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#1 2018-12-01 23:49:45

PotatoFi
Member
From: Boise, ID
Registered: 2018-12-01
Posts: 3

Macintosh SE No Video or Raster

I've been wanting to own a compact Macintosh for a couple of years now, and I decided to try to save some money by buying a project machine. I ended up getting a Macintosh SE FDHD in nice physical condition, but while it chimes and sounds like it's booting, the display is completely dark.

Here's what I've tried so far:

  • Checked brightness knob

  • Checked CRT neck board for proper seating (did not fully remove and reseat)

  • Reflow and check J1 connector on the analog board

  • Test resistor at R22 (Per Dead Mac Scrolls, page 150)

  • Measured voltages at the floppy connector, and found 12.00v, 5.00v, and -11.84v

  • Checked all analog to logic wires for continuity (Per Dead Mac Scrolls, page 26)

  • Checked for CRT glow at the neck, and there is a tiny orange glow (but I'm not exactly sure what to look for)

  • Replaced PRAM battery (unrelated, just maintenance)

  • Blew all of the dust out (unrelated, just maintenance)

  • Did retrobrite on the case and it came out beautifully, looking forward to retrobiting the front but I'm waiting until the machine works

At this point, I'm at a complete loss as to what to try next. I'd really like to revive this machine. Any ideas?

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#2 2018-12-02 08:40:14

French
Member
Registered: 2017-06-17
Posts: 20

Re: Macintosh SE No Video or Raster

Analog board issue (capacitor or Flyback transformer), CRT issue (cracked neck) or connector from the analog board (re flowing is not working all the time, i remove the old  solder and put fresh one afterwards)

hitting the side should bring some picture if this is the issue.

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#3 2018-12-02 17:06:44

mcdermd
Member
From: Corvallis, OR
Registered: 2014-05-12
Posts: 1,002
Website

Re: Macintosh SE No Video or Raster

It's not a cracked neck - you know when that happens

This is what a cracked tube looks like


Daily Drivers: 27" iMac 2.8 GHz Quad-Core i7 (Late 2009), 21.5" iMac 2.7GHz Quad-Core i5 (Late 2013), 11" Macbook Air 1.6 GHz i5 (Mid-2011)
See the restored heroes here.

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#4 2018-12-03 05:22:56

PotatoFi
Member
From: Boise, ID
Registered: 2018-12-01
Posts: 3

Re: Macintosh SE No Video or Raster

Thanks for the suggestions!

I'm happy to report that it is definitely not that. There is a tiny orange glow in the neck (about like the glow of a butane soldering iron) when the Macintosh is powered on.

French wrote:

Analog board issue (capacitor or Flyback transformer)

Is there a reliable way to test these? I have a simple Craftsman multimeter and very little knowledge about high voltage circuits (basically, stay away from them when they're on).

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#5 2018-12-05 19:55:18

mcdermd
Member
From: Corvallis, OR
Registered: 2014-05-12
Posts: 1,002
Website

Re: Macintosh SE No Video or Raster

PotatoFi wrote:

There is a tiny orange glow in the neck (about like the glow of a butane soldering iron) when the Macintosh is powered on.

That's the heater voltage and it's a good thing.

PotatoFi wrote:

Is there a reliable way to test these?

You need a High Voltage probe for your meter to test HV at the anode (the big red wire with the suction cup). You should be able to lookup where to test for B+ voltage and determine if the monitor is in HV shutdown.

I've seen several that had bad 4-pin connectors from the analog board to the CRT yoke. Check to be sure the solder is not cold and the connector is not burnt.


Daily Drivers: 27" iMac 2.8 GHz Quad-Core i7 (Late 2009), 21.5" iMac 2.7GHz Quad-Core i5 (Late 2013), 11" Macbook Air 1.6 GHz i5 (Mid-2011)
See the restored heroes here.

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#6 2018-12-10 03:59:30

PotatoFi
Member
From: Boise, ID
Registered: 2018-12-01
Posts: 3

Re: Macintosh SE No Video or Raster

I have some excellent news:

IMG-0530.jpg

The filter at L1 on the analog board had a disconnected leg. I noticed it while pulling off capacitors to test them with an ESR meter that I borrowed. Just as I was thinking "why did they glob glue everywhere here" I poked at the filter and noticed how loose it was. Fixing it was very quick work with the soldering iron!

Now, I just need to figure out why my ADB Apple Keyboard II keeps the machine from booting all the way when plugged in...

I am super, super excited that it is working again! Absolutely thrilled! I can't wait to finish the restoration.

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