Donkey Kong PCB cap kit? (audio hum and siren noise)

[VWbus]

Does anyone sell a 2-stack PCB cap kit? Long story short, I'm having audio issues with my DK and I believe to have narrowed it down to the audio caps on the PCB itself.

If anyone doesn't sell the kit, then perhaps Ian Kellogg could sell me the caps I would need?  

[iankellogg]

I never bothered to make akit. Its on my list now anyways. Should be up soon.

[iankellogg]

I Don't own a donkey kong PCB at this time so I don't know for sure which caps are what.
I think I have identified everything for the audio section
The rest of the caps on the board I am unsure of.
I think the axials on the board are
470uF
220uF
100uF
and maybe 47uf or 33uF?

I only need to find out what caps are axial and I am ready to put this on the website.

[iankellogg]

Here is the audio only section of caps
https://iankellogg.com/index.php?main_page=product_info&cPath=23_49_37&products_id=161

[VWbus]

Wow! Ian, you are a Rockstar!

I'm going to order these right up.

I've tried everything to fix this audio problem I'm having. Here is what I've done so far:

1. Completely replaced the audio amp with a reproduction audio amp from Twisty Wrist Arcade

2. Replaced all the 2SC 1815 transistors near the audio portion of the pcb. 6 of them. Q1 through Q6

3. Swaped out my speaker for a reproduction speaker from MikesArcade

My only 2 options left are using the PCB audio cap kit you just created and maybe even re-capping the power supply. What do you think?

There is a YouTube clip of the buzzing sound mixed with that annoying "siren" sound that just repeats:

http://www.youtube.com/watch?v=dPQKSIgcQfY

I've heard that buzzing sound might be normal but for me it seems loud. And I know that siren or "wah-wah-wah" sound is not normal.

[iankellogg]

well the first thing would be the caps as thats a common failure point but it almost sounds like it isn't turning off one of the audio generators.

[VWbus]

but it almost sounds like it isn't turning off one of the audio generators.

That's what I thought too. Apparently, the transistors were supposed to solve that problem. However, I only replaced Q4 and Q6 so far. (I wanted to tell if that fixed it)

So last night I replaced the rest of the transistors but have not officially tested it yet. We will see.

I also have a spare DK jr board arriving soon. I'll put that in and see if that board also has the buzz sound. Thanks again for your help!

[VWbus]

Thanks Ian!

I just bought a power supply cap kit and DK PCB audio kit from you. I'll report back with my results!

One more update:

I don't know why this never occurred to me, but I turned on my DK cab without the PCB inside...and it STILL made the loud hum. That sounds like a a problem with the power supply no?

[iankellogg]

If the game PCB wasn't there and its humming then it could be from the amp.

I have been trying to get my hands on a nintendo that hums badly so I can document the issue.

If you haven't replaced your b+ cap on your sanyo, you should do so.
My current belief is it has something to do with the lack of grounding on the speakers and the input wire.
Try disconnecting the audio input wire from the audio amp. M ake sure there are grounding wires from the monitor and I think even the speakers should have grounding wires. 100% make sure you have a ground prong on the plug and it is VERIFIED to be connected to the monitor. This is a switching power supply. Ground is even more important here than it is with a linear power supply.

[VWbus]

If the game PCB wasn't there and its humming then it could be from the amp.

I have been trying to get my hands on a nintendo that hums badly so I can document the issue.

If you haven't replaced your b+ cap on your sanyo, you should do so.
My current belief is it has something to do with the lack of grounding on the speakers and the input wire.
Try disconnecting the audio input wire from the audio amp. M ake sure there are grounding wires from the monitor and I think even the speakers should have grounding wires. 100% make sure you have a ground prong on the plug and it is VERIFIED to be connected to the monitor. This is a switching power supply. Ground is even more important here than it is with a linear power supply.

This is very good feedback Ian thank you so much. I used one of your Sanyo Kits and completely re-capped the monitor including the B+ cap. The picture looks fantastic now.

I know the speaker itself has a ground wire. However, come to think of it, I'm not sure the monitor frame is grounded? The power plug for the monitor is only 2 pronged going into that outlet plug in the bottom of the cab.

When I first got the machine, the main power cord was missing a ground prong but I have already since rebuilt that with a brand new power cord.

If my new power supply cap kit doesn't help, then it's got to be a bad ground somewhere. I'm glad to cap the power supply though. I bet it has never been touched and at least I'll have some insurance.

I'll keep you posted!

[VWbus]

My sweet cap kits arrived. One kit is for the audio capacitors on the DK PCB and the other kit is the capacitors for a DK power supply. I just really love how organized your kits are Ian!





I decided to do the audio PCB capacitors first. In the image below, I have now replaced every single audio capacitor and transistor inside the red line. 16 caps and 7 transistors I believe



I then hooked the board back up into my DK, turned it on and....I STILL have that annoying hum mixed with the siren sound in the background. Sigh. The overall sound of the game might be sliiiighly better. But maybe my ears are just playing tricks on me now. Good news is that I didn't make it worse...but I certainly didn't outright fix it.

The last place I have not really poked around is the power supply. So, I'll be putting a new cap kit in the power supply next. Might as well, its 35 years old and has never been capped.

[iankellogg]

Glad you like the kits. I still think there is something that is turning on some kind of sound generator that shouldn't be on. I really wish I could help further. I just have no experience with Dk

[VWbus]

No worries whatsoever Ian! You've already been more than helpful. I think you're right. Something is not cutting off the sound and that is the siren noise. And the hum is probably a bad ground.

I'm gonna cap that power supply and go from there.

[VWbus]

Hi Ian,

I'm about to cap my DK power supply and I was just checking out all the cap locations. I noticed that C2 on the board doesn't look like a cap. (See image below) Is that where I should really install the new C2 cap?

[iankellogg]

Is there one PCB or two PCBs in the supply? I vaguely remember there being 2 PCBs. Check the other one.

I actually found  my copy of the manual and it has a cap map in it. I have never seen this published online so I will be scanning it in this week and fixing the instructions for that kit.