Mystic Overclock - A Spicy O'clock Adventure

[Drake]

The worlds MOST handsome man @Kay K.M.Mods sent his amazing product "Spicy O'clock" all the way from Japan to Canada for me to experience and share results.

Kays Original thread: https://tinkerdifferent.com/threads/spicy-oclock-project-has-started.128/#post-4410
Purchase Here: https://en.infinityproducts.co.jp/product-page/spicy-o-clock

The top view of the Spicy O'clockunit itself. An adjustable oscillator designed for 68040 based machines.
The adjustable oscillator let's you fine tune the clock speeds to achieve stability and functionality. If you do not have a multimeter or oscilloscope capable of reading frequency then measuring the resistance (while the machine is off) is a second method of determining approximate speeds. You can find Kays chart matching resistance to speeds here: https://ameblo.jp/keroxiee1016/entry-12717260184.html

My Mystic (LC575) board is host already to custom VRAM reverse engineered by @Stephen with designs silkscreened by myself, These sticks are using 60ns chips which have proven to assist in overclocking speeds of up to 50mhz.

A detailed view of the solder points for LC575, Pin 8 of of the clock buffer/driver must be lifted to hijack the clock output signal allowing you to adjust your frequency.
Black - GND
RED (VIN) - +5v
Yellow - OUT

In this image I am using my meters frequency setting to measure the oscillators output at 18.5mhz, because our bus speed is double this means our CPU will be running at close to 40mhz, in this example it was identified as 44mhz (let's assume the machine rounded up). I did some fine tuning to keep it sitting at 40mhz afterwards.

I used Speedometer to do a quick bench test and used these results to make comparisons between it and the 40mhz Macintosh Quadra 840A/V.
If I were to replace my 68040 with a "full '040" I'm certain these results would be slightly above the 840 spec.

For curiosity sake I did measure the CPU heat output with the overclock running and the camera did show 39.2 degrees with a passive heatsink, I'm certain this temperature is more than safe if not the same as a stock unit without heatsink.

The Spicy O'clockis simple, affordable and easy to install! While I'm sure some users wouldn't dare experiment with their machines; I felt testing this product goes hand in hand with the fundamentals of Tinker Different. Finding new ideas, exploring them and implementing them together!

I will be looking forward to trying Spicy O'clockon other 68040 machines soon, LC475, Centris 650 maybe even Quadra 950!

 

[Kay K.M.Mods]

Thx Drake, One of your experiments has become my legacy! In addition, in my experiment your VRAM could withstand up to 51MHz. The VRAM of the same PCB I made is up to 46MHz for 70Ns.
Overclocking and all bus timing are incomplete on this low cost Mac, so there are limits to the clocks at which serial and PDS work perfectly, but these experimental results will soon be uploaded to YouTube by @JDW . I want him to focus on video production, so I'll wait for his video and post it.

SpicyO'Clock! contains various other elements. The one I set up supports up to 38-51MHz, but I'll post later how to set it to other frequencies. This means that it can be a substitute for poorly available oscillators such as 15MHz.

Arigato Drake-san, Let's continue to enjoy various Geek's items, Cheers!

 

[Drake]

一緒に成功することができます！ スティーブンについて冗談を言いましょう

 

[Kay K.M.Mods]

一緒に成功することができます！ スティーブンについて冗談を言いましょう

あなた達は冗談しか言わないDudeです

 

[JDW]

I am still working on my Mystic 640x480 Mod video right now, but after that I will do the Spicy O'Clock video. I've been working with Kay on the topic of overclocking for quite some time now, and the overclocking speeds are surprisingly good. But it all depends on VRAM, plus my SECRET SAUCE.

Interestingly, when I overclocked to a speed that was too high, I was still able to hear the internal HDD boot, and when I press the power key and hit return, the Mystic shuts down just fine. But the CRT displays a rolling blue pattern. Since it boots, that means the CPU can handle the excessive clock speed, and obviously the RAM can handle it too. If either CPU or RAM could not handle the very high clock speed, it would not boot. But the display goes crazy when the clock speed is too high, which implies that even the 60ns VRAM is not quite fast enough for very high overclocks of 49.5MHz and higher. But even if 50ns VRAM chips existed, I'm not sure how much higher the clock speed can go on the LC575 motherboard because the RAM is 50ns. And obviously, the CPU will have its upper limit at some point too.

