August 2021 - vcf-midatlantic

Re: [vcf-midatlantic] Apple Branded Mid-80's Memory Compatibility Question.
by Ian Primus 09 Aug '21

09 Aug '21

The later ROM revisions actually do have a reasonably competent memory test you can access with control open-Apple solid-Apple reset, but the first rev, ROM 255, doesn't. Also, if you haven't seen it yet, the ROM4x project adds some neat stuff as well: https://github.com/mgcaret/rom4x If I'm working on a IIc and I'm at home and have access to my equipment, I usually wind up burning a new ROM and upgrading it, and then use that to find the bad RAM. Note that if you're going from a 255, the new ROM is bigger, so you'll have to change a couple motherboard jumpers. It's a good idea to upgrade off of 255 if that's what your machine has (Do a PRINT PEEK(64447) and see what version you have, would be 255, 0, 3, or 4), since the later revs add Unidisk 3 1/2" support and fix some serial bugs that let it work reliably at higher speeds. -Ian On Mon, Aug 9, 2021 at 8:18 AM Mike Willegal via vcf-midatlantic <vcf-midatlantic(a)lists.vcfed.org> wrote: > > Ian, > > Thanks for confirming. It sure doesn’t look like there is clearance for a socket. I’ve also fixed a couple of Mac128ks with bad memory over the years, but those systems did a POST that made debugging significantly easier. This failure was in auxiliary memory and I ended up modifying my 6502 memtest program to run from auxiliary memory in order to identify the bad chip. > > Mike Willegal

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Re: Apple Branded Mid-80's Memory Compatibility Question.
by Mike Willegal 09 Aug '21

09 Aug '21

Ian, Thanks for confirming. It sure doesn’t look like there is clearance for a socket. I’ve also fixed a couple of Mac128ks with bad memory over the years, but those systems did a POST that made debugging significantly easier. This failure was in auxiliary memory and I ended up modifying my 6502 memtest program to run from auxiliary memory in order to identify the bad chip. Mike Willegal

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Re: [vcf-midatlantic] Apple Branded Mid-80's Memory Compatibility Question.
by Ian Primus 08 Aug '21

08 Aug '21

Yeah. They're all the same part electrically, the same industry standard pinout. Tons of compatible part numbers.You can also use a 41256 or equivalent in a pinch, it just has an extra pin that isn't used on the 4164 for the upper address bit. And basically any RAM in that type is going to be fast enough for the 1mhz Apple IIc, so the speed isn't going to matter either. Be aware that on the Apple IIc, there might not be enough clearance to fit a socket depending on which chip it is, so check before soldering in a socket by stacking a chip on top of the soldered one, and see if it clears when you put it back together. I do see a lot of those Micron chips fail in Apple IIc's. -Ian On Sun, Aug 8, 2021 at 9:59 PM MikeWillegal via vcf-midatlantic <vcf-midatlantic(a)lists.vcfed.org> wrote: > > I have an Apple IIc with a bad memory chip. The chip is labeled 4264 without any dash number (speed) and branded as Apple. This is apparently a Micron 64k x 1 DRAM chip with industry standard DRAM pinouts. Does anyone know if I can use a 4864-3 that also appears to be an Apple branded Micron part? This most likely was pulled from a working 128K Macintosh many years ago. I could not find a Micron PDF for a 4864, but a Hitachi 4864 seems to have the same pinout as the Micron 4264. > > thanks in advance, > Mike Willegal

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Apple Branded Mid-80's Memory Compatibility Question.
by MikeWillegal 08 Aug '21

08 Aug '21

I have an Apple IIc with a bad memory chip. The chip is labeled 4264 without any dash number (speed) and branded as Apple. This is apparently a Micron 64k x 1 DRAM chip with industry standard DRAM pinouts. Does anyone know if I can use a 4864-3 that also appears to be an Apple branded Micron part? This most likely was pulled from a working 128K Macintosh many years ago. I could not find a Micron PDF for a 4864, but a Hitachi 4864 seems to have the same pinout as the Micron 4264. thanks in advance, Mike Willegal

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Mice!
by Herb Johnson 08 Aug '21

08 Aug '21

> On Wed, Aug 4, 2021 at 2:01 PM Christian Liendo >> >> You can bid on these and add them to the exhibit >> > Adam Michlin Wed Aug 4 18:44:39 UTC 2021 > They really do belong in a museum, but, alas, too rich for my blood. > https://www.youtube.com/watch?v=yXyPvhISkRQ Regards, Herb -- Herbert R. Johnson, New Jersey in the USA http://www.retrotechnology.com OR .net preserve, recover, restore 1970's computing email: hjohnson AT retrotechnology DOT com or try later herbjohnson AT comcast DOT net

