The Adventures of a Timid Tinkerer aka LC475 upgrades

yock1960

Tinkerer
Mar 24, 2022
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18
Timid is perhaps unfair, but not wholly so...in any case, I've decided to start a new thread to recount my experiences in performing upgrades to my LC475.

First some history. I'm not perhaps the typical Mac enthusiast, starting my computing journey back in 1985 with a C64. I used Commodore 8 bit computers into the early 90's before moving into the PC realm. For brevity, I will say that somewhat by accident, I had a couple of years foray into the Mac world; 128K, Plus, Classic II and finally an LC475. This enabled me nearly exclusive use, while my boys gamed on the PC. Getting into used 68k Macs at the time was affordable, I even bought a PPC card for the LC475. I never went beyond this however, as new Macs were still too pricey for me...I could build my own decently powered PC much more affordably. Eventually, the Mac phase passed and everything was boxed up and stored away.

Fast forward to today. Somehow, I never got rid of much of the Mac stuff I had accumulated, although I did sell the PPC card (dangit!). Since I'm retired now, I recently had my Mac interest rekindled from watching YouTube videos. I've spent the last 5-6 weeks going through boxes, buying bits of hardware and trying to remember how to use these things (accelerated Mac Plus and LC475). Mostly this has been modern sd card replacements...floppyemu, SCSI2SD and BlueSCSI and then I saw JDW's video on Kay Koba's Spicy O'clock overclocking board.

I ordered one ASAP. Then, upon taking a closer look at the install instructions, I noticed that I had badly misinterpreted step 1. It's a little embarrassing...perhaps it was past my bedtime...anyway, I think I thought it meant...don't use this chip and I thought, 'no problem, I won't', but it really meant don't use the chip on your mainboard, replace with this one! Uh oh! 😱

I'm not much of a soldering guy. I've done some over the years...badly. I felt that I would be able to remove the resistor required, and solder the connecting wires...but removing a 20 pin SMD IC and then soldering in another?! 😳

I soon discovered this forum and posted a question about this and learned that the mod would still work with the original clock generator (MC88920) but be rather limited at the top end of the overclock range. In the intervening time, I ordered recapping kits for my LC475 and power supply and dug out some old PC mainboards and interface cards to destroy...err...practice on...both! 😑😄

Spicy arrived over the weekend and I successfully installed it, sans clock generator swap. True to what Kay Koba told me, 39mhz is about as high as I was able to go. Even so, this is a great product for the community and I'm extremely happy with it!

In the coming weeks....months...??, I'm going to attempt to recap my power supply and logic board. I don't consider it a sure thing, but watching hours of YouTube videos, purchasing more gear and practicing, has me better equipped and cautiously optimistic! I even have 2 MC88196DW80 in transit!

I'm still doing a bit of tinkering with the current setup and have already had some...interesting...benchmark results. My next step, before recapping, will be swapping the BlueSCSI for the SCSI2SD that is installed in the Plus and rerunning benchmarks. I want to see which is the best performer for the LC475. Your words of encouragement or kindly meant advice, are welcomed!

Stay tuned! 🙂
 

yock1960

Tinkerer
Mar 24, 2022
65
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Well, I spent a couple of hours today, reading up on how to setup multiple devices on a SCSI2SD and use an emulator, 'dd' and Balena Etcher to setup your files. This still defeats me. It's easy enough to configure the card using the SCSI2SD utility, but when I tried to go to my LC475, to initialize and partition, the 'drive setup lite' didn't like more than 2 devices or drives larger than...
well, large drives. I don't have a physical cdrom drive for the Mac anymore and there was nothing on the floppyemu appropriate either. 😑 After some head scratching I attached the BlueSCSI internally and got the external SCSI enclosure that I use for the Mac Plus, hooked it up with the SCSI2SD with a 32mb card with 2 14gb drives. Problem solved...well...it's ongoing. After I got the SCSI2SD working, I ran some quick test. I love the simplicity of BlueSCSI, but SCSI2SD is significantly faster. I will still have an issue when I want to move large files over...nothing that a little money won't fix though. 😏

Once I'm done copying drives and have the SCSI2SD booting the system, I'll do some full benchmarking and post the results.
 
