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Problem with all my Data East PCBs (loud beeping sound)

Catoblepa

Catoblepa

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Here's a real head-scratcher... hope someone can help me - or just point me in the right direction, 'cause I couldn't find any info! ;(

I've recently bought three Data East PCBs from an arcade operator (Funky Jet, Double Wings and Pocket Gal Deluxe); then I've bought a fourth Data East PCB from another operator (Crude Busters).
They all seem to work fine, BUT after, more or less, a minute in attract mode or gameplay, an incredibly loud beep starts blasting from the speakers. It's completely independent from the volume knob, it starts slower and gets faster, like some kind of warning.
Here's a short video (sorry for the shaky camera):

https://drive.google.com/file/d/1yQlefPlbwt5ZTnNL_HvNT2KdDLah2scb/view?usp=sharing

As you can see, the video part is absolutely fine:



The only other worrying sign is that this FUJI MB3730A (audio power amplifier) becomes extremely hot, very fast - so hot you can smell it.



Aside from that, the games are fine, audio and video are perfect... so could it be an overheating alarm?

It's very strange that all my Data East PCBs have this problem, and they all overheat; maybe I'm doing something wrong with my Mak Strike Supergun? My other PCBs are working fine.

Thanks a lot in advance!
 
Have you measured your 12V rail?
How do you set the volume pots on your PCBs?
 
I've set the volume pot very low, but the beeping sound doesn't change, it's always at max.

Didn't measure the 12V rail yet, do you think it could be the PSU?
 
I'll do some test as soon as I can, thanks Apocalypse. If anybody has experienced this problem with Data East boards, please let me know! I can't be the only one ^_^
 
Try the pcb's in a standard jamma cab if you have the means.
I read this supergun has some kind of audio attenuator, that could be the problem.

Had kind of the same problem in my jamma cab... burning hot amplifiers and strange sounds.... turns out my speaker was blown, reading only1,5 ohms.
 
Could you take a still shot of the wiring? Psu to supergun especially. Also the video seemed to show 4.8x on the 5v line so you should measure and adjust that too so it’s 5v under load. Use a multimeter, I wouldn’t trust that little readout on the Mak until you verify it.
 
Trol said:
Try the pcb's in a standard jamma cab if you have the means.
I read this supergun has some kind of audio attenuator, that could be the problem.

Had kind of the same problem in my jamma cab... burning hot amplifiers and strange sounds.... turns out my speaker was blown, reading only1,5 ohms.
Click to expand...
I have two cabs, one has no jamma audio (I'm using the MVS stereo headphone connector), the other has no video (monitor is gone)... well, I'll try the PCB on the one with no video and see if the buzzing sounds start again ;)
ekorz said:
Could you take a still shot of the wiring? Psu to supergun especially. Also the video seemed to show 4.8x on the 5v line so you should measure and adjust that too so it’s 5v under load. Use a multimeter, I wouldn’t trust that little readout on the Mak until you verify it.
Click to expand...
Sure! The problem occurred even with a perfect 5.00, but I'll take a shot of the wiring; of course if something was wrong with the wiring, my other boards wouldn't work correctly, but they're all fine except the Data East ones... it's really strange. Thanks for the help, I'll be back with pics
 
is your MAK supergun set to mono or stereo mode ?
If it is set to stereo, that might explain why the MB3730A is getting very hot.
The switch should be set to mono for these games.
 
sylphia said:
is your MAK supergun set to mono or stereo mode ?
If it is set to stereo, that might explain why the MB3730A is getting very hot.
The switch should be set to mono for these games.
Click to expand...
Thanks, I'll also check that!
 
Just a quick update... I've tried setting the MAK switch to mono, but I still hear the loud beeps after a while. Tomorrow I'll test the Data East boards in another cab and take a shot of the psu to supergun wiring;
by the way, I've bought more boards from an arcade operator and today I got the same loud beep problem, but this time with a Taito board. Now I can tell it's clearly a supergun related problem... I just wish I knew what the heck IS the problem.
 
Mak strikes again. Did you ask them for support? Maybe it’s an alarm the supergun is generating.
 
ekorz said:
Mak strikes again. Did you ask them for support? Maybe it’s an alarm the supergun is generating.
Click to expand...
You're right, that's exactly what I'll do... wish the HAS supergun was available when I needed it, the MAK was just a stopgap for me :( (is it back in stock? I'm afraid not, but I'll have to check RGB's thread)
 
So, I've just tried that same Double Wings PCB on my cab with the faulty monitor (but working audio): no loud beeps at all, even after quite a long wait. MB3730A gets hot, but I think it's supposed to get hot (I couldn't tell if it was a bit cooler this time, but it didn't smell that bad, so... who knows?). Anyway, the MAK supergun seems to be the culprit here...

As ekorz required, here's some pics of the Psu wiring:



 
Your ground wire looks very undersized to me. It's half the size of your +5 and +12 and definitely won't be helping your issue.

Have you used a multimeter on the PSU or on the board to measure your +5 and +12?
 
amplifiers always get warm.
If you can touch it and can hold on, its ok.
If it burns your fingers, its not ok.
My bet is the speaker connections/circuit on the supergun.
 
I'm sorry for bein' so slow with updates, but work is keepin' me so busy I can't always go to the mancave and test things...

In the meantime, I'd like to thank all you guys who are helping me with questions and suggestions, you're all very kind. Hope I'll get to the bottom of this (and I hope I won't have to buy a different supergun)!
 
UPDATE

Well, instead of goin' insane trying to figure out why the MAK Strike was behaving like that ('cause it just had to be a supergun problem), I simply decided to buy a HAS 4.1 Supergun from Mike.
It arrived a few days ago, today I finally had time to wire it; I've tested my Double Wings PCB and... no beeping sound, everything's perfect. Even after ten, twenty minutes, the FUJI MB3730A audio power amplifier is warm, but I can keep my finger on it. So, I'll probably never know what it was and why it only happened with Data East PCBs, but I surely know the HAS is an excellent purchase. Thanks again to all the people that helped!
 
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