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So here's an update. I cut off the bad capacitors as follows. I find this method much better as you don't have to worry about desoldering them. I cut them off using a wire cutter, making sure I didn't stress the leads. Then I desoldered them easily using a regular soldering iron: I...

So I have begun work on getting my IBM PS/2 P70 luggable computer up to speed (see my other thread: http://www.vcfed.org/forum/showthread.php?73381-IBM-PS-2-P70-8573-POST-161-163-after-replacing-battery). One of the common issues was the internal floppy drive not working. In mine, it will spin...

I recently came into a wonderful IBM PS/2 P70, which I have always wanted. I knew it had POST errors 161 and 163 on buying, and hoped this could be fixed quickly. When I first got it, it does a RAM check up to 8MB, and then shows POST errors 161 (CMOS configuration lost (battery has died)) and...

Recently, I switched on my Amiga 1000, with an internal Gotek floppy emulator. The Gotek didn't work! It was working perfectly about 6 months ago, and has been sitting on my desk under a home-made computer cover. I have a dedicated USB drive for it, and just leave it in there. So a little...

I have an IBM PS/2E Model 9533, which is an unusual variant PS/2 as it has an ISA slot. My goal with my ISA slot was to install an ISA Sound Blaster, so I researched what I could, and decided on a Sound Blaster 16 model CT2940. I bought it, and I was setting it up on my PS/2E. So my setup it...

Hello All: I am interested in putting a sound card in my IBM PS/2E 9533. This is the small pizza-box PS/2, which has laptop components in it to be a very early energy-star compliant computer. It's got a 486SLC2 25/50 MHZ CPU, 16MB RAM, and a single ISA expansion slot. It's a neat little...

So I was encouraged by the website calculator for 555-timer circuits, and found I had the components, so I built up a prototype. I used the following components: C1=0.1 µF R1=1 KΩ R2=120 KΩ which mathematically generates a frequency of 59.8755 Hz. with a 50.2 % duty cycle. This seemed...

About 1-2 months ago, I came into possession of a very nice Commodore B128 / C610. It has a 220/240V power supply, and I'm in the US, so I bought a transformer unit from ebay for about $30. When I got it, I tested it out, and it seemed to work fine. I wrote some simple BASIC looping print...

I just heard about TRS-80s zapping disks when turning on with a disk in the drive. I think it applies to the model III or 4. I tried an internet search on this, but couldn't find anything. Does anyone have more info on this? Do we know why this happens? Is there a fix? Thanks.

So I've been wondering where you guys get your prototyping boards? I generally work with the single-sided copper clad boards with individually ringed 0.1 inch hole spacing for all my stuff. RadioShack has a good board about 4"x6", and I pretty much use it exclusively. I cut it down to size...

I have a very nice Model 70, which I have been working on for a while now, and have it set up and running smoothly with a 2GB SCSI hard drive running off a Future Domain MCS-600 SCSI card. The only remaining thing I feel I need to do on it, is to connect up the hard drive light/LED, which is...

Hello all again. So I also switched my configuration to running off a CF card. With the old 1.1.5 BIOS, I copied everything on my hard drive over to my CF card, and I had my system running well with just my CF card as the master. So then I attempted to update the BIOS with the plan to...

Thanks for the input guys. So I opened up the internal datasette, and here are some pictures. Nothing looks odd to me. I checked the mechanism operating some of the keys. Pressing record with play presses on a long, funky slide switch, which seems to be pressed in fully by a metal tab...

Hey All! So I'm back and did some more testing this morning. I only have one working cassette that works reliably on these datasette players, so I recorded a sample program save from the working external C2N player, and then recorded a similar program save immediately after it on the INTERNAL...

Hello All. I am trying to bring my PET 2001-8 back up to health, and have been working through some memory and stability problems in another thread. I have discovered load problems in doing that, mainly with the internal datasette. I thought I would start a new thread for this problem. So...

So this is really strange. Tonight I modified the memory test program, removing all the unnecessary bulk, and trimming it down to its functional components. Here is the complete memory test program: Here is a sample successful execution: Here is a sample failed execution: Here is a test...

OK, cool idea. Actually, I have some mini-grabbers that I can use on the IC pins of D9, so I'll use those for the reset. Thanks! --------------------- So I also did a bit more testing this AM. I reseated all the RAM chips and most of the socketed ICs, and retested with my looping PRINT...

So I did some specific testing. I ran 3 tests, varying what I printed with each one. In each case, I ran the looping BASIC program, and they generally garbled in 1-2 minutes of looping. It's interesting to see the characters garble up a few iterations before the program crashed. In each...

Hello All. I have a chicklet PET 2001-8, which I got about 6 months ago. I only got around to testing it for real recently, and have discovered some stability issues. When I first got it, I just tried typing some short BASIC programs, and running them, and it seemed to work fine. The...

Hi All: Has anyone seen an Apple II monitor stand like this one? http://www.ebay.com/itm/181891865482 It looks like the rubber legs are different (round), and the pattern of supports on the underside also looks different. Outside, it looks like an apple product. Looks very similar to the...