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Eric's Edge

Tinkerer
Oct 31, 2021
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Well, I spent a couple of hours today, reading up on how to setup multiple devices on a SCSI2SD and use an emulator, 'dd' and Balena Etcher to setup your files. This still defeats me. It's easy enough to configure the card using the SCSI2SD utility, but when I tried to go to my LC475, to initialize and partition, the 'drive setup lite' didn't like more than 2 devices or drives larger than...
well, large drives. I don't have a physical cdrom drive for the Mac anymore and there was nothing on the floppyemu appropriate either. 😑 After some head scratching I attached the BlueSCSI internally and got the external SCSI enclosure that I use for the Mac Plus, hooked it up with the SCSI2SD with a 32mb card with 2 14gb drives. Problem solved...well...it's ongoing. After I got the SCSI2SD working, I ran some quick test. I love the simplicity of BlueSCSI, but SCSI2SD is significantly faster. I will still have an issue when I want to move large files over...nothing that a little money won't fix though. 😏

Once I'm done copying drives and have the SCSI2SD booting the system, I'll do some full benchmarking and post the results.
Awesome to hear from another retro user!

I was using an older V5 SCSI2SD but found the setup and management too much work. I've switched to using BlueSCSI exclusively having sold the SCSI2SD adapter. The BlueSCSI firmware is improving. There is a beta release that just dropped that has a 10% speed improvement.
 
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yock1960

Tinkerer
Mar 24, 2022
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Hi _SDGOL_,

Yes, BlueSCSI is wonderfully easy to setup/manage but I'm on a bit of a speed kick here and I think I'm about to the point where I'm not going to be adding alot more software...I think 🙄.

I saw there was an update, but that requires some extra bit of hardware, doesn't it?

I will probably pickup another BlueSCSI...after I make sure this one will work with the Plus and use it to perform file transfers >1.44mb, unless I can figure out a way to use the floppyemu for that.
 
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Eric's Edge

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Oct 31, 2021
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Hi _SDGOL_,

Yes, BlueSCSI is wonderfully easy to setup/manage but I'm on a bit of a speed kick here and I think I'm about to the point where I'm not going to be adding alot more software...I think 🙄.

I saw there was an update, but that requires some extra bit of hardware, doesn't it?

I will probably pickup another BlueSCSI...after I make sure this one will work with the Plus and use it to perform file transfers >1.44mb, unless I can figure out a way to use the floppyemu for that.
Totally understand. You do need to flash it which requires a $10 tool. I haven't taken the time yet.
 

yock1960

Tinkerer
Mar 24, 2022
65
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So today I recapped my power supply, it even worked after I was finished! But before I did that, I ran benchmarks. The first two images show results from MacBench 1.0. I ran it because it includes more 68k results. While it did not have an LC475 or Q605, I used the Q700, which is at least a 25mhz processor, if a full one and gives a pretty good indication of the overall increase of performance versus a stock 25mhz machine.

The current system is my full 68040 LC475 Spiced to 39.19mhz and with the SCSI2SD, the other two are pre Spicy, BlueSCSI, one with and one without fpu. The SCSI2SD scores are much better.

The last image is results from MacBench 3.0. From the included test results I picked the Q630. I don't see any point in comparing to a PowerPC machine. I wish there were more to choose from....maybe I can find some. It shows a similar story in regards to SCSI2SD vs. BlueSCSI.

Next up is the logic board recap. o_O I think I'll do more practice first....I found an old WinTV-PVR card with the same style/size capacitors on it, in my old parts box. I've already gotten some off succesfully, prior to ordering a hot air rework station. No way to replicate nearby plastic parts however.