I was able to reach the same high clock speeds with Drake's 60ns VRAM and Mr. Fahrenheit's 60ns VRAM. Since Mr. F. very kindly sent me 4 sticks of 60ns VRAM for testing, I sent 2 sticks to Kay (after testing), along with Drake's 2 sticks (after testing) because he has many more vintage Macs than I do in which to test the VRAM. I retained the other 2 sticks of Mr. F's VRAM to use in my Mystic. But again, in my testing, all 6 sticks of VRAM gave me the same performance across 3 CPUs tested (1 of which was the stock LC version 33MHz rated 040). The LC version chip wouldn't clock as high as the CPU Mr. F. sent to me, or the CPU I got from UTsource, both of which are the full FPU version chips.

All this and much more will be present in my overclocking video. It should be fun and ground-breaking too. I still remember when I broke 49MHz and Kay responded, "You have the world's fastest Mystic!" After much Googling, I found no mention of clock speeds that high in the past, so we really have broken new ground with this 60ns VRAM. Without that, clock speeds would be capped much lower.

My humble and sincere thanks to @Kay K.M.Mods , @Drake and @Mr. Fahrenheit for kindly shipping me items that made all this possible. I've spent weeks testing to ensure stability, and I wanted to do all that testing before my VGA mod to ensure the benchmark numbers I got before the VGA mod would be maintained after the mod. That's because the power supply will be taxed a bit more. And if your wondering, yes, there is a SECRET SAUCE to get very high clock speeds, and it's not only 60ns VRAM. Motherboard capacitors matter. And nope, the ESR of new solid tantalum caps won't get you to Overclocker Heaven! Kay confirmed that by using the same caps I did, and only then did he achieve the highest possible speeds. Again, this will be mentioned in my video when it comes out. Stay tuned!

 

[Kay K.M.Mods]

I will put a link of my blog, how to replace oscillator. *excluded SpicyO'Clock

『LC575 overclocking and 70Ns VRAMS』

Oct 24, 2021 correction:In the text, it says that the chip was replaced with a …

ameblo.jp

About a Spicy O'Clock! is here

『What kind of device is "Spicy O’ Clock!" ?　』

Spicy O’Clock! Developed for 68040, Spicy O'Clock! Is a silicon oscillator un…

ameblo.jp

 

[Action Retro]

Just chiming in to say that this is so incredibly cool!

 

[Drake]

@JDW I can't wait to see the video with all the progress you've been making on your Mystic!
I feel like soon there shall be a trophy that passes to the user with the fastest Mystic So maybe it is a race?!

@Action Retro thank you! You must have seen the Jurassic Park desktop icon from a mile away!

 

[MacinJosh]

Sweet! This is what I'm working toward on my Mystic. Does anyone have a source for 60ns or 70ns chips so I can build my own VRAM?

Josh.

 

[JDW]

Does anyone have a source for 60ns or 70ns chips so I can build my own VRAM?

It very well could be that @Mr. Fahrenheit and @Drake purchased the last of the world's supply of compatible 60ns chips! ;-) Perhaps they would be willing to share their respective experiences.

 

[Drake]

@JDW I tried my best the last 2 days to catch you!

I removed the Kemet tantalum capacitors for lower ESR and stability BUT... I think I have a limitation regarding my LC33 that keeps me at 49mhz and no further!

Frequency readout displayed here at 24.420mhz. While it is MOST stable at 48mhz the machine can almost touch the 50mhz mark with some bus errors. Interestingly I also tried using an RC25 CPU in this logic board which was stable to 45mhz! which makes me hopeful that I may be able to find an RC40! (if any legitimate ones appear online).

The CPU itself also remains cool in this state using a stock cooler from quadra700.

You may rest easy up in the clouds of 50+mhz heaven my friend!

 

[JDW]

Thank you for posting your findings.

