Jump to content
PotatoFi

Macintosh SE FDHD No Video or Raster

Recommended Posts

Hey 68kmla! Newcomer here, I hope this type of post is appropriate. I've been looking for a good compact Macintosh community... this looks like it might be the one!

I've been wanting to own a compact Macintosh for a couple of years now, and I decided to tackle a restoration project 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? Anything I'm missing?

Edited by PotatoFi

Share this post


Link to post
Share on other sites

Hi there,

Welcome to the 68kmla. Thanks for liberating this poor fella. The FDHD is a great compact to start up with. You'll be able to create disks with your modern computer in no time. Before we go any further, did you dispose of the PRAM battery? If it's silver and red do it NOW before something really bad happens. If it's blue, purple or any other color get rid of it as it's not needed and it's probably dead anyway.

 

After that done...

Is the CRT glowing at the back? It might be very faint but if it's there, you have high voltage and that's good. 

I would reflow (or even replace, that tends to work better) every solder joint on the analog board. I know you already did J1 which is a common problem on those machines but I had the same issue with a Plus several months back and it turned out another joint was bad. So I would replace the solder on J1 and reflow/add a little more solder to the rest of the joints.

Also can you check the joints on the logic board connector for cracks? It's also pretty common for a joint to go bad there. And video gets to the analog board via this connector.

Last but not least, there might be a short on the CRT board. But only check this if you have high voltage. If you don't, there must be an issue with the Analog board.

 

Also, be careful around CRTs. Those things pack a lot of juice.

 

If you still can't get it working I'm sure someone here will come to your rescue with a spare analog board to do some testing.

Good luck!

Edited by BadGoldEagle

Share this post


Link to post
Share on other sites

If you have a scope then you will need to use it. If not, get one. 

 

Need to verify all your signals are coming from the logic board properly. the video signal, and both horizontal and vertical drive. 

 

Once you know thats good, you can trace that signal all the way through the analog board because the schematics are available. Then you willl find out right away where the video signal is dying off. 

Share this post


Link to post
Share on other sites

Any recommendation for the oscilloscope? I need one of those as well. Neil from RMC uses an app on his iPad and an adapter with prongs connected to the lightning port. It looks fancy but does it really work I wonder?

Share this post


Link to post
Share on other sites
24 minutes ago, BadGoldEagle said:

Neil from RMC uses an app on his iPad and an adapter with prongs connected to the lightning port. It looks fancy but does it really work I wonder?

Sounds like an Oscium oscilloscope. I've worked with them directly. Very good guys. They've worked black magic to get that gear working on the stringent power that a lightning port provides. Wish I had one! 

Share this post


Link to post
Share on other sites

I dont know if it can handle high voltages or the bandwidth needed to handle what your testing. Most of those systems only work in the audio spectrum, but again, it depends on the design of the setup. 

Share this post


Link to post
Share on other sites
On 12/2/2018 at 2:39 AM, BadGoldEagle said:

Welcome to the 68kmla. Thanks for liberating this poor fella. The FDHD is a great compact to start up with. You'll be able to create disks with your modern computer in no time. Before we go any further, did you dispose of the PRAM battery?

Thank you! And yes, I selected the FDHD specifically for the 1.44 mb floppy drive. Seemed like a great low-cost alternative to the SE/30.

 

As for the PRAM battery, absolutely. I tossed it first thing, and replaced it with a "leakproof" battery from RetroFixes. If I ever plan to store it long-term I will remove the battery.

Quote

Is the CRT glowing at the back? It might be very faint but if it's there, you have high voltage and that's good.

Yes, there's a tiny orange glow. Like a butane soldering iron. Does this indicate that the flyback transformer is operational? My knowledge of CRT's is very limited, it seems like a lost art...

Quote

Also can you check the joints on the logic board connector for cracks? It's also pretty common for a joint to go bad there. And video gets to the analog board via this connector.

The joints on that connector look absolutely beautiful. I did use my multimeter to check for continuity from the logic board to the analog board and they all checked out. Do you still recommend a reflow?

On 12/2/2018 at 2:39 AM, BadGoldEagle said:

I would reflow (or even replace, that tends to work better) every solder joint on the analog board.

The solder joints on the analog board look super nice. Should I still do this? I should probably invest in a solder sucker.

On 12/2/2018 at 2:39 AM, BadGoldEagle said:

If you still can't get it working I'm sure someone here will come to your rescue with a spare analog board to do some testing.

