DE Jurassic Park froze during game now does not boot

[Cliff]

When it happened I was having a great game!
Machine froze during stampede and I shut it down.
After that, it would occasionally show the version of the DMD and the dinosaur gives one roar on power up.
The blanking light never lights up.
I have removed the board and tested it with a power supply at 5.01 volts and it will not boot.
I have purchased the DE test rom from Marco and I am waiting its arrival.
I also purchased a new ( to me) 6802 from PBL and the newest rom from Matts Basement.
I am waiting for all of this to arrive.
If I cannot solve my problem with the test eprom, I will be poking around with a logic probe. I own one but have not yet used it.
I also am waiting for some stuff from GPE. I got all the caps on the original PS and the sound board. I ordered some 6821s and some peripheral chips in the blanking circuit according to the schematic.
Has anyone else been thru this?

[Cliff]

Post by Cliff
When it happened I was having a great game!
Machine froze during stampede and I shut it down.
After that, it would occasionally show the version of the DMD and the dinosaur gives one roar on power up.
The blanking light never lights up.
I have removed the board and tested it with a power supply at 5.01 volts and it will not boot.
I have purchased the DE test rom from Marco and I am waiting its arrival.
I also purchased a new ( to me) 6802 from PBL and the newest rom from Matts Basement.
I am waiting for all of this to arrive.
If I cannot solve my problem with the test eprom, I will be poking around with a logic probe. I own one but have not yet used it.
I also am waiting for some stuff from GPE. I got all the caps on the original PS and the sound board. I ordered some 6821s and some peripheral chips in the blanking circuit according to the schematic.
Has anyone else been thru this?

Turned out to be a bad NVRAM chip.
I should have bought the test chip first. Figured it out right away. No boot, installed original ram and it booted right up.
Bought new NVRAM and we are off to the races....

[John Robertson]

Post by Cliff

Post by Cliff
When it happened I was having a great game!
Machine froze during stampede and I shut it down.
After that, it would occasionally show the version of the DMD and the dinosaur gives one roar on power up.
The blanking light never lights up.
I have removed the board and tested it with a power supply at 5.01 volts and it will not boot.
I have purchased the DE test rom from Marco and I am waiting its arrival.
I also purchased a new ( to me) 6802 from PBL and the newest rom from Matts Basement.
I am waiting for all of this to arrive.
If I cannot solve my problem with the test eprom, I will be poking around with a logic probe. I own one but have not yet used it.
I also am waiting for some stuff from GPE. I got all the caps on the original PS and the sound board. I ordered some 6821s and some peripheral chips in the blanking circuit according to the schematic.
Has anyone else been thru this?

Turned out to be a bad NVRAM chip.
I should have bought the test chip first. Figured it out right away. No boot, installed original ram and it booted right up.
Bought new NVRAM and we are off to the races....

The NVRAM might have gotten invalid data. If you have a suitable EPROM
programmer try clearing the NVRAM to all FFs and see if it works again.

John :-#)#

[Cliff]

Post by John Robertson

Post by Cliff

Post by Cliff
When it happened I was having a great game!
Machine froze during stampede and I shut it down.
After that, it would occasionally show the version of the DMD and the dinosaur gives one roar on power up.
The blanking light never lights up.
I have removed the board and tested it with a power supply at 5.01 volts and it will not boot.
I have purchased the DE test rom from Marco and I am waiting its arrival.
I also purchased a new ( to me) 6802 from PBL and the newest rom from Matts Basement.
I am waiting for all of this to arrive.
If I cannot solve my problem with the test eprom, I will be poking around with a logic probe. I own one but have not yet used it.
I also am waiting for some stuff from GPE. I got all the caps on the original PS and the sound board. I ordered some 6821s and some peripheral chips in the blanking circuit according to the schematic.
Has anyone else been thru this?

Turned out to be a bad NVRAM chip.
I should have bought the test chip first. Figured it out right away. No boot, installed original ram and it booted right up.
Bought new NVRAM and we are off to the races....

The NVRAM might have gotten invalid data. If you have a suitable EPROM
programmer try clearing the NVRAM to all FFs and see if it works again.
John :-#)#
--
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Thanks John,
Unfortunately, I do not have the access to a programmer; the machine or a person to do it.

The failure of the NVRAM is unusual in that it happened mid game.
I am still not convinced that the failure of the NVRAM was not a symptom of another issue.
The NVRAM was in the game for 18 months with about 200 plays or so. Probably booted up 50 to 100 times. It was never really left on for any extended time.
I recapped the power supply though the 5 volts remained the same before and after.
I also recapped the sound board. These repairs were done because I have owned the game for 14 years and have had to do nothing to it.
I have other games with NVRAM in them. Just seems odd.

[John Robertson]

Post by Cliff

Post by John Robertson

Post by Cliff

Post by Cliff
When it happened I was having a great game!
Machine froze during stampede and I shut it down.
After that, it would occasionally show the version of the DMD and the dinosaur gives one roar on power up.
The blanking light never lights up.
I have removed the board and tested it with a power supply at 5.01 volts and it will not boot.
I have purchased the DE test rom from Marco and I am waiting its arrival.
I also purchased a new ( to me) 6802 from PBL and the newest rom from Matts Basement.
I am waiting for all of this to arrive.
If I cannot solve my problem with the test eprom, I will be poking around with a logic probe. I own one but have not yet used it.
I also am waiting for some stuff from GPE. I got all the caps on the original PS and the sound board. I ordered some 6821s and some peripheral chips in the blanking circuit according to the schematic.
Has anyone else been thru this?

Turned out to be a bad NVRAM chip.
I should have bought the test chip first. Figured it out right away. No boot, installed original ram and it booted right up.
Bought new NVRAM and we are off to the races....

The NVRAM might have gotten invalid data. If you have a suitable EPROM
programmer try clearing the NVRAM to all FFs and see if it works again.
John :-#)#

Thanks John,
Unfortunately, I do not have the access to a programmer; the machine or a person to do it.
The failure of the NVRAM is unusual in that it happened mid game.
I am still not convinced that the failure of the NVRAM was not a symptom of another issue.
The NVRAM was in the game for 18 months with about 200 plays or so. Probably booted up 50 to 100 times. It was never really left on for any extended time.
I recapped the power supply though the 5 volts remained the same before and after.
I also recapped the sound board. These repairs were done because I have owned the game for 14 years and have had to do nothing to it.
I have other games with NVRAM in them. Just seems odd.

Ah, then it was FM in other words... Friggin Magic!

John :-#)#