The CPU I’ve been testing was purchased from UT Source and claims to be a 40 MHz rated 68040, but the markings came off very easily so I believe those markings are fake. Even so, when I’m about to say applies to that particular CPU, which runs at about 60°C or lower in my testing, with 45mm aluminum heatsink.

I actually was going to let the cat out of the bag when I release my Overclocking video because it’s hard to announce that I have the world’s fastest Mystic but everybody else is already starting to have the world’s fastest Mystic! But I’m still doing extensive testing before I commence filming.

I spent many days of testing prior to the VGA mod know that I could stably reach 49.29 MHz, but I now need to repeat that testing after the VGA mod to ensure there are no differences.

But I have discovered there are differences. And for some reason they are good differences.

In the last few days, I was able to max out Spicy O’Clock to it’s overclocking limit of about 51.16 MHz on my LC 575 Mystic motherboard with OS-CON capacitors. It’s not entirely stable at that frequency because if I leave it on for a while and move the arrow pointer, I get what I describe as dust pixels following it. I can run all of the benchmarks completely except for MacBench. MacBench 3 works, but about 60% of the way through I get a Bus error. Once that happens, if I restart, I get a black screen. if I pull the motherboard and reduce the clock frequency, it starts working again.

initially, I thought it was temperature related because I tested in a room that was quite cool at between 15 to 18°C. But the following day I tested at 22°C and got the same results. Those are room temperatures, not component temperatures.

The reason these findings are significant is because prior to the VGA mod, using the stock 384x512 resolution, anything beyond about 49.3 MHz would result in a blue screen with artifacts that would vertically roll. That led me to believe it might be the speed limitations of the VRAM. However, after the VGA mod, I’m not seeing that rolling blue screen anymore, so I guess 60ns VRAM really can take you up to 50 MHz and a little more. However, the pixel dust after the arrow pointer at 51MHz indicates that 60ns VRAM is at its speed limit.

The question now becomes, why would the increased resolution of 640 x 480 allow higher clock speeds?

I’m still doing more testing today.

I asked Kay to do some more testing in light of my results, but I believe he’s busy so we must wait to hear what he has to say about that. But I think it’s clear to get the highest clock speeds you really need to have the VGA mod installed. Whether that is the regular VGA mod or the 13” high resolution mod too, is yet to be determined. Hopefully Kay’s testing will confirm that. And if you do the VGA mod, in accordance with my most recent video, you could confirm that too!

 

[Kay K.M.Mods]

@JDW I tried my best the last 2 days to catch you!
View attachment 2882
I removed the Kemet tantalum capacitors for lower ESR and stability BUT... I think I have a limitation regarding my LC33 that keeps me at 49mhz and no further!
View attachment 2883
Frequency readout displayed here at 24.420mhz. While it is MOST stable at 48mhz the machine can almost touch the 50mhz mark with some bus errors. Interestingly I also tried using an RC25 CPU in this logic board which was stable to 45mhz! which makes me hopeful that I may be able to find an RC40! (if any legitimate ones appear online).
View attachment 2884
The CPU itself also remains cool in this state using a stock cooler from quadra700.

You may rest easy up in the clouds of 50+mhz heaven my friend!

Great result. I've been doing this project with JDW, but there are only a few 040 machines on the 50MHz scale in the world. I think that there are software problems and ROM problems to stabilize this, so I think that it is difficult to solve it only by hardware.
I think JDW's mouse pointer problem has a limit of 60Ns, as he points out, but I can't solve it because delaying the clock timing should solve it.
I think more people will try this as well when his video is ready. And if there is a programmer in it, you may be able to hack the ROM with a disassembler.
This modification was popular about 25 years ago, but I feel that there should still be something that can only be done in 2022

 

[JDW]

I've been testing all day with Spicy O'Clock set to 49.43MHz (Clockometer value). Again, I have the VGA (640x480) Mod installed. Before the VGA Mod, the highest stable speed I could get was about 49.29MHz (serial ports not functional though). After many hours of testing at 49.43MHz using MacBench 3 and games like Doom, I found that System 7.1 is quite stable.

