Defender Upright Not Starting Up - CPU/Video Board Problem

seybon

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Defender Upright Not Starting Up - CPU/Video Board Problem

I am a newbie on this site and also a novice when it comes to electronics. I have a soldering station but am not too good at soldering (beginner with shaky hands, lol). Am pretty good with trouble-shooting and dealing with schematics (worked on pneumatic controls and pumps for over 18 years). Like working on old classic cars.

A couple of weeks ago I bought a Defender Upright on eBay for $108. It has a different monitor than the G07 and needs a Flyback kit that I am ordering once I know the monitor type in it. Also, it has a rigged-up ATX Power Supply in it from a PC Computer.

I switched out the CPU/Video board and the monitor from my Defender Cocktail Machine and all works fine, so I have narrowed the problem to the both the monitor and the CPU/Video Board.

I will deal with the monitor and want to focus this thread on the CPU/Video Board. I know that I am going to need a Logic Probe, s I will be ordering that too. I do however have a DMM for testing if that can help.

The battery Pack/Case on the CPU Video Board was toast, so I bought a plastic one from Radio Shack and soldered longer wires to the board and will put the battery pack/case on the floor away from the board (thanks Yellow Dog for that tip).

Symptoms:
When I plug the machine in, there are no sounds, there are 4 lights that stay on on the ROM board, and the monitor is blank but glowing at the flyback (cocktail monitor). When I press the reset button on the CPU/Video Board nothing happens that I could visually see, not even a flicker of the 4 LEDs on the ROM board.

It seems that I need to start with a Logic Probe going through the Logic Probe Troubleshooting Flow Chart, as it seems to be a problem with the Reset Circuit. Can I do any testing with a Digital Multimeter here?

Also, the RAMs on the board are not 4116s or 4164s, but a combination of mostly 8119WP and 8109. What gives on this? Is this someone just putting in random RAM IC's?

I also have another CPU Video Board that is in bad shape with corrosion, but the RAMs in the are all 4716 except one of the RAMs is 8409.

Any help/suggestions in the right direction would be appreciated.

Thanks
 
Also, the RAMs on the board are not 4116s or 4164s, but a combination of mostly 8119WP and 8109. What gives on this? Is this someone just putting in random RAM IC's?

Those sound like date codes. Are there any other numbers on them?

If you are not seeing the LEDs on the ROM board flickering, there is not much yu can do without a logic probe. You will neet to look at the RESET pin on the CPU and see its state. It should be high and go low for about 1 secod when the reset switch is pressed.

The only thing that you can test now is to make sure the correct voltages are seen at the 4 corners of the RAM chips.

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ken
 
Those sound like date codes. Are there any other numbers on them?

You're right. There are actually 5 of the 4116 chips. Across the top they read MCM4116BP25 and on the bottom they read QC8109. I guess that means they are 4116 chips made in the 9th week of 1981.

The other 19 chip across the top read AM9016DPC and on the bottom they read 8119 WP. I am assuming that these are 9016 chips that were made in the 19th week of 1981. Will these chips even work in this board?

While I'm waiting on my Logic Probe, I'll check the voltages in all 24 chips.

I appreciate the help, and will report my findings as it might help anybody browsing this thread in the future.
 
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OK, so I tested the voltages in all the 24 RAM chips and got the following:

Pin 1: - 5.49 Volts
Pin 8: 12.16 Volts
Pin 9: 4.79 Volts

These all seem to be in the acceptable range as far as the power for these chips go.
 
OK, so I tested the voltages in all the 24 RAM chips and got the following:

Pin 1: - 5.49 Volts
Pin 8: 12.16 Volts
Pin 9: 4.79 Volts

These all seem to be in the acceptable range as far as the power for these chips go.

the minimum spec for +%v rail is 4.75-5.25v. given the age of these monsters, 4.79 is prob too marginal for reliable operation.
therefore you need to
- pay attention to every +5v connection from the psu to the cpu board and maker sure they are clean and free of dirt/patina/rust etc (nice and shiny).
- check every cable crimp in the harness for the 5v rail and ground/earth
- check same for every earth and ground joint between cpu board and the mounting plate/standoffs.

