SE/30 EPROM

[billynomates]

Hi all, just bought a(nother) SE/30 on ebay, so I can practise with my imminent capacitor replacement for my 'proper' SE/30 running A/UX. The monitor's a bit ghosty and there's no sound, so presumably it's suffering from the usual problem. xx(

I've taken the logic board out, and it's an old one - it's got a socketed 030 chip, which is a nice bonus.

It also has an EPROM based video ROM chip - with an Apple sticker over the U/V window - with © 1988 and another number on it (presumably a part number) - I can get you this later if anyone's interested...

All the other boards I've seen have socketed ROMs here, not EPROMs.

Just thought I'd mention it... Wonder why Apple have put an EPROM here instead of a 'normal' ROM... :?:

 

[LCGuy]

Perhaps its a very early production model, and there was a part shortage at the time this machine was built? Or perhaps it could be a *very* late prototype? Does the board differ to a regular production SE/30 mobo in any other ways?

 

[billynomates]

There is a (blue) wire soldered between the aluminium 'can' (looks like an oscillator - located by the power plug on the board) and the small square chip next to it.

The capacitors seem to be pretty messed up - there's no startup chime / sound at all (whereas my other SE/30 is feint but not completely gone), and there's a bit of gunk on the board where they've leaked. The thing works pretty well though - no simasi on start, although I haven't tried with any extra memory or a bigger disk.

Apart from that, it's in pretty good condition. The CRT is a clinton model, the case is all okay, although it has had a second monitor board in there at some point as the original PDS blanking plate has gone and a radius equivalent is there.

 

[billynomates]

Sorry, it's a green wire. Although I'm pretty sure that doesn't matter

 

[Bunsen]

Is it the green wire, or the blue wire? Onoes, don't cut the red wire, or it'll axplodez!!!

 

[JDW]

Some crystal clear closeup photos of this EPROM would be nice (preferrably by a camera mounted on a tripod, set to the lowest possible ISO setting).

 

[billynomates]

 

[JDW]

Thank you for the photo.

There are a number of differences between the older and newer boards, so one need not be worried about the green wire soldered to the Xtal. Such wires just show that the engineers made a little goof, which they then fixed at a later time in a new circuit board revision. So long as you don't desolder such wires, you will be okay.

I also found it interesting that Apple used a different kind of fuse in F1, F2 and F3. Those circular blue parts almost look like a modern day MOV. Later boards have a silver SMD fuse.

Nothing too remarkable about the video ROM either. Early edition circuit boards can often be considered "a work in progress" so windowed EPROMs are not something that would get me excited. If anything, they require a little more care. Don't remove that sticker and the leave that EPROM in the sun for extended periods of time. UV light will wipe it clean!

Many sing praises over these early boards due to the socketed CPU. I myself no longer get excited about this point because, after having been an active member of EBAY for many years now, I've never ever seen any SE/30 CPU socket upgrades pop-up for sale. So unless that miraculously changes, you basically have a "feature" that you can make no use of (which makes it no more of a "feature" than my soldered-in CPU). Sorry to be so pessimistic about this point. But in all honesty, there is more hope of securing a rather expensive grayscale video setup for the SE/30 than a socketed CPU upgrade at any price. You cannot buy what's never available for sale.

Here are photos so everyone can compare (noting that mine is rotated 180° from the other photo):







Now get to work on re-capping that board and enjoy your SE/30!

 

[billynomates]

Cool! Thanks for all the info... Very interesting...

I'll get the soldering iron out, and try not to ruin anything!

 

[billynomates]

Ooops! Missed one other thing - looks like C12 is in a different location (the other side of the ROM slot)

Cheers again!