YARC - Yet Another Retro Channel

I could just about cry. Get ready for a long tale of woe.

Since my last video on the Apple ][ Plus, I decided I hadn't done it justice. I wanted to show the most common expansions purchased for the II+ BITD. However, I didn't have some of them and other things I did have weren't the most common. So I went on a spending spree and bought a bunch of stuff. One of the things I bought was a Disk II 5.25" floppy drive.

It arrived a few weeks ago. I was actually expecting it to be faulty, what with the age and how easy it is to misalign the ribbon cable pins and send +12V into the wrong part of the analog board, so when I plugged it in, it didn't surprise me that it didn't work. What did surprise me was that it caused the power supply to go into protection mode and the II+ wouldn't boot at all. Now, this wasn't the original PSU. After I fixed the original PSU the first time by recapping the whole thing, it eventually failed again and I haven't gotten around to fixing it a second time, so I was using a PicoRC power supply. A neat little board that lets you use an ATX power supply, normally a PicoATX. They're available for several different retro machines and I have the Apple II version.

So, I've spent the better part of 3 weeks troubleshooting this damn thing. Note, I didn't have a known working drive for comparison or to pull working parts from to test with.

As most of you will know, when your power supply goes into protect mode on a machine that HAS a +12V rail, the first thing to suspect is a short on that rail and the first suspects are tantalum capacitors. Those little teardrop shaped blue or orange bastards are almost as much of a menace as Varta batteries or Rifa caps.

On opening the drive and inspecting, I found only a few tantalums on the motor speed control board and none on the analog board. I tested all of them and not one was showing a short. DAMN!


OK, lets see if the problem is the analog board or somewhere else. I disconnected the card edge connector that connects the motor speed control board, the spindle motor and the head stepper motor to the analog board then reconnected the drive to the Apple and retested. Sure enough, that worked and the Apple booted, but, of course, the drive didn't work.

Fine, let's see if it's a problem with one of the motors. First, I tested the spindle motor. The spindle motor has a +V and ground connection along with the two leads for the tachometer. Here's where I made a rather basic mistake and demonstrate how bad I am at analog electronics. I tested for continuity between the +V lead and the ground lead, thinking that a short there might explain things. Of course, I read a continuous path. Took me almost a day and lots of faffing about with motors stolen from a couple of SA-400 drives I had lying around before the bells went off and I remembered that the +V and ground leads on the motor are a COIL used to energize the electromagnet and, therefore, should definitely always have a continuous path and the original motor was probably fine. Sure enough, when I checked it using my bench power supply, the motor ran as it should. IDIOT!

Right, what else. I started checking other caps on the motor speed control board. There are three 10uf 35V caps that mostly have to do with providing the reference and tach signals to the speed controller IC. All three tested in the nf range in circuit. I didn't think these should be the cause of the problem, but I was getting desperate, so I ordered replacements, waited for them to arrive, then fitted them. While doing so, I retested the old ones out of circuit and they looked good, but I replaced them anyway. Still no luck.


Next, I tested the four transistors on the board by pulling them and checking. All four looked good, so I put them back. Finally, I checked all the diodes. They were good, too. I didn't test the resistors because they weren't likely to be the problem and I'd have to pull at least one leg of each to test them out of circuit. Apart from a couple of other parts that weren't related to power delivery, that was everything on that board. It all looked good.

I'd recently watched a couple of Adrian Black's videos related to the Disk II drive, though, and something he pointed out looked like it might be helpful. Turns out what I thought I knew about the Disk II, that they were Shugart mechanisms with Apple electronics, wasn't necessarily true. In fact, it looks like they were actually Alps mechanisms, extremely similar to the mechanisms in the Commodore 1540 and early 1541's, to the point that the motor speed control boards and the spindle motors themselves are the same on both, with the only difference being the form factor of the speed adjustment potentiometer.

Well, I had a 1541 Alps sitting around waiting on a cleaning / restoration, so I scavenged it for its motor speed control board and swapped that into my Disk II drive. When it was all hooked back up, I tested and got the exact same symptom. Now, assuming it to be exceedingly unlikely that I had two motor speed control boards with the exact same fault, I had to assume the MSC board was fine. That left the problem to be somewhere on the analog board after all. The +12V passes through the board and there are a few components that might be at issue.