this should result in an improvement in the 5v rail voltage level.

try the dodgy cpu in the cocktail machine. if it doestn run fine there, then psu repair/replacement wont necessarily help. if it does run better or fine there,
- check the psu ratings for the 5v rail (what current rating ?) - does that match or exceed defenders requirements ? (check fuse ratings)
- if you have a computer power supply in this machine then these are typically not adjustable, therefore you need to:
a) replace the psu with an original defender psu and transformer (if the transformer is in the cab)
b) replace the psu with a bob roberts replacement psu kit
then adjust the psu upward so that the 5v reading at the main harness connector and at the ram is close to 5.1v but below 5.25v

then see how she performs.
 
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What Andy said. I have found that Defenders seem to run better on the high side of +5V. I have had several boards that had intermittant boots at 4.97V that were rock solid at 5.05V.

Based on the volages, you may need to rebuild your power supply board first before continuing to trouble shoot. If the power is bad, nothing else will be good.

ken
 
While I haven't dealt with the Power Supply problems yet, I did do the following while waiting for my Logic Probe to show up:

1) I tested the Power to the RAMs in my working cocktail game table. They all have RAM chips that are upgraded to 41256 chips, and pins 1, 8 and 9 are all at 4.04 Volts??? (seems weird). It works fine in the upright machine without any problems.

2) I put the not working CPU/Video Board in the cocktail game table with the same results as the upright, no startup sound, power to the video screen (neck glow) but it is black, and all 4 ROM chips on.

This still could be a Power Supply Problem as the RAM on the Cocktail Game Table is only getting 4.04 Volts, so I should also test the output of the 5V Supply from the Power Supply Board on the Cocktail Table. I don't know if the 41256 chips are interchangeable with the 4164 chips, but I thought that a 4164 chip upgrade got rid of the 5 Volts and supplied 12 volts to the 4164 chips. Is it possible that someone did a 41256 upgrade and modified the board to only supply 5 Volts (actually 4.04 Volts) to these chips? There is a sticker on the board that says "Use $1256 Chips Only. Not 4116 Chips".
 
The reason the other pins are running at +5V is to force the chips to only use one 16K bank of RAM. If they were allowed to "float", there would be no guarantee which of the banks of RAM would be addressed and any point in time.

4.04V sounds low though.

Also, it depends on whether they modified the MPU board by cutting and rewiring the power inputs or if they rewired the wiring harness. If the later than your unmodified board will not run in that system.

ken
 
... but I thought that a 4164 chip upgrade got rid of the 5 Volts ..

it removes the need for the minus 5 volt and +12v rails that 4116 chips need.

but also as ken said obviates the need to replace the -5v and +12v rails to the ics with 5v to lock in the ram page. see the links below re the power supply adapters.
 
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...4.04V sounds low though...

1) I tested the Power to the RAMs in my working cocktail game table. They all have RAM chips that are upgraded to 41256 chips, and pins 1, 8 and 9 are all at 4.04 Volts??? (seems weird). It works fine in the upright machine without any problems.


the 5volt rail at the +5v pin of ttl ics must be in the range 4.75v to 5.25v
if it is outside that range, all those ttl chips will not operate as designed.

too high and they may fry. too low, and no work bro. :D
 
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and lastly, although the data sheets for the rams (4116, 4164, 41256) may indicate a wider tolerance on the 5v rail (5v +/- 10%) ttl ics whereas have a much smaller tolerance (5v +/- 5%) so it is critical to get the power supply right.
 
the 5volt rail at the +5v pin of ttl ics must be in the range 4.75v to 5.25v
if it is outside that range, all those ttl chips will not operate as designed.

too high and they may fry. too low, and no work bro. :D

Pardon Me for dropping in in here but i had to state something..ALL TTL LOGIC CHIPS no matter what they are..UNLESS otherwise Stated From the MFG...should be NO HIGHER than +5.15 Volts DC Underload,,,and i don't care who says otherwise..most eletronics schools teach this..NOW that doesn't mean it should be higher..but to be safe..set yer +5 volts on yer PS to +5.15Vdc and then see if yer logics start working..if not check for HOT chips that got shorted from overvoltage :)


Good Luck.