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yock1960

Tinkerer
Mar 24, 2022
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Well, that was exciting! 😳🤣 I just finished removing the caps from the logic board...with a hot air rework station....even though I had watched numerous videos...I was not prepared! Now I know why people do twist and pull! The stink doesn't help, neither does the too close plastic parts...small amount if melting on the power connector...don't think it's a big deal. Must not have had the shielding all the way down.

On to the next step!
 
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Eric's Edge

Tinkerer
Oct 31, 2021
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Well, that was exciting! 😳🤣 I just finished removing the caps from the logic board...with a hot air rework station....even though I had watched numerous videos...I was not prepared! Now I know why people do twist and pull! The stink doesn't help, neither does the too close plastic parts...small amount if melting on the power connector...don't think it's a big deal. Must not have had the shielding all the way down.

On to the next step!
I don't have a hot air station so I use the snip it in half and deconstruct it from the top down technique. I tried the unsolder each side and gently lift technique and had less success.
 

yock1960

Tinkerer
Mar 24, 2022
65
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So, the recap was successful, but, not without some drama!

First, I'll reiterate that I have Kay Koba's Spicy O'clock installed, which calls for a MC88196DW70 or MC88196DW80 installed, not the MC88920 in a stock LC475. I have been able to get to just over 39mhz with this combo. It wasn't perfect, taking a few power cycles to boot from cold start, but stable after that.

When I put the logic board back in and turned it on, I got an unhappy Mac chime, followed immediately by a happy mac chime and then what seemed like a too long memory check delay (128mb ram installed), so I shut it off. On subsequent restarts, I never got the bad chime again and I had to turn Spicy down to just under 37mhz to boot reliably. I think that this is also the 'reliable' always boot setting for before recapping, it's just that it was pretty easy on the on/off switch, to get it to go just a little faster. There's probably a technical reason for this...I just have no clue as to what that may be!

The other odd thing, is that at boot, after the screen comes on and I get the happy Mac icon, it goes black for a second, then comes back on, happy mac again, then boots. It never did this at any point before recapping.

Other than that, all appears to be working. Now I'm just waiting for my MC88196DW80 chips to come from China!
 

pfuentes69

Active Tinkerer
Oct 27, 2021
380
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Switzerland
The other odd thing, is that at boot, after the screen comes on and I get the happy Mac icon, it goes black for a second, then comes back on, happy mac again, then boots. It never did this at any point before recapping.
I get this sometimes with the RASCSI, and I'm pretty sure also with the BlueSCSI.
 
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yock1960

Tinkerer
Mar 24, 2022
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I get this sometimes with the RASCSI, and I'm pretty sure also with the BlueSCSI.
Very interesting...as Arte Johnson would say ( gawd I'm old 😳😄)! You got me thinking. I use a v5.2 SCSI2SD now, have used v1.1a BlueSCSI, neither exhibited this behavior prior to recap...as I have said. Anyway, I disconnected it. Guess what? No screen blanking! Seemed to take an inordinately long time to show the 'feed me' icon, but I don't really know what's normal. I'm going to fetch BlueSCSI and attach it, to see what gives.

Stay tuned!
 

yock1960

Tinkerer
Mar 24, 2022
65
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Curiouser and curiouser! 🤔 Attached the BlueSCSI and no screen blanking, but it hangs at boot unless I don't load extensions. More experiments to come...don't touch that dial! 😏
 

yock1960

Tinkerer
Mar 24, 2022
65
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I went and found my molex power connector to feed 5v to these devices, BlueSCSI first. It booted right up, no screen blanking! Next up SCSI2SD, it took longer than normal to boot and still had screen blanking.