Of special interest was a ULN2003 darlington transistor array. I'd heard that that chip is one of the ones likely to be damaged if the ribbon cable is misaligned. I didn't have a way to test that IC and I didn't have any spares, so I ordered some and again waited. When I got them, I replaced the original and retested. Same symptom again. I tested the 74LS125 buffer IC in the TL866, but it tested OK. There's another transistor array (not darlington this time) which I ordered some replacements for, but they haven't arrived yet. As you'll see later, that didn't turn out to be the problem anyway. I also ordered a replacement for the read amplifier IC (MC3470P), but again, that won't turn out to be the issue.

Now I'm nearing the end of my rope. I verified the two transistors on the analog board, checked some more capacitors, but couldn't come up with anything. I did make one discovery. The short only appeared when the spindle motor was trying to start up during power-on.

Now I'm thinking "what if the problem isn't in the drive at all, but somewhere on the motherboard?"


So I start checking everything there. There are a few tantalum capacitors on the Disk II controller card, so I checked them, but no luck. I wouldn't expect them to be the problem anyway as the short is intermittent. I also have a Yellowstone controller card (a modern card allowing you to use more than just Disk II drives on an Apple II), so I tested with that and still got the fault.

Well, today I received the second Disk II drive I had ordered after all kinds of USPS delay, so I hooked that drive up and got the EXACT same failure. That can't be a coincidence, so the problem MUST be on the motherboard or the PSU. Now, I hadn't considered the PSU because it was a modern device and it had been running everything else just fine no mater how many expansion cards I had installed. But now I was grasping at straws. So, I pulled the PSU out of my Apple //e and fitted it to the II+.

I'll let the suspense mount for a moment.....






The Apple ][ Plus fired right up and the second disk drive ran as it should.


Next, I needed to figure out if the problem was with the PicoRC board or the PicoATX power supply I was using. I dug out a 450W ATX PSU and hooked the PicoRC up to it, then connected the II+. Worked like a champ. I can still recommend the PicoRC power supplies.

Where did I go wrong? I bought a cheap PicoATX power supply through Amazon. It was supposed to be rated at up to 150W, which should be plenty for the Apple ][ Plus and all its accessories, but it clearly wasn't. I've now ordered one of the PSU's recommended by the original creators of the PicoRC, which look a lot beefier on their website than the one I got. Moral of the story, don't cheap out on Amazon shit when it counts.


And now you know why I haven't put out a video in such a long time. Sorry, I needed to vent after all that.

6 months ago | [YT] | 4

YARC - Yet Another Retro Channel

Just a reminder:
Tomorrow, October 19th, 2024 at 6am EDT (11am BST), More Fun Making It, Lee, and a bunch of his YouTube creator pals will be going live for a 12 hour long live stream event to promote the charity auctions being held to support The Befriending Scheme.
The Befriending Scheme is an organization that provides opportunities for vulnerable adults in and around the Suffolk area in the UK to build friendships and learn valuable skills. Lee's family have been touched by this organization personally and this is his way of giving back.
Last year, Lee and a bunch of his friends held a similar event focused on Sinclair computers. This year, it's Commodore's turn.
Loads of really cool Commodore machines are up for auction. There's everything from a KIM-1 replica up to an Amiga 1200 in a snazzy Checkmate case and everything in between.
I've got a C64 in the auction, in case you want to buy something I've featured on my channel and I'll also be appearing as a guest on the live stream somewhere between 2pm and 4pm EDT (7pm - 9pm BST).
Links below. And we'd love for you to all come join us on the live stream.

Just Giving page for those who can't afford to buy one of the lovely items up for sale, but who still want to help out:
www.justgiving.com/page/mfmi2024

The live stream has to be in two parts due to YouTube limitations:
youtube.com/live/IX30UTj5tmo?feature=share
youtube.com/live/S6NCgi9FLsk?feature=share

Here are a couple of pages where you can find links to the eBay auctions:
www.morefunmakingit.co.uk/ebay2024/
www.morefunmakingit.co.uk/youtubers-ebay-listings/
and here's Lee himself describing the auction items:
https://www.youtube.com/watch?v=nQ4Q1...

