trouble. are you installing it the right way? (i don't have one so i'm not sure if its possible to put it in wrong).
the green screen suggests chip ram,although the indivision claims to work with 1MB,but they recommend 2MB.since the 500 boots to insert disk screen without the indivision,it seems to be fine. I suspect the indivision has a problem,but not sure what. are you sure its seated right with all pins in properly?

sorry can't be of more help

mech

[curtis]

Just got home and checked my Denise chip.  It's an 8362R8.
Yep, double checked the install on the Indy.

When I power up with the Indy in place, I get the splash screen for the adapter, then the 500 goes through a couple of shades of black/gray, then green.

Take the adapter out and put Denise back in place, power up, and normal boot routine.

I think I'm going to try and locate an ECS Super Denise and see what happens.

Fortunately, I have enough projects I can put this aside and work on something else while I wait for delivery after I find a source for Super D.

Will post results when I get the newer chip in.

Curtis

[stevee617]

Mech is right! It was the RAM chips! My mistake on my part! Confusion on my part!

To further clarify...My RAM chips weren't hot on my A500....but my Agnes chip was very very hot. I had an older 512K Agnes from another A500 I did swap mine and it did correct "my" problem. Later, I found another 1 Meg Agnes on eBay and put it in the A500 in question and no more problems.

[curtis]

Found a ECS Denise on ebay.  Should have it in a couple of days.

Stand by to stand by...

Curtis

[curtis]

Got the Super Denise in and here are the results.

First 6A motherboard, flickered gray, white, then green.  Powered off and tried again.  Straight to green.

Second 6A motherboard  went straight to green.

Rev 5 motherboard.  No problem!  Booted right up.

What I did with each motherboard was start out in stock configuration with OCS chips around.  Then switched out either Denise, or Agnus, or added Indy.  As a rule, even this orderly one at a time change made absolutely no difference.

Methinks I have 2 bad 6A motherboards.

An interesting note, I had modified one of the 6A's to use trapdoor memory as chip RAM.  I tried installing a trapdoor expansion, but...that is such a lovely shade of green, isn't it?

So, now I have a Rev. 5 motherboard expanded to mini-mega memory, Indivision ECS with Super Denise and am about to start putting it back together.

Of course, now I have 2 borked 6A motherboards and extra cases, et al.

Hmmm.

Curtis