Mac SE FDHD lines on screen no boot chime

[pezter22]

I have a problematic Mac SE FDHD with lines going across the screen. I recently recapped the analog board and the (Sony) power supply. I also tried a second analog board and a (Apple/Hitachi) power supply and had the same screens. I am getting proper voltages on the power supplies and I have 11.9v and 4.9v at the floppy connector.

There is a similar post here from 2021 with what appears to be a very same issue, but unsure because I have tried two different analog boards. The board is clean and the Mac was booting correctly right after the analog board and power supply recap.

A few days ago, I went to boot it after a month and got the no chime and lines. I went through the solder joints on the analog boards again. Would this be a ROM issue? Or another IC that would cause this?

Any help would be appreciated.

Other Mac SE with similar issue in the forum.

Mac SE FEHD - first checkerboard, now stripes, looking for repair guidance

Hi all! First post here, hoping for some advanced help. Thanks in advance! I picked up a Mac SE that I'm trying to get working again. It was initially booting to a checkerboard screen: My first stop was to clean the motherboard (which didn't look too bad) with alcohol, and re-seat the ROMs...

68kmla.org

 

[Nixontheknight]

I have a problematic Mac SE FDHD with lines going across the screen. I recently recapped the analog board and the (Sony) power supply. I also tried a second analog board and a (Apple/Hitachi) power supply and had the same screens. I am getting proper voltages on the power supplies and I have 11.9v and 4.9v at the floppy connector.

There is a similar post here from 2021 with what appears to be a very same issue, but unsure because I have tried two different analog boards. The board is clean and the Mac was booting correctly right after the analog board and power supply recap.

A few days ago, I went to boot it after a month and got the no chime and lines. I went through the solder joints on the analog boards again. Would this be a ROM issue? Or another IC that would cause this?

Any help would be appreciated.

Other Mac SE with similar issue in the forum.

Mac SE FEHD - first checkerboard, now stripes, looking for repair guidance

Hi all! First post here, hoping for some advanced help. Thanks in advance! I picked up a Mac SE that I'm trying to get working again. It was initially booting to a checkerboard screen: My first stop was to clean the motherboard (which didn't look too bad) with alcohol, and re-seat the ROMs...

68kmla.org

reseat ROM and RAM, if it persists, try replacing the ram with a new set of 4

 

[Berenod]

reseat ROM and RAM, if it persists, try replacing the ram with a new set of 4

Yup, just be very gentle with the plastic retaining pieces, they snap easily.
Some Deoxit would also be a good strategy!

 

[pezter22]

I had to wait until today when I received a different set of 30 pin RAM chips. These are 30 pin 9 chip Parity 70ns FMP SIMMs stated to work with MacSE and Plus.

I removed and cleaned the two ROM chips and the and used Deoxit on the sockets and the RAM sockets.

I bought four 1mb RAM chips (My other ones are also four 1mb). I even placed a jumper on the 2/4 RAM pins.

Sadly I got a similar result. No chime, but a different pattern.

This is a very clean board.

What chip would prevent a boot with no chime and a patterned screen? ROM? RAM? another IC?

First image is my ROM on the clean board.
Second image is screen image is with new RAM.
Third image is with old RAM and jumper in place (similar to earlier post)
I did not take an image of the screen with no RAM jumper and old RAM. It was similar with the multiple horizontal lines going across the screen that I had earlier.

Any help and guidance would be appreciated.

Thank you.

 

[Phipli]

I even placed a jumper on the 2/4 RAM pins.

You want no jumper at all for 4MB. The silk screen doesn't make sense. The manual even tells you to ignore it.

 

[pezter22]

You want no jumper at all for 4MB. The silk screen doesn't make sense. The manual even tells you to ignore it.

I'm aware. I just wanted to see the result on the screen. When I did take this apart originally, the two left pins were touching. Pin one was bent over onto pin two - similar to a jumper being installed. Maybe a previous owner had bent the pin to touch. This isn't a Mac I have previously used and it had booted before a analog and power supply recap.

I don't believe it's a RAM issue. I have another MacSE (800k), so tomorrow I am going to swap things around. First with the motherboard to check if it boots or remains the same. At least then I can see if it's a motherboard issue or analog board.

 

[pezter22]

Okay, Weird one.
I have another MacSE 800k and decided to try the MacSE FDHD motherboard in the 800k case. It booted without issue. I placed the 800k motherboard in the FDHD case to check if maybe it was the analog board issue. It booted too.

Unsure what caused the issue, but if place the motherboards back in their correct cases, the FDHD produces no chime and boots to a pattern screen.

I think I may just swap the motherboards and leave it at that.

Weird. This has me stumped.

 

[pezter22]

Well that didn't last long. I swapped the motherboards and the FDHD board went back to no chime and lines on the screen.

I am going to reflow some of the solder joints on the board. It must be a connection issue.

 

[pezter22]

I went through all the solder joints on the back of the board with my soldering iron and got the same result. horizontal lines.

I also tried using some 30 pin 9 chip parity 70ns FMP SIMMs I bought on eBay that are supposed to be for the MacSE.

I got a checkered screen pattern and no boot chime.

ROM chips?

 

[pezter22]

Repaired with a replacement motherboard. I purchased a eBay MacSE 800k motherboard. After a test boot, I placed the FDHD ROM and SWIM IC's on to the replacement board and it booted. This means the ROM/SWIM chips are good and that there is a broken trace on the board, possibly between the BBU and ROM or RAM.

The machine works fine now. I'll look into the old board some time later this summer.

 

[stansteph54]

any recent update? thanks

 

[pezter22]

any recent update? thanks

I ended up buying a replacement motherboard. I bought a 800k motherboard and installed the ROM from the FDHD board. So at least it is reading the 1.4mb floppies.

I am guessing there is a broken trace near the RAM, CPU and BBU chips.

I was looking at one of these MacSE reloaded boards to play around with. It's just $50.

Macintosh SE Reloaded Logic Board

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