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Daniel.
 
Thanks for all the good information. I will be cleaning and checking the output voltages of the Power Supply and hopefully make it more reliable.

As much as I am trying to keep these Defender machines original, I thought I would order a switching Power Supply that has a variable adjustment on the 5 Volt setting that I can use for testing purposes. Knowing that I have a good working transformer in my upright Defender Cabinet, what switcher would you recommend that I could buy that has variable adjustment on the 5 Volt supply? I would like to get one ordered.

Also, I believe my Logic Probe will be here on Friday.
 
Pardon Me for dropping in in here but i had to state something..ALL TTL LOGIC CHIPS no matter what they are..UNLESS otherwise Stated From the MFG...should be NO HIGHER than +5.15 Volts DC Underload,,,and i don't care who says otherwise..most eletronics schools teach this..NOW that doesn't mean it should be higher..but to be safe..set yer +5 volts on yer PS to +5.15Vdc and then see if yer logics start working..if not check for HOT chips that got shorted from overvoltage :)


Good Luck.

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Daniel.

i rely on mfr datasheets myself for species and work to the median in the range myself. interested in any empirical method to the rationale for the 5.15v (or is it a rule of thumb ?)
 
Yellowdog, Andy, and others are definitely the masters of DEFENDER problems(thanks and we appreciate you guys)

I have found that almost every Defender I have dealt with it has had a POWER SUPPLY problem and has needed to be REBUILT (not just with a Band Aid either), connectors to and from the PS , CPU, ROM, and SOUND board should be repined. I would START here and focus on building that "Foundation" of a good power supply. you can have everything else be perfect and NO GAME because of "flaky" power.

AFTER you know you have a SOLID "Foundation" of power then I would follow the flowchart from the theory of operations.

As far as a logic probe. I use a cheap Radio Shack one. I would love to find and use a better one if anyone has any recommedations .
 
i rely on mfr datasheets myself for species and work to the median in the range myself. interested in any empirical method to the rationale for the 5.15v (or is it a rule of thumb ?)

interested in any empirical method to the rationale for the 5.15v (or is it a rule of thumb ?)

allow me to explain...in 1981 i went to work at mardi gras Fun Center...as an attendant..the Head Tech Was a Man named Walter Horn (RIP) who had worked in the amusement industry for over 30yrs and worked for BOTH major distributors in the USA - Birmingham vending and Brady Dist.. so with that experience behind him..he went from working for them to working in this arcade ..so when i started working there he noticed i was good at repair and took me under his wing and taught me just about everything he knew he could teach..and his first rule was - On ANY power supply in ANY game...the 5 volts should ALWAYS be set to at Least +5.15 vdc no matter what the manual tells you..because over time resistance builds up in wires and connectors and the voltage drops will happen and all TTL logic usually runs on +5 volts..so to him and me and about 20,000 other techs in the amusement industry will tell youi that setting yer power supply to +5.15 is usually a rule of thumb from Experience from people who been doing it longer than most of us doing it now...i was Fortunate to be taught by the nicest man on the planet who took the time to make sure all of us guys in the arcade KNEW why we do what we do repairing arcade games... so do we follow what the manual says..Of Course..it it always right... HELL NO...but if you've been doing repair work for many years..you Learn what Actually Works and what a Engineer Thought Would Work... so as Walt (may He Rest In Eternal Beautiful Sleep) used to tell me.."NOTHING ever is What Is Printed..and You Can't Make Chicken Soup out of Chicken SHit... Check It.. Fix It And Check It Again..and if that Don't Work..Someone Screwed Up The paperwork... So FIx It..thats Why Your Here" :D

so thats the Best Answer I Got..it's how i Was Taught..even tho electronics School used to Say Otherwise :)

i Use My Gut..it's usually right when everything Says Otherwise..thats what Walt Wanted me To Learn..and I Did ! Thank You Walt! :)


Thats All I Got :)


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Daniel.
 
hey, you got plenty there daniel! thanks for the long winded explanation. useful tips in there for sure! around 5.1 has been a pretty good rule of thumb for defender /williams stuff based on practical considerations such as you have set out above. :D:D:D
 
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