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Another MS8-29FSG I am working on

cruzlink2

cruzlink2

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This one gave up the ghost on one of our Astros not too long ago. It went from working to showing a black garbled image in the middle. I reflowed all suspect joints fully recapped it and replaced all transistor in the B+ area except for the 2SC4157. It turns on fine now but shows what you see in the pictures. Any suggestions will be greatly appreciated.
 

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Get another chassis or check the regulator chip and seach voltage decrease in B+
 
Mine looked like that. I sent it to PNL for repair and they did fix it but wouldn't tell me how. Also it stopped working after a few hours. I sent it to arcadecup but it's still gonna be a while before I get it back.

I hate the ms8.
 
It Is the vertical PCB mounted in front of the HOT, consider this pcb as an IC and it is responsible of any sort of sync issue... Most likely a cold solder joint or in worst case an smd resistor or smd diode wich is mounted on that pcb just failed. .. Those are not easy to fix but you can swap from a donor chassis.
 
Mukuro_W said:
It Is the vertical PCB mounted in front of the HOT, consider this pcb as an IC and it is responsible of any sort of sync issue... Most likely a cold solder joint or in worst case an smd resistor or smd diode wich is mounted on that pcb just failed. .. Those are not easy to fix but you can swap from a donor chassis.
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Which one of these boards are you referring to.
 

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The one on the Last photo is the sync ic.
 

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Only one thing tested weird and it was the transistor with the K on it. I have no idea what the part number is though.
 

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Fixing those PCB is not an easy task , if you have a donor chassis wich have a faulty flyback you can swap this pcb and fix this chassis.
 
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I found out what the part number was on the K labeled transistor and it's actually a type of diode, with the schematics I was able to test it properly and it tested good.
 

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notsonic said:
Mine looked like that. I sent it to PNL for repair and they did fix it but wouldn't tell me how. Also it stopped working after a few hours. I sent it to arcadecup but it's still gonna be a while before I get it back.

I hate the ms8.
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ever got the chassis back from arcadecup?
 
I did get it back and it mostly worked. Sometimes it would still go into HV shutdown on a cold start. I was also having a lot of convergence issues, not necessarily related to the chassis. I found someone in Staten Island that does arcade repairs and was willing to adjust the convergence and take a look at the cold start issue. I dropped it off, tube and all. He's backed up so it'll probably be a while before I get it back.
 
notsonic said:
I did get it back and it mostly worked. Sometimes it would still go into HV shutdown on a cold start. I was also having a lot of convergence issues, not necessarily related to the chassis. I found someone in Staten Island that does arcade repairs and was willing to adjust the convergence and take a look at the cold start issue. I dropped it off, tube and all. He's backed up so it'll probably be a while before I get it back.
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Staten Island, damn that's close to where I am at in Brooklyn.
 
Mukuro_W said:
Anyway that part should be : 2SC3052-E sot23

A scope shoud help....
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Finally got around replacing the transistors on the sync board, will test when I have time.
 

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notsonic said:
I did get it back and it mostly worked. Sometimes it would still go into HV shutdown on a cold start. I was also having a lot of convergence issues, not necessarily related to the chassis. I found someone in Staten Island that does arcade repairs and was willing to adjust the convergence and take a look at the cold start issue. I dropped it off, tube and all. He's backed up so it'll probably be a while before I get it back.
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Ever got the chassis back from the staten island guy?
 
Oh yeah, it still has the same HV shutdown problems. Every repair guy has ghosted me when I get it back. I gave up on it.
 
notsonic said:
Oh yeah, it still has the same HV shutdown problems. Every repair guy has ghosted me when I get it back. I gave up on it.
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did the sync issue go away? can the hv issue be an issue with the flyback? did the flyback ever get replaced?
 
cruzlink2 said:
did the sync issue go away? can the hv issue be an issue with the flyback? did the flyback ever get replaced?
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I think it syncs fine, and the picture is good when it's good. The flyback is still original. I guess I could try to replace it, that's easier than swapping a yoke. Are they available?
 
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