Macintosh SE FDHD problem :P

[MacintoshProblems:P]

Hello,
so I recently found some old macintosh computers lying around so I wanted to see if I could make any of them boot and work. After a lot of tinkering (and re-capping it twice), I decided that I really don't know what's causing the issue and I can't find anyone that has/had the same issue as me! It boots fine, system is great and doesn't seem to have any issues. The fan spins up and I can hear the Beep although before booting there's this pattern of lines which I can't quite figure out what is causing the issue.
I'll put some images so you guys can see what is happening, if you see that there are lines on the crt it's because of the matching frame rate of the camera and the screen.
Cheers!

 

[MacintoshProblems:P]

here are some more images of what happens next

 

[Nixontheknight]

when you recapped the machine, did you just recap the logic board or did you recap the analog board as well? I'd recommend trying different RAM to see if anything changes

 

[MacintoshProblems:P]

when you recapped the machine, did you just recap the logic board or did you recap the analog board as well? I'd recommend trying different RAM to see if anything changes

Yes I did, I also re-capped any that had the same voltage just to be sure. It had an error before re-capping. I re-capped all the 33uF 16v on the logic and all of the electrolytics on the analog board. I didn't touch any of the power supply ones because it gives the correct voltage and it works fine. I just changed the ram to two ram sticks I had lying around but it gave me another type of error with a crystal crash on the monitor, kind of to be expected since the se is very picky.

 

[Nixontheknight]

Yes I did, I also re-capped any that had the same voltage just to be sure. It had an error before re-capping. I re-capped all the 33uF 16v on the logic and all of the electrolytics on the analog board. I didn't touch any of the power supply ones because it gives the correct voltage and it works fine. I just changed the ram to two ram sticks I had lying around but it gave me another type of error with a crystal crash on the monitor, kind of to be expected since the se is very picky.

I'd recommend recapping the power supply. It may be giving the right voltages, but the ripple may be too much for the logic board

 

[MacintoshProblems:P]

even though after that it boots and works fine? I already checked the power supply and it all seemed fine
Edit. My fluke multimeter reads 12.54v and 5.18v so idk it seems fine I guess

 

[MacintoshProblems:P]

Update: the psu is fine after re-capping and... nothing changed.
The good news is that it has better reading now: 12.11v instead of 12.54v and 5v instead of 5.18. The bad news is that nothing changed: the screen is still the same.

 

[MacintoshProblems:P]

Update 2:
First, I changed all 3 ROM: High, low and the Woz one (swim).
Nothing changed.
Second, I changed 2 simms doing an upgrade to 2.5Mb cutting one leg of the resistor r35,
Nothing has changed once again.
Third I found a corroded capacitor (this SE went to hell and back), the name's c20 (from the image).
In it's origin this cap (104z) is a Unitrode Ceramic Capacitor, like the attached image, so it's an SMD incapsuled in glass with 2 legs to insert it in through-hole circuits. Not having any available original ones, I installed a polyester one as a momentary replacement.
Nothing changed for the third time.
On the board there are more than 30 units of these caps, some with corroded legs, others having a dark inside and others clear like they got hit from humidity (considering they all have the same capacity). Might this be the problem?
I would need a hand from you guys!!!
In the mean time I put it back together as it was, excluding the ceramic cap that I was searching.
I'm going to attach some photos, Cheers!

 

[mg.man]

Nothing changed for the third time.

I'm a little lost... what is the actual issue? I see a Happy Mac toward the top, then an About the FInder. It appears to be booting?

 

[joshc]

I'm a little lost... what is the actual issue? I see a Happy Mac toward the top, then an About the FInder. It appears to be booting?

The fan spins up and I can hear the Beep although before booting there's this pattern of lines which I can't quite figure out what is causing the issue.

In the first post OP mentioned that it always displays the pattern of lines before a successful boot.

I would've thought ROM related but the ROMs have been swapped.

 

[mg.man]

I would've thought ROM related

Yeah, sounds like - if that indeed is 'the issue'. It could be thermal-related or even RTC? But it's not like a un-initialised RAM pattern, since there doesn't appear to be any repeating / symmetry to that image. @MacintoshProblems:P - is the pattern identical every time? Also, what happens if you let the SE run for a while (and get nice and warm), shut it down + turn it off, then immediately turn it back on? Lines again?

