Logic Board - Macintosh SE Reloaded

[JDW]

Fred - did you notice the 65C22N in the space of the 53C80 SCSI controller?

Yikes! I overlooked that error when examining his photo, Kai. Could that have killed another chip on the board?

Unfortunately still stuck here!

Fred, can you please tell us exactly what you did prior to reporting that you are still stuck? (For example, I gave you a 7-point list in my previous post.)

Even so, my concern now is about what Kai pointed out. Using a 65C22N in the socket intended for a 53C80 is a potential problem.

 

[fred1212]

I put the correct chip in place of the wrong one and I too was concerned as to what else may have been damaged. I replaced the Ram with tested ram even though it was OK. Replaced the BBU as it was causing boot errors in test board. Checked board for solder bridges. So I now have a new 65c22 in the correct place the 53C80 SCSI in the correct socket. . I think something else is damaged as on first reboot I got vertical lines and then a partial unhappy mac image. But when I rebooted again back to the strange chequerboard. Put the ROM IWM BBU and RAM back in donor and all still work.

 

[JDW]

Well, it's going to take time to figure out which chips might be damaged due to the error of putting the 65C22N in the socket intended for a 53C80. You can see from my previous post that the correct SCSI chip has multiple Grounds, which means every pin marked GND gets constant Ground. Which means if the 65C22N ever did get powered, any HI output from the 65C22N on pins marked GND would have been a direct short and could have likely killed the 65C22N chip. That wouldn't be an issue since you have another 65C22N in the correct socket, but I suspect the 65C22N in the wrong socket is no longer usable.

But the question now is what about the other pins. We know from the drawings in my previous post that the 65C22N Ground is VSS pin-1. /DB7 is a signal on pin-1 of the SCSI chip. So if that signal wire acted as a chip Ground for the 65C22N, I wonder if /DB7 sourced more current than it was intended to source, and if so, which chip sourced that current. We also know pin-25 on the SCSI chip is constant Vcc 5V, and that was IRQB. Might have impacted the 65C22N, but it should have impacted anything else on the motherboard.

We also know that VDD (5V input) is pin 20 on the 65C22N, which is D5 on the SCSI chip socket. So the 65C22N chip was probably trying to draw its 5V power through D5 whenever 65C22N pin-1 received Ground.

• Mac SE Schematics: https://bit.ly/3I965Vq
• My BOM: https://bit.ly/3MF7BA9

 

[fred1212]

The 65c22n in the correct socket should be OK as it was a new one.

 

[fred1212]

I don't know if the SCSI chip is any good from the donor as most of the other chips have been no good, it must have been over voltaged at some time as the rom and iwm were cactus. The adb glue and bbu were from another board so hopefully they are good. I purchased as many new as possible to try and avoid this "learning curve". I think its probably for someone with better skills than me to tackle. Many thanks for your help with this. Definately a frustrating and expensive learning experience. Cheers

 

[JDW]

Well, please don't throw in the towel yet. I'm sure @Kai Robinson might have some more ideas up his sleeve.

 

[fred1212]

If anyone would like to have a go at fixing this please let me know. I've also posted this on Discord. Cheers

 

[eggimac]

Hello community
I got two SEs last year. One SE (5010) in working condition and the other SE 1/40 (M5011) with an exploded battery.

As you can see I've desoldered most of the critical components. The BBU has slightly corroded pins, which could be treated with white vinegar and the dremel to polish it.
Having the running machine helped me testing some components and I can confirm, the BBU, SWIM, both ROM work. So does the rest of the chassis of the M5011.
Hence the next step is ordering and soldering a spare PCB.

Since I have to order more then one board from PCB-Way, I'd rather ask around if someone else is interested in a new PCB. As I've seen there is a new version available on github (thank you Kai).
PM me, if interested - I'm in Switzerland and shipping in Europe is no problem.
Order will be placed around 20rh of March.
Cheers Peter

 

[Kai Robinson]

Hello community
I got two SEs last year. One SE (5010) in working condition and the other SE 1/40 (M5011) with an exploded battery.
View attachment 15541
View attachment 15542
View attachment 15543

As you can see I've desoldered most of the critical components. The BBU has slightly corroded pins, which could be treated with white vinegar and the dremel to polish it.
Having the running machine helped me testing some components and I can confirm, the BBU, SWIM, both ROM work. So does the rest of the chassis of the M5011.
Hence the next step is ordering and soldering a spare PCB.

Since I have to order more then one board from PCB-Way, I'd rather ask around if someone else is interested in a new PCB. As I've seen there is a new version available on github (thank you Kai).
PM me, if interested - I'm in Switzerland and shipping in Europe is no problem.
Order will be placed around 20rh of March.
Cheers Peter

Hi Peter, I'm sorry I have no boards left, I gave up stocking them a while ago and deferred to Maceffects in the US as that's where 90% of the interest was for them (as you know not many macs in Europe by comparison).

