Mortal Kombat 1 Joystick issue/ Sound issue

[Broodwich]

that's ok, i'm still learning also, past the basic stuff like checking voltage and connections i'm a "nooby noob" also

i was going to ask if you'd played with both next so you answered that question (the one mounted to the coin door is the main volume control for the cab, the one connected to your board is one that might have been added later or might be the dedicated original (can't tell without seeing the wiring to them)

test the one that's directly connected to the board, it should say 50k or something ink stamped on the back, grab your volt meter and with the game off and meter set to resistance/ohm's check the 2 tabs that have a wire soldered to them when you turn the knob the resistance should change but should either bottom out or max out at 50k ( or whatever was stamped on the back).

if you can borrow/find a good working board (any jamma game with working sound) plug it in and that will tell you if it's your cab wiring or speakers. if everything works and you get sound then yea there's definitely a problem with your boardset.

 

[Cloverdragger]

that's ok, i'm still learning also, past the basic stuff like checking voltage and connections i'm a "nooby noob" also

i was going to ask if you'd played with both next so you answered that question (the one mounted to the coin door is the main volume control for the cab, the one connected to your board is one that might have been added later or might be the dedicated original (can't tell without seeing the wiring to them)

test the one that's directly connected to the board, it should say 50k or something ink stamped on the back, grab your volt meter and with the game off and meter set to resistance/ohm's check the 2 tabs that have a wire soldered to them when you turn the knob the resistance should change but should either bottom out or max out at 50k ( or whatever was stamped on the back).

if you can borrow/find a good working board (any jamma game with working sound) plug it in and that will tell you if it's your cab wiring or speakers. if everything works and you get sound then yea there's definitely a problem with your boardset.

Sweet!! Thanks for all the input, I now have something to do this weekend! haha!

 

[action76]

I assume you are not getting a bong when first powered on? When turned on are you getting any speaker hum or buzz? You may have to turn the pot all the way up to hear but if you get any noise like a hiss from the speakers then your amp circuit is good on the board. If you are getting nothing, the amp may need replacing. It is not uncommon for them to go out as I understand.

 

[mecha]

the pot attached to the sound board is what completes the sound circuit coming off the board. which is why if no sound pot is present the game won't play sound.

the cabinet sound pot... you could eliminate that entirely if you intend on keeping MK1 installed. you could eliminate it anyway, as you'll always have the ability to adjust the volume on games be it through an external pot like MK1, or a dial pot on the board, or the game has digital volume setting (like MK2). not like it's hard to get at the game board since you have that cool shelf.

you could very well just have a wire break going to the cabinet pot, or from the cabinet pot to the speaker. or the cabinet pot can be bad. I'm thinking you can just cut the wires off the cabinet pot and just splice them together to get sound, right?

if you have 8 ohm speakers (or maybe it's just 1 right?), meter on a low resistance setting, I forget what the lowest is, like 100 ohm? if you get about 7.8 ohm then the speaker's good.

if you eliminate the cabinet pot and get amplifier hiss then you're doing good. get the BONG (or actually it sounds more like a DUUUUUUUUURN lol) then you're really good.

I can't remember off hand and can't tell from the pics, but your ribbon cable you definitely want the red striped end facing the pins on the headers labeled 1-2 (it'll look like a vertical 12) just to ensure that's not connected backwards on one of the sides.

that's about all I can think of to try for now.

 

[Cloverdragger]

the pot attached to the sound board is what completes the sound circuit coming off the board. which is why if no sound pot is present the game won't play sound.

the cabinet sound pot... you could eliminate that entirely if you intend on keeping MK1 installed. you could eliminate it anyway, as you'll always have the ability to adjust the volume on games be it through an external pot like MK1, or a dial pot on the board, or the game has digital volume setting (like MK2). not like it's hard to get at the game board since you have that cool shelf.

you could very well just have a wire break going to the cabinet pot, or from the cabinet pot to the speaker. or the cabinet pot can be bad. I'm thinking you can just cut the wires off the cabinet pot and just splice them together to get sound, right?

if you have 8 ohm speakers (or maybe it's just 1 right?), meter on a low resistance setting, I forget what the lowest is, like 100 ohm? if you get about 7.8 ohm then the speaker's good.

if you eliminate the cabinet pot and get amplifier hiss then you're doing good. get the BONG (or actually it sounds more like a DUUUUUUUUURN lol) then you're really good.

I can't remember off hand and can't tell from the pics, but your ribbon cable you definitely want the red striped end facing the pins on the headers labeled 1-2 (it'll look like a vertical 12) just to ensure that's not connected backwards on one of the sides.

that's about all I can think of to try for now.

Very nice diagnostics!! I will try and cut the cabinet pot wires and splicing them together. Just to see what it does. My Midway T2 Judgment day did the DUUUUUUURN when it started up, so I know what it sounds like, HAHA.

Ribbon is on right, with the red strip toward the 1/2 on the board. I was thinking of replacing the ribbon just to rule it out.

I'll try some of this tomorrow! THANKS!!

 

[Broodwich]

mecha mentioned in another post that you can use a computer IDE cable; would be worth trying untill you can get a replacement.

if it turns out being bad i have a few originals and i'm waiting on some 18" ones to arrive.

 

[Cloverdragger]

mecha mentioned in another post that you can use a computer IDE cable; would be worth trying untill you can get a replacement.

if it turns out being bad i have a few originals and i'm waiting on some 18" ones to arrive.

I"m not sure if I cheated or not, but I found a board on Ebay for 15.00. I bought it. haha, But i'm still going to try to trouble shoot tomorrow.