Here's my video on the C64 outfit I'm selling:
https://youtu.be/GRvqWRLxiUM
and the live stream where I repaired it:
youtube.com/live/ADFGHkxKjaE

Thanks! and we'll see you tomorrow on the livestream!

10 months ago | [YT] | 1

YARC - Yet Another Retro Channel

I need to give you all an update regarding the family health issues I've been dealing with lately and that some of you are aware of. I'm doing this because it'll impact my YouTube time and I want you to know what to expect. You've all been very supportive to date and I've really appreciated it. Again, I'm not fishing for sympathy.
My father passed away the morning of August 5th. We're coping OK. I'm doing my best to support my mother and help her make his final arrangements.
After his funeral and a period of mourning and adjusting to his absence, we'll need time to deal with the estate and get my mother and sister settled into a smaller home. My parents collected antiques for over 50 years so there's a huge collection we have to address. It's going to take a good deal of time.
I will, of course, need an outlet during all this, so I'll still slip away into my lab from time to time to play with my toys and burn off some of the stress. I may, on occasion, record some of that. So I don't expect to be 100% gone from the scene. I'm just going to be continuing to put family first. After all, I love my tinkering and this community but it's a hobby.
I know you folks will understand. You've been really great so far and very patient with me. You don't know how much that's meant to me.
I'll try to provide updates now and again so you know how I'm doing.
Thank you.

1 year ago | [YT] | 13

YARC - Yet Another Retro Channel

The finale of the 2024 Commodore 64 Repairathon goes live tomorrow morning, Saturday 27 July, 2024. If you haven't watched the earlier episodes, here's a link to the playlist:

https://www.youtube.com/watch?v=Wb0K2...

1 year ago | [YT] | 3

YARC - Yet Another Retro Channel

Hi, everyone. Many of you will have noticed my conspicuous absence lately. I apologize for that. Those of you who have been around a while will know that my parents are both feeling the effects of extreme overexposure to time and that I've been providing them with all the support I can. As I've said before, I love them and I'm grateful that I'm in a position where I can help them when they need me, but sometimes that gets to the point where it monopolizes my life and that's what's been going on lately. I'm behind on everything right now. If I'm lucky, I may have a few days to try to catch up a bit, so I'm working on my household chores and maintenance, trying to get the lab reorganized and tidied so I can record part 5 of the repairathon, making some necessary upgrades to my lab PC, catching up with Discord, catching up on watching other channels' videos, and trying to get some rest in the middle of all that other stuff. I really appreciate your patience. Family first, right? You'll hear from me soon, I promise.

1 year ago | [YT] | 13

YARC - Yet Another Retro Channel

3 machines done, 7 more to go. Part 1 should drop Saturday, 20 April, 2024.

1 year ago | [YT] | 7

YARC - Yet Another Retro Channel

Today's my birthday, folks. And I plan on torturing myself with what I expect will be a frustrating, infuriating, and tedious Apple ][ Plus keyboard repair. Do I really hate myself that much?

1 year ago | [YT] | 7

YARC - Yet Another Retro Channel

I feel a sense of accomplishment today. I actually managed to figure out how to bring a guest into OBS using vdo.ninja. Took me a while. It's not as straight-forward as the folks on YouTube make it out to be.

Watch me try it out live during the Commodore Livestream on Sunday, October 29th, 2023 @ 1pm EDT / 10am PDT / 7pm BST when I bring Patreon supporter Brian Bommarito on to help me fix a couple of 250407's (breadbins) and a 250466 (64C).

Then I recorded a new video for Wednesday. This one is Livestream related. I'm doing the initial examinations of the machines we'll be trying to fix on Sunday. Watch for that video to be released, hopefully before noon Wednesday, October 25th.

I hope to see all of you on Sunday!

Todd

1 year ago | [YT] | 3

YARC - Yet Another Retro Channel

Hello again, everyone,

Regarding the livestream contest, the original winner never responded to my attempt to contact him, so I've selected another name.

Congratulations to Brian Bommarito for being selected. Again, I've reached out to Brian to confirm and I'll update you when I hear back from him, whether he accepts.

Todd

1 year ago | [YT] | 6

YARC - Yet Another Retro Channel

Thank you all!!! Let's keep it going.

1 year ago | [YT] | 6