The latest version adds an extra pin header for an additional address line, to be able to potentially use the ROM from the Classic (it's been an idea...seeing as they're practically identical machines) just remember, order the SN75150 before TI stop making them!

Also, use silicon ark in the UK for the supply of the bournes filter networks, if you can.

 

[JdM74]

Greetings fellow SE Reloaded peeps.

I've been involved in one of these builds, about 9 hours into things with all going well....except for a couple of small parts that I still need to get [the kit I purchased with sockets, had the wrong size 28-pin connectors...too narrow]...but that part is all good.

However...with the thrills of victory, comes the agony of defeat. While removing chips from the old board [mainly ADB]...thinking I had removed enough solder to hot air station the rest out....disaster struck [picture attached]. Thankfully, there are some modern replacements to cover up this little error in judgement [lesson learned].

If there's anyone out there who might either have a spare 'genuine' ADB chip, one of the PIC16F88 replacements already programmed [I don't have a programmer, but might need to get one]....or one of Kai's adapters that's in a completed state that they're willing to sell...please PM me.

Many thanks!
Jason.

 

[Kai Robinson]

Well, that's one way to decap an IC!
My recommendation would be to build a new one from a PIC16F88 - not sure if there's anyone local to you that might have one - @max1zzz might have a DIP one floating around?

 

[callanbrown]

Just wanted to chime in with a problem I had with my Macintosh SE Reloaded board from MacEffects - an internal trace was missing/broken from one of the three RAM configuration jumper pins. So no matter what my configuration was, I would get a crash upon boot that looked a lot like the ones I've seen on the last few pages of this thread! I ran a jumper and it fixed everything.

I can't remember the details of which one was missing, but check the schematics and see if all three pins go to where they should.

EDIT: I'm thinking it was the center pin which should be grounded since that's the only internal one.

 

[JDW]

Just wanted to chime in with a problem I had with my Macintosh SE Reloaded board from MacEffects - an internal trace was missing/broken from one of the three RAM configuration jumper pins. So no matter what my configuration was, I would get a crash upon boot that looked a lot like the ones I've seen on the last few pages of this thread! I ran a jumper and it fixed everything.

Kai, is the MacEffects board a revision older than the matte black boards you kindly sent to me a long time ago?

The reason I ask is because I never had a problem with RAM configurations on my matte black boards.

As mentioned in the section of my video below, my matte black boards are revision 1.5 (not 1.5b) and I had to do one fix which I describe below:

My recommendation would be to build a new one from a PIC16F88 - not sure if there's anyone local to you that might have one - @max1zzz might have a DIP one floating around?

I mention that PIC16F88 replacement on page 4 of my SE Reloaded BOM.

 

[Kai Robinson]

There was a minor revision recently to add a breakout address pin to support the use of the larger ROM from the classic, but no - the MacEffects boards are a later revision than the original black and gold ones. I've checked the gerbers and they look fine from there so it must be a manufacturing error - @MacEffects have there been any complaints from recent purchases?

 

[MacEffects]

I've not heard of any complaints with the SE boards but then again they've not been selling with any level of frequncy recently. If you need a replacement, please feel free to PM me and I can get you taken care of.

 

[JDW]

I could have sworn I posted info about "Apple" logic board revisions and the associated ROM / IWM / SWIM chips somewhere in this forum, but none of my searches today found it. So I decided to post that info below in order to share it with @JdM74 and others.

Apple Macintosh SE LOGIC BOARD REVISIONS

1. OLD board: 820-0176-B (1986), 630-4125
• 342-0352-A, HI ROM
• 342-0353-A, LO ROM
• 344-0043-A or 344-0041-B, IWM (floppy drive controller)
• Only compatible with 800K drives, not 1.44MB
• RAM configuration set by resistors R35 & R36

2. NEW FDHD board: 820-0250-A (1988), 630-4250
• 342-0701, HI ROM
• 342-0702, LO ROM
• 344-0062, SWIM
• Compatible with 800K or 1.44MB drives
• RAM configuration set by jumper J16
• Kai Robinson's SE Reloaded board (sold by MacEffects) is based on this revision

NOTES:
• You can use the newer SWIM chip with the older ROMs, but you only get 800K drive compatibility.
• The old ROMs & IWM can be used in the newer revision motherboard. (SE Reloaded board)
• The newer ROMs & SWIM can be used in the older revision motherboard.
• The old ROMs & IWM chip are System 4.0 & Finder 5.4 (SSW2) compatible, but the newer ROMs & SWIM require System 6.0.3 minimum.

 

[rikerjoe]

Thanks for the recap, James. Out of curiosity I pulled a photo of my SE logic board to see what I have. I have the new FDHD logic board with the old ROMs and IWM. It’s my lone Mac with an 800k floppy drive. Thanks again!