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Baroni’s Collection

Posted by: elbaroni on 2019-05-09 14:30:41 Right. I’ve had a lot of these for a while, but I’ve only now caught my breath after having twins and moving house (in 2010...ahem) to start looking at them properly. First off is my Mac II upgraded to a IIfx. I don’t think this is very healthy.

Posted by: Byrd on 2019-05-09 16:19:26 Gack - I reckon around the RAM slots is where the pain repairing is, as they're so hard to clean and check I find.  Good luck with the repair!

Posted by: CC_333 on 2019-05-09 21:54:19 Yeah. That doesn't look to good.  At a minimum, those RAM slots should probably be replaced? c

Posted by: elbaroni on 2019-05-13 18:18:03 Moving on - my IIci. This one powers on and runs well, but won’t power off regardless of the rotation of the power switch and has no sound.  Odd artefacts on the screen when using built-in video on a portrait display at 16 colours. They seem to disappear when I change the desktop background, so perhaps just a CLUT issue.

Posted by: elbaroni on 2019-05-13 19:01:45 Artefacts. Bad RAM or CLUT? Thought it was linked to instability for a while, but then discovered my FloppyEmu was riddled with WDEF-A, which apparently has a bug on IIcis.

Posted by: Bolle on 2019-05-13 20:43:09 Needs new caps. There might be more damage in the power management circuit which prevents it from turning off correctly.

Posted by: elbaroni on 2019-05-14 05:28:23 Ah. Think you might be right...

Posted by: elbaroni on 2019-05-14 05:31:09 “Inspired” by my IIci and IIfx I also checked my IIcx:

Posted by: elbaroni on 2019-05-14 05:32:35 ...and IIsi:

Posted by: elbaroni on 2019-05-14 05:33:41 In short: bugger. Time to learn to solder. Seems to be the surface mount ones rather than axial, but guess I should get them all.

Posted by: elbaroni on 2019-05-14 06:29:21 Okay, so I find I need the following for the IIci (thanks to maccaps - the mm measurements are mine): [SIZE=12pt]8 - 47µf - 16V - SMT — 6.4mm wide[/SIZE] [SIZE=12pt]3 - 470µf - 16V - Axial — 21.5mm wide[/SIZE] [SIZE=12pt]2 - 10µf - 16V -SMT — 4mm wide[/SIZE] [SIZE=12pt]1 - 220µf - 16V - Axial — 16.3mm wide[/SIZE] [SIZE=12pt]I can’t find anything specifying the ESR I need though. Tantalum ones in the right (adjusted for down rating) voltage and capacitance range from 40 mOhms to 1.2 Ohms. [/SIZE] [SIZE=12pt]I see the caps Trag is offering Here are 800 mOhms ([/SIZE]This one), [SIZE=12pt]but I’d like to understand how to determine this. [/SIZE] [SIZE=12pt]As as may be obvious I know nothing about this stuff. Any advice gratefully received. [/SIZE]

Posted by: olePigeon on 2019-05-14 08:40:48 @elbaroni I used to be in the same boat as you not too long ago.  This is what I've come to understand about recapping and capacitors:  capacitance is what matters: the µf (microfarads) part.  So you want to make sure that one is equal to what you need.  The Voltage part is the rated tolerance.  This one can be equal to or greater than what you need.  So it's OK to put in a higher rated capacitor such as 47µf 20V in place of a 47µf 16V. ESR isn't specified because it probably doesn't matter too much in this case.  From what I've read, the lower the better. Next is to just make sure that it's the right type of cap.  Tantalums are good replacements for surface-mount caps.  Axials are for a couple of the horizontal through-hole caps, and radials for the regular through-holes. I just can't remember the type of capacitor, but there's one that LOOKS like an old electrolytic surface mount, but they're more reliable.  They're also more expensive, but they'll keep the old-school look of the motherboard without using tantalums.

Posted by: elbaroni on 2019-05-15 05:45:04 Thanks OlePigeon - that’s what I was guessing, but very reassuring to have someone confirm it.

Posted by: olePigeon on 2019-05-15 09:10:12 I think the ESR only really matters when you're dealing with heat-sensitive stuff.  According to the Googles, the lower the ESR, the lower the amount of energy is dissipated as heat.  So I would imagine that would make a difference if you're trying to make an efficient power supply and keep the heat levels down.  Or if a device operating in a temperature controlled environment.  That kind of stuff.

Posted by: elbaroni on 2019-05-15 17:39:39 This has been a good morning. A LaserWriter I, a LaserWriter IIf, a LaserWriter IIg, and a 13inch trinitron monitor.  The seller (near Bathurst in Australia, so not much use to most of you) has a massive array of apple stuff - at least four SE/30s with Ethernet cards, at least six complete Mac plusses, LC580s, apple IIes with monitors, PowerMac 6100, 5400ish, image writer IIs including one sheet feeder, several Inagewriter Is and a LaserWriter IIntx. All in a decrepit old house that’s being renovated. No power, so can’t test, but certainly worth checking out.  https://www.gumtree.com.au/s-ad/bathurst/computer-accessories/apple-vintage-computers-equipment/1217771713?utm_campaign=socialbuttons&utm_content=app_ios&utm_medium=social&utm_source=ios_social

Posted by: elbaroni on 2019-05-15 17:40:32 Oh, and open to offers for the lot. But it’s a lot. Prices reasonable without being a total steal.

Posted by: elbaroni on 2019-05-18 18:02:44 Finally got to trying the LaserWriter IIs. The IIg has the two red flashing lights which the service book tells me means new laser assembly. The IIf boots fine, shows up on a network, and prints...kinda...but with some paper feed issues.

Posted by: PB145B on 2019-05-19 05:12:09 but with some paper feed issues.  View attachment 27873 Paper feed looks fine to me!  :lol:

Posted by: elbaroni on 2019-05-20 03:57:00 And finally got to the Laserwriter I. Don’t know yet if it’s a plain I or a plus (or what version of the plus) but it looks super clean inside apart from one spider corpse. I’ve ordered a new toner cartridge because the foam on the old one has liquidated. Turned it on and it made all the right noises, identified correctly that there’s no paper (although there is a paper tray!), but I turned it off before the green light stopped flashing. Dunno about that serial port though. Still, found a db9 appletalk kit for $5 which is cool. It and the toner are en route.

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