@Kay K.M.Mods found that when he tried to boot System 7.6 or OS 8.1 at very high clock speeds (higher than 45MHz?), the CC Mystic will freeze during boot. I confirmed that. Open Transport is the problem. I thought it was Quicktime too, but it isn't. I spent most of the time today fighting Control Panel & Extension conflicts though. No problem in System 7.1, but lots of Extension and CP conflicts in 7.6.1 and 8.1. Not as many problems in 7.5.5. Ultimately, I had to disable Conflict Catcher (shockingly!) to get System 7.6 to reliably boot. I can keep Conflict Catcher enabled in all other OS's though (7.1, 7.5.5, 8.1). Strange.

I grew tired of freezing to death in my cold bedroom (9°C), so I turned on the heater. I was working in System 7.6.1 at the time. After a while, I noticed a little pixel dust after moving the arrow pointer, but the machine continued to run. Pixel dust vanished when I rebooted into System 7.1.

I had the CC back case on, and the back panel on too, during all my testing today. (The back panel I am using today was 3D printed by Kay Koba and is quite nice. Not as nice as the LC575 panel he custom cut, but still nice and more easily mass produced.)

I restarted my CC many times today. Twice, I got the following Sad Mac error immediately after I restarted...



0000000F
0000000A

Not sure what that means, but when I restarted again, the Mac booted normally.

I did my testing today with a stick of 32MB RAM I had never used before in my CC Mystic. I pulled that RAM stick from a working Quadra 630 which had a 75MHz PM6200 motherboard in it. I doubt the RAM is an issue, but I did notice that the stock 32MB RAM SIMM that was originally in my Color Classic has capacitors on it, but the 32MB SIMM I pulled from the Q630/6200 doesn't have capacitors on it. Both seemed to be 60ns RAM as per the "6" in the part number. Photos below.

32MB RAM pulled from Q630 (PM6200):

​

​

​

32MB RAM that was in my Color Classic's stock 16MHz 030 Motherboard:

​

​

Note the capacitor CS6 (1pc on either end of the SIMM):​

​

 

[Drake]

I've been testing all day with Spicy O'Clock set to 49.43MHz (Clockometer value). Again, I have the VGA (640x480) Mod installed. Before the VGA Mod, the highest stable speed I could get was about 49.29MHz (serial ports not functional though). After many hours of testing at 49.43MHz using MacBench 3 and games like Doom, I found that System 7.1 is quite stable.

@Kay K.M.Mods found that when he tried to boot System 7.6 or OS 8.1 at very high clock speeds (higher than 45MHz?), the CC Mystic will freeze during boot. I confirmed that. Open Transport is the problem. I thought it was Quicktime too, but it isn't. I spent most of the time today fighting Control Panel & Extension conflicts though. No problem in System 7.1, but lots of Extension and CP conflicts in 7.6.1 and 8.1. Not as many problems in 7.5.5. Ultimately, I had to disable Conflict Catcher (shockingly!) to get System 7.6 to reliably boot. I can keep Conflict Catcher enabled in all other OS's though (7.1, 7.5.5, 8.1). Strange.

I grew tired of freezing to death in my cold bedroom (9°C), so I turned on the heater. I was working in System 7.6.1 at the time. After a while, I noticed a little pixel dust after moving the arrow pointer, but the machine continued to run. Pixel dust vanished when I rebooted into System 7.1.

I had the CC back case on, and the back panel on too, during all my testing today. (The back panel I am using today was 3D printed by Kay Koba and is quite nice. Not as nice as the LC575 panel he custom cut, but still nice and more easily mass produced.)

I restarted my CC many times today. Twice, I got the following Sad Mac error immediately after I restarted...

View attachment 2890

0000000F
0000000A

Not sure what that means, but when I restarted again, the Mac booted normally.

I did my testing today with a stick of 32MB RAM I had never used before in my CC Mystic. I pulled that RAM stick from a working Quadra 630 which had a 75MHz PM6200 motherboard in it. I doubt the RAM is an issue, but I did notice that the stock 32MB RAM SIMM that was originally in my Color Classic has capacitors on it, but the 32MB SIMM I pulled from the Q630/6200 doesn't have capacitors on it. Both seemed to be 60ns RAM as per the "6" in the part number. Photos below.

