Hello everyone, I'm quite lost on how to fix this predicament. I have got some sort of interference in the picture for this monitor, and I've been struggling to figure out what it is.
Here's a video of said interference.
What I've done: cap kit, minus 3 of the 100uf 35v capacitors, as I did not have them. This includes the filter.
Replaced the HOT
What I've looked into:
Confirm the PSU GND and Video GND are connected - they are via game PCBs.
Sync trace is intact, but solder mask is damaged. Continuity check between solder joints measured ~0.8-1.0 ohms.
Chassis should not be connected to earth ground as the New Astro City diagram does not call for E.G. to the frame of the monitor.
I am not using an isolation transformer.
I have not done the G1 voltage mod (yet), so there is a jumper connecting the G1 to ground. Read more about it here.
B+ is a perfect 76v.
There may be other things I may be forgetting, but I hope that helps with finding out my issue. The next steps I am about to take (when I can) is installing those last three caps, and then scoping the PSU circuit.
Thank you for any help!
Nanao MS9-29A Video Interference
- zed7
- Please Continue...
- Posts: 7
- Joined: September 19th, 2021, 1:18 am
- Location: Canada
- eBay: zed7-82
- Initials: zed
Nanao MS9-29A Video Interference
Tecmo New Astro City
-
- Please Continue...
- Posts: 27
- Joined: May 2nd, 2020, 6:46 pm
- Location: United States
- eBay: ericthegreat777
- Initials: ECM
Re: Nanao MS9-29A Video Interference
I had same issue but filter cap fixed it, I would be willing to bet it is those missing caps if they are some of the larger ones.
- zed7
- Please Continue...
- Posts: 7
- Joined: September 19th, 2021, 1:18 am
- Location: Canada
- eBay: zed7-82
- Initials: zed
Re: Nanao MS9-29A Video Interference
They're one tenth the size of the filter, so it is unlikely they will fix the issue; however, I do intend to replace them first before going more extensive routes to fix the monitor
Tecmo New Astro City
- grantspain
- Tech Head
- Posts: 4823
- Joined: August 17th, 2008, 4:23 pm
- Location: down south
Re: Nanao MS9-29A Video Interference
the 100uf 35v caps are critical in the vertical circuit so when you get a chance replace them
that wave going through the screen looks to be external, earth/ ground problem, dirty power source, interference in signal from game board, +5 far too high on power supply
if it were degauss or filter cap fault it would be more pronounced
that wave going through the screen looks to be external, earth/ ground problem, dirty power source, interference in signal from game board, +5 far too high on power supply
if it were degauss or filter cap fault it would be more pronounced
- zed7
- Please Continue...
- Posts: 7
- Joined: September 19th, 2021, 1:18 am
- Location: Canada
- eBay: zed7-82
- Initials: zed
Re: Nanao MS9-29A Video Interference
Thank you for giving me this input, I should have the caps within 2 weeks. I believe I have had the 5v set to 5.1v on the power supply, so that may be an issue?grantspain wrote: ↑October 15th, 2021, 5:42 am the 100uf 35v caps are critical in the vertical circuit so when you get a chance replace them
that wave going through the screen looks to be external, earth/ ground problem, dirty power source, interference in signal from game board, +5 far too high on power supply
if it were degauss or filter cap fault it would be more pronounced
I confirmed that the tube does not go to earth ground in any way, so that should be fine. My Prof at school believes a regulator in the power supply circuit for the monitor may be the issue, which after caps, I intend to scope the monitor to see if I can find where the frequency is being let in.
Tecmo New Astro City
- grantspain
- Tech Head
- Posts: 4823
- Joined: August 17th, 2008, 4:23 pm
- Location: down south
Re: Nanao MS9-29A Video Interference
if the reg was bad the b+ would not be stable at 74-76vdc
- zed7
- Please Continue...
- Posts: 7
- Joined: September 19th, 2021, 1:18 am
- Location: Canada
- eBay: zed7-82
- Initials: zed
Re: Nanao MS9-29A Video Interference
Well... the monitor stopped working. I replaced the caps first to see if that was the issue, it was not.
Confirmed both MOSFETs I have should be fine, and not the issue either. Monitor stays in HV Shutdown and will chirp or click 1 or 2 minutes after turning off. The B+ seems to surge to 100VDC+ and then immediately lowers back down to around 30V or less. I suppose something in the primary PSU circuit was on its way out, letting AC ripple in, causing the interference. I'm not too sure where to start.
Confirmed both MOSFETs I have should be fine, and not the issue either. Monitor stays in HV Shutdown and will chirp or click 1 or 2 minutes after turning off. The B+ seems to surge to 100VDC+ and then immediately lowers back down to around 30V or less. I suppose something in the primary PSU circuit was on its way out, letting AC ripple in, causing the interference. I'm not too sure where to start.
Tecmo New Astro City
-
- Posts: 28
- Joined: May 28th, 2012, 2:35 am
- Location: Tokyo, Japan
- eBay: 7raster
Re: Nanao MS9-29A Video Interference
Is this chassis being used in its original cabinet and frame? If you are using one you got elsewhere, check that it isn't missing the two blue X capacitors underneath the large power resistor in the primary power supply section. I have had similar patterns when those were not populated, albeit with an MS9-29T variant.