 

[MacintoshProblems:P]

In the first post OP mentioned that it always displays the pattern of lines before a successful boot.

I would've thought ROM related but the ROMs have been swapped.

Exactly! This is the weird problem that I'm facing! The macintosh after the boot works perfectly but before the boot sequence there's this weird error.

Yeah, sounds like - if that indeed is 'the issue'. It could be thermal-related or even RTC? But it's not like a un-initialised RAM pattern, since there doesn't appear to be any repeating / symmetry to that image. @MacintoshProblems:P - is the pattern identical every time? Also, what happens if you let the SE run for a while (and get nice and warm), shut it down + turn it off, then immediately turn it back on? Lines again?

Yes, the pattern is the same every time even after some time and at different temperatures.
I immagined that it could be a problem related to reading times of the Rom... In fact after 10 seconds where the "Barcode" appears, the mac does a regular boot sequence. If I re-start it it works fine, if I turn it off and on again the lines appear again.

 

[mg.man]

Yes, the pattern is the same every time even after some time and at different temperatures.

That is strange. Almost like a capacitor needing to 'charge up'? What happens when you "Restart"? Also, when you hit the programmer (Reset?) switch -- i.e., try a 'warm' boot? Same lines?

 

[Phipli]

It does feel like an incorrect capacitor has been fitted and a voltage is taking a while to stabilise. You mentioned recapping twice, does that include the PSU and analogue board? Can you verify the components against an alternative list? I have a list for the PSU somewhere...

 

[Phipli]

Recapping a Mac SE power supply and analog board

I am having some trouble coming up with the right caps. What do I need and how much do you think it will cost. Thanks

68kmla.org

You'll want to check the analogue board too if you did that.

 

[cheesestraws]

Agreed, looks like a delayed initial reset to me. Peer suspiciously at the PSU and supply voltages for starters

 

[MacintoshProblems:P]

That is strange. Almost like a capacitor needing to 'charge up'? What happens when you "Restart"? Also, when you hit the programmer (Reset?) switch -- i.e., try a 'warm' boot? Same lines?

I have to try with the reset switch, with a restart it always gives the same lines.
In photo that I attached to this post, there are the Rom that I used for resolving the issue, but it didn't work. I won't hide that I tried to interchange only the Woz chip but I had a sad mac.

It does feel like an incorrect capacitor has been fitted and a voltage is taking a while to stabilise. You mentioned recapping twice, does that include the PSU and analogue board? Can you verify the components against an alternative list? I have a list for the PSU somewhere...

I already thought of the psu but I don't think that I made any mistakes while changing the caps: I checked multiple times before giving current. I thought about doing a ripple check with my oscilloscope to see if there was any voltage spikes. It's interesting from what you're saying verifying that the voltages exiting from the psu are present at the same time when turned on.

Recapping a Mac SE power supply and analog board

I am having some trouble coming up with the right caps. What do I need and how much do you think it will cost. Thanks

68kmla.org

You'll want to check the analogue board too if you did that.

I also changed all of the caps on the analog board and on the logic board.
For the value of the caps I reffered to the original schematic and the caps present on the boards. There weren't any discrepancies.

 

[cheesestraws]

You want to check how long the voltages take to stabilise. A scope probably is your best friend here if you have one.

 

[Phipli]

For the value of the caps I reffered to the original schematic and the caps present on the boards. There weren't any discrepancies.

There are a number of parameters though, personally I find it extremely difficult to get the "right" capacitors. The largest capacitor in the PSU for example, is near impossible to get at the same specification and connectors.

Did you pick appropriately low ESR capacitors for the output stage of the PSU?

 

[MacintoshProblems:P]

There are a number of parameters though, personally I find it extremely difficult to get the "right" capacitors. The largest capacitor in the PSU for example, is near impossible to get at the same specification and connectors.

Did you pick appropriately low ESR capacitors for the output stage of the PSU?

Unfortunatley I don't have an ESR, that would be the next thing to buy. At the moment I'm trying to find either nippon Chemi-con or Rubycon if I'm lucky. Every now and then I happen to find caps with dubious origins such as Jamicon, Daewoo and other chineese crap (I say chineese because I think that most they misbehave). My old styroscope is an analog one with a CRT so I know that it's not much but it works