32MB RAM pulled from Q630 (PM6200):

View attachment 2896​

View attachment 2894​

View attachment 2893​

32MB RAM that was in my Color Classic's stock 16MHz 030 Motherboard:

View attachment 2895​

View attachment 2892​

Note the capacitor CS6 (1pc on either end of the SIMM):​

View attachment 2891​

This morning I tested my logic board (with LC33) in two configurations of analog boards. Firstly a unit with the "light VGA mod" described here: (https://powercc.org/640x480/).

- Oddly the machine would not display further than 47mhz in this configuration, with the typical symptoms of no display or scrolling blue screen.

Secondly I tested with a stock analog board and 512x384 locked resistor modded logic board.

- I have better luck with this configuration as I can push a smidge over 49mhz if I am lucky BUT only consistently under 49mhz with the oscillator adjusted below 24.450mhz.

The ram I tested with these configurations were various manufacturers, all of which are 60ns.

 

[JDW]

Hi @Drake ,

The SIMM in the upper left in your photo shows a good amount of capacitance on it, but it also has a transistor too. Not sure if capacitance on the RAM SIMMs really matters or not for stability at super high clock speeds, but since OS-CON capacitors are the ticket to the highest clock speeds with the Mystic motherboard, I am strongly giving thought to that.

You said "LC33" in your previous post. I assume that means an LC 68040 CPU without FPU and rated for 33MHz, correct?

The light VGA mod you referred to on POWERCC is Method #3 in my video, and is what I am using for all my testing now.

It's interesting you mention getting the blue, vertically rolling screen problem with your VGA Modded Mystic. After doing that same VGA mod, I am no longer getting the blue rolling screen, not even at 51MHz (although I do get the pixel dust when moving the arrow pointer). But before doing the VGA Mod, at the 512x384 resolution, I would consistently get the blue vertically scrolling garbage screen when I set the clock speed above 49.29MHz (as reported by Clockometer).

Is your Analog Board recapped?

I am not able to overclock my LC 040 CPU (the stock CPU that came in the Mystic motherboard) much beyond 43MHz. But the UTsource 040 I purchased, which has a fake marking that says it is a 40MHz CPU is the one I have been reporting the highest clock speeds with, reaching the maximum 51MHz of Kay's overclocker, and which is currently stable at just over 49MHz.

Yesterday, I reported that Conflict Catcher was causing a freeze at cold boot in 7.6.1 but no in OS 8.1. Well, this morning when I restarted into OS 8.1, I got the freeze. I booted from a floppy, moved the CP and Extension of Conflict Catcher into their respective "Disabled" folders, then moved Apple's Extension Manager (CP & Extension) back into the active folders, restarted, and all was well. So Conflict Catcher appears to be a problem in OS 8.1 too when running at the highest clock speeds.

 

[Drake]

Hi @Drake ,

The SIMM in the upper left in your photo shows a good amount of capacitance on it, but it also has a transistor too. Not sure if capacitance on the RAM SIMMs really matters or not for stability at super high clock speeds, but since OS-CON capacitors are the ticket to the highest clock speeds with the Mystic motherboard, I am strongly giving thought to that.

You said "LC33" in your previous post. I assume that means an LC 68040 CPU without FPU and rated for 33MHz, correct?

The light VGA mod you referred to on POWERCC is Method #3 in my video, and is what I am using for all my testing now.

It's interesting you mention getting the blue, vertically rolling screen problem with your VGA Modded Mystic. After doing that same VGA mod, I am no longer getting the blue rolling screen, not even at 51MHz (although I do get the pixel dust when moving the arrow pointer). But before doing the VGA Mod, at the 512x384 resolution, I would consistently get the blue vertically scrolling garbage screen when I set the clock speed above 49.29MHz (as reported by Clockometer).

Is your Analog Board recapped?

I am not able to overclock my LC 040 CPU (the stock CPU that came in the Mystic motherboard) much beyond 43MHz. But the UTsource 040 I purchased, which has a fake marking that says it is a 40MHz CPU is the one I have been reporting the highest clock speeds with, reaching the maximum 51MHz of Kay's overclocker, and which is currently stable at just over 49MHz.