 

[Broodwich]

I"m not sure if I cheated or not, but I found a board on Ebay for 15.00. I bought it. haha, But i'm still going to try to trouble shoot tomorrow.

soundboard? or complete set? always good to have a spare imo, good price either way also.

 

[Cloverdragger]

soundboard? or complete set? always good to have a spare imo, good price either way also.

Just the sound board with new ribbon cable. I want to start practicing on how to recap boards too by unsoldering them and such, so extra boards will be good.


I saw on ebay another MK1 board for sale, and he noted that you have to have the pot for the cpu board sound. It looked like in his picture, he mounted the pot right on the board itself. Thought that was kind of cool.

""All Mortal Kombat 1 boards REQUIRE a volume pot (Potentiometer). Its a little knob that controls the volume. With out it, you will NOT have any sound. This does NOT come with the game... However, mine DOES ! I have soldered it to the sound board as seen above, so you dont have to worry about it.""


http://cgi.ebay.com/Mortal-Kombat-J...ltDomain_0&hash=item4aaa4fe4de#ht_1539wt_1242

 

[Cloverdragger]

I got my new sound board, and....


It did NOT fix the problem. So it has to be a wiring/speaker issue.


One of my pots has 3 wires, and the other one only has 2. Not sure if that is anything.

The owners manual i downloaded says ...

NO SOUND = Check the speaker and speaker connection to pins L and 10 on the JAMMA Connector. Check for +12 V dc at pins F and 6 on the jamma connector. Check inter-board wiring from CPU board to the Sound Board.


I have no clue where those pins are on the JAMMA connector, as this manual does not state location/wiring colors.


The speaker is also in bad shape so I want to replace it. It has 2 mounting holes in the cabinet but only had 1 speaker. There wiring up there has 2 wires coming in, Yellow/green and white, and jumper wires from those wires to go to a second speaker. The 1 speaker that is up there is 8 OHM and my manual does not say anything about what size speaker is suppose to be used.

IF i'm suppose to have 2 8 OHM speakers instead of 1 8OHM speaker, would that mess with anything?


Thanks in advance!!

 

[action76]

If using the three lead POT one wire has to be on the center lead and the other can be on either left or right lead (This just determines if clockwise or counter-clockwise is increasing). I am not sure about the two lead. I guess it only functions in one direction.

There should be a Jamma chart in the manual but I attached one and a pic in case it doesn't.

One of may cabinets has only one 8 ohm speaker but has a hole and wired for two and it works fine. If you want to test that speaker, take it out of the cab and if you have a stereo system that has separate speakers attached to the amp with two wires (usually black and red). Unhook the wires from the stereo speaker and attach or hold them on the two speaker leads, turn on some music (low volume at first anyway) and see if you are getting anything out of the speaker.

Hope this helps.

 

[Cloverdragger]

Thanks so much for those attached pics and info!

I just tested the speaker to the 8ohm rear speaker of my saround sound set up, and NO SOUND! But then i took my saround sound speaker and tested it in the arcade with no results. So i need a new speaker for the arcade reguardless, then my search continues!

 

[Cloverdragger]

SOUND FIXED!! the sound pot on the sound board was only going between 50K and 15K, still to much resistance to let sound out. We dropped a 5k on it (only thing Steve had) and SOUND IS ON!! It really needs a 15K sound pot, as 5K is not enough resistance to kill it down to nothing, but with the sound pot on the cabinet, it goes down pretty low.


Thanks everyone, I learned how to properly test sound pots now!! (I obviously didn't do it right the first time!)

 

[Broodwich]

i f'n knew it!

that's ok, i'm still learning also, past the basic stuff like checking voltage and connections i'm a "nooby noob" also

i was going to ask if you'd played with both next so you answered that question (the one mounted to the coin door is the main volume control for the cab, the one connected to your board is one that might have been added later or might be the dedicated original (can't tell without seeing the wiring to them)

test the one that's directly connected to the board, it should say 50k or something ink stamped on the back, grab your volt meter and with the game off and meter set to resistance/ohm's check the 2 tabs that have a wire soldered to them when you turn the knob the resistance should change but should either bottom out or max out at 50k ( or whatever was stamped on the back).

if you can borrow/find a good working board (any jamma game with working sound) plug it in and that will tell you if it's your cab wiring or speakers. if everything works and you get sound then yea there's definitely a problem with your boardset.

Glad it's all fixed

btw i uploaded new MK1,MK3, and NBA Jam Manuals to the Manual Archive.

 

[action76]

Glad you got it going!

 

[Cloverdragger]

Glad you got it going!

Me too! Its much more fun to hear FINISH HIM! HAHA!!

My MK2 board should be here monday, so I can play with that can of worms next!

 

[modessitt]

btw i uploaded new MK1,MK3, and NBA Jam Manuals to the Manual Archive.

I gave him hard copy manuals of MK1, MK1 Kit, MK2, and MK2 kit when he was here. I have a whole box of them...

 

[Broodwich]

I gave him hard copy manuals of MK1, MK1 Kit, MK2, and MK2 kit when he was here. I have a whole box of them...

nice, i just picked up a MK1 cab last weekend and noticed the museum didn't have them uploaded. I have plenty of MK3 Kit Manuals (and a non kit manual) but i didn't have MK1/nba jam.

Glad you guys were able to figure out the volume pot issue on the OP's machine.

 

[modessitt]

Well, I have a bunch of MK3, MK3 kit, NBA JAM and NBA JAM kit manuals too, as well as at least one T-Unit manual. I had a bulk buy that came with a bunch of manuals, including about 75 MK manuals of various versions and about 25 NBA JAM manuals...

 

[Broodwich]

sweet jesus, remind me to buy a couple off you (i like to have original hard copies) that is if your selling.