Joust 131 error (power supply rebuilt and ram conv done)

trissa

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Joust 131 error (power supply rebuilt and ram conv done)

Went thru power supply. Did the ram conversion to 4164. Still banging head on 131 error. would appreciate anyone willing to walk me through figuring this error solution out. where do I look next.

Please Help.

Trissa
 
What does the screen look like? Do you get any of the "rug" pattern? Anything dynamic on the screen at all? Pics or video might help.

The "1-3-1" error can be caused by a number of different issues. Essentially, it means that the CPU isn't able to write to and/or read from the main RAM.

Obviously, double/triple check your work on the 4164 mod, and all of the voltages.
Carefully check the board all over, front and back, for any damage to traces.

Out of the 6 CPU boards I've recently been working on, two had a bad decoder PROM. Swap those out if you have spares.

Beyond those, you're likely going to need some sort of test equipment. Do you have a logic probe or o-scope?
 
Here is the vid.

I have both probe and scope but have little experience with either.

I have double check.

I don't have spare decoders.
 

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Here is the vid.

I have both probe and scope but have little experience with either.

I have double check.

I don't have spare decoders.

Check the connectors and make certain none are backwards. There is a few inter locks on that game and slam switch.

My guess is that it is watch dogging but probe the reset pin of the processor and see what that is doing. If it is flashing like a rr xrosing then there is shorting pad that you can use to disable the watch dog then use the scope to look at the data lines to see what they look like. The pads I am talking about are from pin 10 of 5H to R45 and pin 2 of 5I.

Set logic probe for ttl logic and pulse then see what pin 37 of 1E is doing and report back. Maybe even jot down what all of the pins on that chip are doing.

EDIT:

Welcome to klov.....
 
When you did the conversion to the 4164's, did you use an adapter or did you just cut the traces on the MPU board?

There are several versions of how to mod the MPU board out there and most of them are wrong. You have to make sure pin 8 & pin 9 are both tied to +5V or you will not power the chip. Pin 8 is voltage in (+5V) on the 4164 and pin 9 is address line 7 (A7). If A7 is allowed to float then you can randomly swap internal memory and any RAM tests will fail.

ken
 
Thanks for the welcome.

Here are the logic probe results

1-L
2- H
3- L > H >L > H
4 - H
5 - L
6 - L
7 - H
8 - 10 MHz signal
9 - 10 MHz signal
10 - 10 MHz signal
11 - 10 MHz signal
12 -H pulse
13 - 10 MHz signal
14 - 10 MHz signal
15 - H Pulse x3 -> all lights and audio back to H pulse x3
16 - same as 15
17 - same as 15
18 - 10 MHz signal
19 - 10 MHz signal
20 - 10 MHz signal
21 - 10 MHz signal
22 - 10 MHz signal
23- H
24 - 10 MHz signal
26 - 10 MHz signal
27 - 10 MHz signal
28 - 10 MHz signal
29 - 10 MHz signal
30 - 10 MHz signal
31 - 10 MHz signal
32 - 10 MHz signal
33 - 10 MHz signal
34 - 10 MHz signal
35 - 10 MHz signal
36 - 10 MHz signal
37 - 10 MHz signal
38 - 10 MHz signal
39 - H
40 - 10 Mhz signal
41 - L
42 - H

If something really looks screwy I will test.
 
Last edited:
Thanks for the welcome.

Here are the logic probe results

1-L
2- H
3- L > H >L > H
4 - H
5 - L
6 - L
7 - H
8 - 10 MHz signal
9 - 10 MHz signal
10 - 10 MHz signal
11 - 10 MHz signal
12 -H pulse
13 - 10 MHz signal
14 - 10 MHz signal
15 - H Pulse x3 -> all lights and audio back to H pulse x3
16 - same as 15
17 - same as 15
18 - 10 MHz signal
19 - 10 MHz signal
20 - 10 MHz signal
21 - 10 MHz signal
22 - 10 MHz signal
23- H
24 - 10 MHz signal
26 - 10 MHz signal
27 - 10 MHz signal
28 - 10 MHz signal
29 - 10 MHz signal
30 - 10 MHz signal
31 - 10 MHz signal
32 - 10 MHz signal
33 - 10 MHz signal
34 - 10 MHz signal
35 - 10 MHz signal
36 - 10 MHz signal
37 - 10 MHz signal
38 - 10 MHz signal
39 - H
40 - 10 Mhz signal
41 - L
42 - H

If something really looks screwy I will test.

sorry for the long delay, I was driving from Minnesota to Maryland by way of Kansas. I will look at the schematics and get back to you. Right now we need to look at the reset line of the cpu.
 
Ok quick look at the schematics, probe pins 34 of ic10 should be a 6821. Also probe pin 40 of ic 9.

These are the reset lines and if what I suspect is true they will be flashing like a rr xing. They should start out low and go high and stay high.
 
IC9 pin 40 and IC10 pin34 start low then stay high.

You must have drove right by me... I'm a few miles south of I90 in SW Minnesota.
 
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