Mac SE boots to black screen

[macsonny]

Hi All,

I have a Mac SE that both the motherboard and analog board have been recapped. The machine powers on and I get the familiar boing. Fans spin up but screen remains blank. Is this just likely a replacement of the two 470k ohm resistors R22 and R25?

Thanks

Sonny

 

[Juror22]

Are you sure that you have fully plugged in all the connectors? I know this is a basic step on re-assembly, but if you do enough of these, sometimes you notice the CRT board connectors might not be fully engaged after reassembly.

 

[macsonny]

Ok, some good news and some bad news. I checked all the joints and reflowed a few. Now get a nice boing boot sound but I get thin bright horizontal line across the scree which is a step up from the blank screen I guess.

I've tried reflowing the P1 connector and also replaced the TDA1170N IC (that's a fun job) but same result with the bright horizontal line.

Any other suggestions?

 

[ObeyDaleks]

Looks like you lost your vertical deflection. This could be an easy fix, or might require some troubleshooting of the analog board. The first thing I would check is the solder joints on the back of neck board, especially the ones that connect to the CRT pins. I would also check the neck board connector joints on the back of the analog board. All of those are prone to cracking and coming loose.

 

[macsonny]

Looks like you lost your vertical deflection. This could be an easy fix, or might require some troubleshooting of the analog board. The first thing I would check is the solder joints on the back of neck board, especially the ones that connect to the CRT pins. I would also check the neck board connector joints on the back of the analog board. All of those are prone to cracking and coming loose.

I'll give that a go tomorrow and report back.

 

[pezter22]

I just went through with the same issue on my MacSE FDHD recently. I recapped the analog board and replaced the same IC and the line remained. I ended up recapping the power supply I finally got a full regular screen.

A few weeks later I got a checkerboard screen which was a motherboard issue. I ended up buying a replacement board on eBay. So I am happy the SE is functional again.

 

[macsonny]

Did a reflow of suggested pins on analog board and also neck board. I have now noticed an odd re-boot sequence - wondering if the power supply is failing? See attached video.
View attachment IMG_2860.mov

 

[macsonny]

More progrès.. Changed out power supply and unit now starts up fine (no fluctuations) but sill horizontal white line. Any new suggestions?

 

[macsonny]

Bump

 

[pezter22]

I also replaced the video board on my troubled SE. Maybe that may help. It's not very costly to check.

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