I can also buy a known-good analog board on eBay for about $40 including shipping. Would that be a smart move, or should I hold off?

On 12/2/2018 at 7:37 AM, techknight said:

Need to verify all your signals are coming from the logic board properly. the video signal, and both horizontal and vertical drive. 

 

Once you know thats good, you can trace that signal all the way through the analog board because the schematics are available. Then you willl find out right away where the video signal is dying off. 

I have a friend with a scope, and know-how to use it. Will give this a go soon.

 

Thank you both VERY much for your help.

Share this post


Link to post
Share on other sites

I would still reflow those joints. Mine looked perfect but they weren’t. 

 

You’ll need a solder sucker sooner or later. The PSUs in those Macs are getting weaker by the day. You’ll probably have to recap it sometime in the near future. So a solder sucker is definitely a good investment.

 

I’m no CRT expert myself but you most certainly have high voltage, so the flyback should be good. If reflowing everything on the board doesn’t fix it, you’ll have to go signal hunting. 

 

I don’t think the logic bord’s bad (but I’m no expert unlike techknight). Thankfully the SEs don’t have a complex video circuit (compared to its bigger brother the SE/30). IIRC it’s incorporated in the GLU logic chip and this one doesn’t go bad very often. But the joints on the LB connector can be bad. So I would reflow them too.

 

Again that’s what I would do. It may not help at all. Techknight’s method is definitely the best. 

Share this post


Link to post
Share on other sites

Great news! The Macintosh SE is happily humming next to me on my desk with a working CRT. The culprit was a disconnected leg on a component, specifically this filter at F1. The damage was obscured by a glob of hot glue.

 

IMG_0526.thumb.JPG.4b1fdedff686034487dc2df98f770956.JPG

 

And here it is after it's first working boot in who knows how long:

 

MacintoshSE.thumb.JPG.36ed8e689418c13061cfa3b7e5d93fb9.JPG

 

I hugely appreciate your help with this. I managed to write some floppies for it with dd on my MacBook Pro + USB floppy drive last night and reinstall System 6.0.8. It felt great to play Sim City on it for a few minutes. I'm impressed that everything works, including the floppy and hard drives. Future plans for this machine:

  • Retrobrite the front (I've already done the back)
  • Install 4 MB of RAM
  • Install the PRAM battery (I forgot to install it in my haste to put it together)
  • Perhaps take apart and lubricate the floppy drive

Share this post


Link to post
Share on other sites

Bah, look what I've done. I didn't want to start another thread for this one because it's so dumb. I was pulling things back apart to retrobrite the front, lubricate the floppy drive, and install the PRAM battery when I did this:

 

IMG_20181210_211657.thumb.jpg.c491aa1eee81ffe4696fa88c5c6e5113.jpg

 

Now I know to reach in there with some pliers and pinch the clip instead of just trying to pull it off. The picture barely shows it, but there is a small wire protruding from the hole. Am I okay to just screw that screw back in there, and allow it to make contact with the wire? Ever had this happen?

Share this post


Link to post
Share on other sites

Congratulations for fixing it ... and breaking it short afterwards :-x Don't worry, we've all done it.

 

But I've never seen that happen before though. 

If nothing fell inside the tube, you should be able to just reassemble the two pieces and put it back together.

Were you trying to remove the front panel? If you were, here's a tip for you in the future: You can pick up the analog board and the CRT as one piece (so you won't have to remove that anode cap again). Just loosen the A/B and you should be able to remove the two CRT screws hidden just under the board. Then lift up the whole thing and set it aside. 

 

Oh and if you really plan on using the most of your FDHD, you should consider an SCSI2SD and/or a Floppy EMU. The hard drives are on their last legs and SSDs are much faster!

Share this post


Link to post
Share on other sites

Nothing fell inside the tube, as soon as I realized what happened I became extremely paranoid about keeping that from happening! There's exposed wire in there... I think I'll wrap it around the screw and put it back together very carefully. I'll get as good of contact as I can.

 

As for the hard drive, I have a friend with a SCSI2SD 5.1 who has offered it to me as a gift. I will absolutely be replacing the hard drive with it. I'll probably do a 4MB RAM upgrade at the same time.

 

I just checked my retrobrite progress on the front panel... it's looking absolutely beautiful. I'm going to leave it under the light for a couple more hours and call it done. Then I just need to lubricate the floppy and reassemble, and this thing is ready for Oregon Trail, Lemmings, and Sim City!

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×