Sega New Astro City- CRT PCB issue (brightness)

Pinball

Kula's Candy
Joined
May 7, 2012
Posts
294
Toshiba CRT brightness switches between bright and darker, apparently linked to the control PCB located in the control panel. Affected by vibration e.g. when I slam down panel (I think the small brightness pot on the PCB which had been pressed down onto PCB by frustrated previous owner presumably).

I checked for cold solder joints, and re-soldered brightness pot. Problem still present, I think due to faulty pot (you can see from one photo that it is cracked).

I can't find anywhere to get a replacement brightness pot or even the PCB. Does anyone know where to get these?? See photos.

Thanks guys!

IMG_8333.JPGIMG_8334.JPGIMG_8335.JPGIMG_8336.JPGIMG_8337.JPG
 
Last edited:

Kid Panda

The Chinese Kid
Joined
Jun 13, 2010
Posts
12,514
Have you jiggled the ribbon cable when it's plugged in? I had the same problem with one of mine a couple of years ago and it ended up beign the ribbon cable.
 

Pinball

Kula's Candy
Joined
May 7, 2012
Posts
294
I did and there is no obvious cause in the cables or components i.e. nothing happens. I should probably replace the cable/connector and control panel PCB, but cannot find anywhere that sells them. If anyone could provide a seller for these it would be awesome, as currently the cab is fcked.
 

Westcb

Give an Azn, A Break Here!,
Joined
May 17, 2012
Posts
1,190
I had this same issue, I switched out the pcb board and immediately fixed it. I want to say mine was isolated to the pot as if I put pressure on it I could trigger the problem. I also tried reflowing but it did not resolve the issue. If you can find a rating on the potentiometer you should be able to find a compatible replacement.
 

NoAffinity

Kuroko's Training Dummy
Joined
Mar 20, 2017
Posts
74
I've read that a good servicing of the faulty pot with deoxit can restore it.

Desolder pot. Clean with deoxit. Resolder pot.

I haven't personally tried this method, but it might be worth a shot if no other options are panning out.

Sent from my SM-G900V using Tapatalk
 

Pinball

Kula's Candy
Joined
May 7, 2012
Posts
294
I've read that a good servicing of the faulty pot with deoxit can restore it.

Desolder pot. Clean with deoxit. Resolder pot.

I haven't personally tried this method, but it might be worth a shot if no other options are panning out.

Sent from my SM-G900V using Tapatalk
I tried this today with some contact cleaner spray... and it worked! Sprayed the whole board and under components.

Brightness stays bright now, after several hours of solid play. I didn't even desolder first. I should have thought of this earlier- cheers :-)

Pretty impressive how long these 1994 devices have lasted, really.
 

Pinball

Kula's Candy
Joined
May 7, 2012
Posts
294
Nice! I love those simple fixes (aka inexpensive fixes). :)
Definitely! In addition, the connector was loose on the Toshiba monitor PCB- re-seating connectors always worth doing. It's still working perfectly now.

Next change is to upgrade speakers (awaited from Australia) :-)
 
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