Yesterday, I reported that Conflict Catcher was causing a freeze at cold boot in 7.6.1 but no in OS 8.1. Well, this morning when I restarted into OS 8.1, I got the freeze. I booted from a floppy, moved the CP and Extension of Conflict Catcher into their respective "Disabled" folders, then moved Apple's Extension Manager (CP & Extension) back into the active folders, restarted, and all was well. So Conflict Catcher appears to be a problem in OS 8.1 too when running at the highest clock speeds.

I 100% agree that OS-CON are the ticket!
In all my examples I am using the stock LC 68040 (33mhz) and 3 different logic boards as well. I would like to point out the least successful results were with a 1993/1994 revision B which has a different oscillator (Saronix). The other two silkscreened 1993 Revision A.
Possibly the circuitry for this revision B is different? as the oscillator is through hole. This board would ONLY go to 42mhz in both Vga modded color classic and stock, all recapped.

I know @Kay K.M.Mods adjustable oscillator is working around the original oscillator but I think there is something else at play for this revision B.

My results so far using Os-Con capacitors, 60ns Vram and different 60ns Ram sticks,
Revision A: 47 mhz (Vga mod) - 49 mhz (Resistor mod)
Revision B: 40 mhz (VGA, Resistor mod)

 

[JDW]

@Drake I must say it is very interesting that you could overclock the LC 040 CPU to 47MHz. I am unable to get my LC CPU much beyond 43MHz. Here's a photo of my LC CPU...

But with a full FPU edition 040, I can overclock to the maximum 51.16MHz. That is with the same 60ns VRAM and 60ns RAM SIMM, and OS-CON caps on the board.

Interestingly, the RAM that is soldered onto the motherboard is rated at 70ns, as per the part numbers on those chips. Since I have confirmed that slow 80ns VRAM prevents overclocking much beyond 42MHz, it is interesting the onboard 70ns RAM doesn't seem to be presenting much of an overclocking problem.

Anyway the Spicy O'Clock board connection points are made at the section of the motherboard shown below...

Drake's Rev.B LC575 motherboard:

JDW's Rev.A LC575 motherboard:

 

[JDW]

@Drake What OS's have you been testing with a high overclock? (Anything higher than 44.4MHz) I can get System 7.1 to work fine at any stable clock speed. System 7.5.5 wasn't too hard to get working at high clock speeds, and once working it consistently works. But System 7.6.1 and OS 8.1 have been giving me hell. OS 8.1 is worse than 7.6.1 in terms of freezing at cold boot, regardless of my having slimmed down all CP's and Extensions to the standard Apple ones, and despite the fact I tried a clean install of both OS's. After I get OS 8.1 to start booting, for example, it often won't boot the next time I restart. Again, that occurs only at high clock speeds and never occurs at 44.4MHz (approximate) or below. So again, if you could overclock beyond 45MHz and test OS 8.1 and/or 7.6.1, confirming if there are boot issues, that would add something important to this discussion, I think.

Kay has already told me that Open Transport needs to be disabled, and in his case, he recommends disabling QuickTime too. But again, even with all that disabled, I still have issues in those two OS's.

Thanks.

 

[MacKilRoy]

@Drake What OS's have you been testing with a high overclock? (Anything higher than 44.4MHz) I can get System 7.1 to work fine at any stable clock speed. System 7.5.5 wasn't too hard to get working at high clock speeds, and once working it consistently works. But System 7.6.1 and OS 8.1 have been giving me hell. OS 8.1 is worse than 7.6.1 in terms of freezing at cold boot, regardless of my having slimmed down all CP's and Extensions to the standard Apple ones, and despite the fact I tried a clean install of both OS's. After I get OS 8.1 to start booting, for example, it often won't boot the next time I restart. Again, that occurs only at high clock speeds and never occurs at 44.4MHz (approximate) or below. So again, if you could overclock beyond 45MHz and test OS 8.1 and/or 7.6.1, confirming if there are boot issues, that would add something important to this discussion, I think.

Kay has already told me that Open Transport needs to be disabled, and in his case, he recommends disabling QuickTime too. But again, even with all that disabled, I still have issues in those two OS's.

Thanks.

Do you have AppleTalk turned off in Chooser ?