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VCF Museum and Warehouse Update
by Tony Bogan 08 Aug '21

08 Aug '21

Good evening everyone. The VCF Steering Committee is pleased to inform you of some exciting updates involving our warehouse and museum! The warehouse is going to be moving to a different section of the building it is currently in, providing us with about 600 additional square feet over the space we have now. More importantly, this section has a better roof on it (no leaks!) a paved ramp to the entrance and access to a loading dock (albeit one that needs some love and attention) We will be moving into this new space in short order and will then begin the process of finishing and climate controlling the space. This is good news for all the VCF artifacts! Now for even more exciting news! As many of you know, our current museum occupies just under 1/4 of a section of the 9010 Building at InfoAge (specifically just under 1/4 of section 9010A.) Each full section is about 6800 square feet. VCF will be moving into section 9010B. All of 9010B. When all is said and done we will have over 6300 square feet of museum space or just over 4 times what we currently have! Additionally, 9010B accesses the main hallway that connect all the ‘H’ buildings together (referred to as “Broadway” by InfoAge) which means several things for us. People will be able to access our new museum once completed by simply crossing the street from the main building. This will eliminate them having to walk down the street and around the corner. People will also be able to enter our museum from both ends, so whether they are by the Model Railroad and Wireless Operators section, (Where our current museum is) or coming from the Military Technology Museum or the Electronic Warfare section they can access our museum. We are very excited about these changes and will be reaching out to all our members looking for volunteers to help clear and prep the spaces and make them ready for our artifacts and/or the general public, as well as raising the funds to make all of these things happen!! Stay tuned for more updates as the time approaches for us to start clearing 9036C (the location of our new warehouse) in preparation for the big move as well as working on 9010B for our new museum. We will need your help and support as we transition to our new locations! Tony Bogan On behalf of the VCF Steering Committee

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VCF East Related....
by Martin Flynn 08 Aug '21

08 Aug '21

Quick update: 1. VCF and CDL (Ken, Mona, Stephen, and myself) were working on the network prep for VCF-East. Ken and Mona wrapped up the installation of the fiber hangers on 9059 (this is for the fiber to 9032A) , Stephen and myself prepped the new data switch for 9032A. 2. The whole team worked on the data rack in the hotel basement as prep for upgrading the first floor WiFi. Picture of the last two weekends work in the hotel at http://compdecon.org/wp-content/uploads/2021/08/img_1382.jpeg 3. Our friends at Ubiquiti sent two more UniFi access points for the 9032A meeting room (UAP-AC-PRO-E-US) Martin

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OT: Looking for recommendations on new soldering station for vintage electronics!
by Bob Shuster 08 Aug '21

08 Aug '21

I'm looking for a recommendation for a new soldering station. I think it's time to retire my 40+ year old Archer soldering pencil - that I've had at least since I built my first TRS-80 Model I expansion interface, maybe longer! I'm looking for compact, with an auto-off feature, temperature controlled, and a variety of tips. Is this pretty much every current station? I'm looking at the Hakko FX888, or maybe the less expensive X-Tronic 3020? Mainly I repair or modify vintage electronics, but occasionally modern stuff where I need a finer tip and less heat. Thoughts/recommendations? Thanks. - Bob Shuster

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tantalum caps with a slit/cut down the middle
by Bill Degnan 05 Aug '21

05 Aug '21

I have a few boards with tant caps that have a thin slit down the middle of them. Looks like this was done at the factory, not a tear or a blown cap. early 90's. Normal? Bill

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What considers a good age for something?
by Gregg Levine 05 Aug '21

05 Aug '21

Hello! I have here a TRS-80 Model 102, it's been used to work as a terminal for a Pi device. I confess I had an idea for an exhibit at an upcoming VCF East event, in this case the Model 102 would again be a terminal for the Pi who would be using the PDP11 emulator from the SIMH community and an appropriate OS. I'm thinking one of the UNIX images from the TUHS crowd or BSD211 as well. ----- Gregg C Levine gregg.drwho8(a)gmail.com "This signature fought the Time Wars, time and again." The Doctor considered Perry Mason's words during the last fifteen minutes of the trial before the actual one blurted out the usual confession. In the end he concludes, "It was obvious, wasn't it Paul.", the Doctor announces. Paul just shakes his head. >From The Doctor and Perry Mason an unpublished Memoir.

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