I have this monitor (Digital Doc 5) from my PC overclocking days...back in the late 90s/early 2000s, that connects to power through a full size molex connector. It monitors the 5v & 12v rails and can monitor up to 8 fans and thermocouples. Voltages show good, from the 4 pin connector near the SCSI connector...but, C105 did check shorted when I was prompted to check my work for shorts on another thread. When I took it back to the bench however, the short was gone, but, I found a solder blob near C150. Sheesh! There must be a connection, but I don't know what.
 

pfuentes69

Active Tinkerer
Oct 27, 2021
380
293
63
Switzerland
I’m not sure, but the false boot could be related to having multiple bootable disks. At least that’s the conclusion I got with the RASCSI.
And the long delay I’d say is normal with 128MB of RAM.
 
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yock1960

Tinkerer
Mar 24, 2022
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I’m not sure, but the false boot could be related to having multiple bootable disks. At least that’s the conclusion I got with the RASCSI.
And the long delay I’d say is normal with 128MB of RAM.
Well I'll be! Who wants to guess the reason for the...odd...behavior? You Mac gurus will probably know...😄

If nobody 'guesses' before then, I'll post the answer this evening. Problem solved!
 

yock1960

Tinkerer
Mar 24, 2022
65
24
18
On another topic, what's a good material to use to reattach broken case parts? Acetone isn't cutting it on the fan clips.
 

yock1960

Tinkerer
Mar 24, 2022
65
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Okay, so the cause of the boot 'screen glitch' was that the boot disk scsi id was 4. I changed it to zero and the glitch disappeared. Perhaps scsi id 1 would also work...I'm not really interested in seeing where the limit is, just happy that it's not an artifact of my recap job!
 

yock1960

Tinkerer
Mar 24, 2022
65
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Incidentally, I did more experiments on whether BlueSCSI or SCSI2SD was more amenable to overclocking in my machine's current state...there's no perceptible difference. I had hoped to throw my last used physical drive in the mix, but sadly it appears to have given up the ghost in the short time that it has been retired! Perhaps I was incautious and mishandled/zapped it. I have a few more drives about, but none currently bootable on this machine and it's more work than I'm interested in doing to get them ready.
 

yock1960

Tinkerer
Mar 24, 2022
65
24
18
While waiting for my clock generator chip to arrive, I've been messing around with heatsinks. Ever since swapping my stock LC68040, with a full MC68040, I had been using a slightly too large, 16.5mm tall, aluminum heatsink, with Arctic Silver 3, thermal compound. In preparation for, hopefully, higher clock speeds, I decided to try a fan on top of the heatsink, that meant a different heatsink. I've accumulated a number over the years and settled on one that had a central recess, just for a fan. The original fan is long gone, but I found a 40x10 fan. The top of the pizza box just rests on top of this, but I can snap the case shut! Unfortunately, this starves the fan. Case off, at ~40.5mhz and measured with a thermocouple slid into the heatsink fins, it runs at about 31.5C, with the case on, this jumps up to 39C (running Doom demo mode) .which still is reasonable. Without a fan, measured temperatures would run upwards of 45C and run hotter with the case off.

Another thing I may have learned, although it's too soon to say if it will hold true in the long run, is that while any given startup may hang, when booting from the SCSI2SD, if I boot from a floppy (which seemingly always boots) then restart from SCSI, it boots. Why this is, I don't know, but it seems to be a workable method
 

yock1960

Tinkerer
Mar 24, 2022
65
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Ever since I connected an old digital monitor, designed for use in a 5.25" drive bay, by running wires through the PDS external 'port', I've been able to monitor my power supply voltages and by using thermocouples, internal temperatures...mainly the CPU. The voltages have never been rock steady, which I attributed to the PS needing recapped. They also were rather high for 12V. This monitor allows setting a tolerance for when to throw an alarm. The alarm would be tripped fairly often, but sporadically...some days not at all. After recapping the PS, reported voltages improved, but not stability. Today, I hope I figured out the cause. I connect this monitor by connecting to the HD molex connector, since I no longer use a spinning platter HD. To give a little more room to place the monitor....without 'stretching' the wires, I added another molex connector. Today I removed the extra connector, which seems to have helped. Time will tell! 🤞
 
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