Gottlieb Solved Mars God of War (Gottlieb, 1981) problems

[Gr8snook09]

Hello. I recently bought a neglected Mars God of War. When I got it nothing worked except the score displays lit up. After simple cleaning and checking connectors everything worked! Sound, speech, scoring, flippers and pop bumpers...everything. It was all scoring correctly as well. Recently out of the blue all of the non solenoid related switches that are behind playfield rubbers quit working or generating sound. All other switches work and score fine. Then today the speech is slow and all other sounds are barely audible no matter what the pot settings are. The only thing I did today was replace the Orange cap in the bottom of the cabinet. I'm brand new to system 80 pins so I'm pretty clueless. Any ideas ?? Oh. I did a speech test and it ran through everything and at the end it kept saying "sixteen". Also did a system test via the coin door and it brought up "5101" in the player one display. Thanks guys !

 

[pinballdaveh]

the 5101 code is usually a battery failure code or the 5101 chip might be bad. does the CPU have its orig. battery still installed on the board? does the CPU board have any battery leakage damage? if it has a remote battery pack , have you changed the batteries yet? batteries that are almost dead will cause all kinds of problems.

 

[Gr8snook09]

the 5101 code is usually a battery failure code or the 5101 chip might be bad. does the CPU have its orig. battery still installed on the board? does the CPU board have any battery leakage damage? if it has a remote battery pack , have you changed the batteries yet? batteries that are almost dead will cause all kinds of problems.

It has a memory capacitor installed. No battery damage that I can see.

 

[Gr8snook09]

Fixed the switches. One was bent shut. I guess I bent it installing the rubbers. Now I just have the speech issue. Could the 5101 be due to the memory cap install ? It used to have a white nicad battery there.

 

[pinballdaveh]

if the CPU had a 5101 it would be a ram memory. the memory cap when charged will hold data in the CPU for 8 days. so is the cap charged? keep the machine on a few hours and check for code. the sound speech problem might be in op amp speaker driver section. the coupling cap and the caps around the op amp may be bad. sorry i dont have a schematic on that board.

 

[Gr8snook09]

Is the sound speech board you are talking about the old woody one in the lower cabinet ??

 

[pinballdaveh]

no , old woody is the sound speech power supply , but changing that large blue filter cap would be a good idea. the sound speech board is in the head lower left. i see that there is a volume control in side the cabinet , is there also a volume control on the sound speech board? if you have the manual/schematics , the op amp in the schematic will be shown as a sideways triangle. the small caps and the volume pot should be in that area. posting a partial pic of that area of the schematic would help. knowing to change the orange cap was helpfull. if ground mods were not done yet , pinwiki gottlieb system 80 will explain them.

 

[Gr8snook09]

There are actually 5 adjustable pots on the sound board. 2 at the top right (R15 & R16) and there are 3 in the very lower right corner (R6, R9 and R13). On the schematic R15 and R16 are listed as Volume, R6 is listed as Freq. Adjust. R13 is listed as Amplitude Adj. R9 is listed as 2.2k ?? On the schematic R9 is smaller and horizontal compared to R6 and R13 which are larger and vertical. On the physical board all 3 are the same vertical grey rectangular with a brass adjustment screw in the bottom of each.

 

[Gr8snook09]

Mine is exactly the one in your thumbnail.

 

[pinballdaveh]

the 3 pots on the lower right should be 10 turn precision pots and usually are factory set. the 2 stand up pots are speech and sound pots and can be adjusted. the caps in the paint circles are the most likely to be bad. the pot inside the cabinet are known to go bad. if there is a sound / speech test as part of self test, put the machine in that and try turning and wiggling that cabinet pot shaft. is there a test switch on the sound/speech board?

 

[Gr8snook09]

Got all the speech working. One of the dip switches wasn't all the way engaged. Now I'm down to just the sound effects being barely a whisper !

 

[Gr8snook09]

I did a speech test (see my first post) when it was done it kept saying "sixteen"

 

[pinballdaveh]

since the speech is back can its volume be adjusted by the speech pot and the cabinet pot? have you tried measuring the resistance of the speech and sound pots? have you tried pushing down or re-seating of the socketted chips?

 

[Gr8snook09]

Yes volume can be controlled by both. I have not measured the resistance. My MM is MIA ! I have pushed down the socketed chips. All the scoring/gameplay sounds are correct and going off at the correct times. They just can't be heard unless you are right on top of the game and the volume is all the way up. Then they are just a whisper. Except the speech is fine. (Now)

And what does "sixteen" mean at the end of the self test? That is the problem maybe??

 

[pinballdaveh]

what does MM mean? does the machine display 16 or say sixteen? is it at the end of the coin door self test or the sound board self test. if its the sound board self test , my system 80 service manual doesnt have any info on sound board fault codes. it does say to check control board option switches S25,S26, and S27 for proper setting. also check voltages +5VDC, +12VDC, and -12VDC on sound board. does your manual say what the 8 switches on the sound board do?

 

[Gr8snook09]

MM means multimeter. It says sixteen after the soundboard test, not coin door. S25,26,27 are set correctly to the on position, the soundboard 8 switches are all set correctly. And it says that if A6J2 -2 is jumpered to the ground then it will say "sixteen".

 

[pinballdaveh]

thank you for posting that sound test chart. that and some help from pinwiki i might have the answer. on the bottom of the chart by grounding certain data lines will give a sound responce, like the sixteen that it keeps saying. the voice data lines from the S&S board come from the driver board. on the driver board sounds 1,2 ,4, and 8 come from Z13 and out thru J5 pins 1,5,6, and 7. sound 16 is driven by Q10 and out thru J2 pin 9. if Q10 is shorted sound 16 will always show as shorted. Q10 is a mps-a13 availible from marco. replacing Q10 sounds like the next thing to try.

 

[Gr8snook09]

Geez. I wish I was smart enough to figure that route. Not a chance! Lol. Is there a way to test it to see if it's bad?

 

[pinballdaveh]

yes but your MM is MIA!!

 

[Gr8snook09]

I left it at my warehouse. There are a couple in there. But it's 35 minutes away. I'll have to go grab one tomorrow morning.

 

[Gr8snook09]

Ha! I found one in my closet. Thought I saw it somewhere around here. Tough getting old!

 

[pinballdaveh]

to properly test transistors they should be tested out of circuit. you will need a 25 or 30 watt soldering iron and de-soldering wick or braid.

 

[pinballdaveh]

since you are looking for a shorted transistor you can test it in circuit. set your MM for a resistance Rx1 setting and put the test leads on two transistor wires , then change the leads to different wire combinations. a zero resistance reading is any combination is a shorted transistor. if your MM has a diode beeb setting that could be used also. a beeb sound is usually a short. a good transistor will have 2 low resistance readings (called junctions) in 2 different test lead combinations. you can also check your readings against the same kind of transistor next to it.

 

[Gr8snook09]

I'll try it! Thanks !