Takky power supply mod. Help please!

[Jaek_3]

Hello all, I recently acquired a Macintosh color classic and like a lot of people out there the 16 mhz CPU drove me up the wall. So I took it upon myself to Takky-mod it to try and wring out some better performance, and I was completely successful!

 

I slotted in a Macintosh Performa 630CD motherboard whose harness I used for the project and it worked like a champ. While 33 mhz is certainly better than 16, after a while it started feeling sluggish too. So I got my hands on a Power Macintosh 5500 motherboard and tried it out.

 

The Mac sound plays when I turn it on, but it's almost like the high-voltage is having trouble engaging on the CRT because I can hear it try firing up several times before finally turning on, sometimes that doesn't even happen and the monitor stays off. When the screen does finally glow to life, the picture has a lot of noise and the computer will lock up after no more than 30 seconds.

 

All this sounds to me like a power supply issue, something I read may require modification for this board. powercc.org, the site I followed to modify my CC, says my 5500 series board may require a 3.3V regulator and additional PSU mods I haven't performed. Now I'm not an electrical engineer, so I'll fully profess ignorance on the subject, but I'm a bit confused about how to proceed. I'm tripped up at the bit where the PSU in the diagram connects to the relay, and most everything after that point. 

 

Where do I connect the FG, N, and L lines going out from the new power supply and relay?

Where do I connect the N line from the new power supply into the relay, and where do I attach the second red wire going out from the relay?

 

Which leads are for what on the relay? Where do I attach the yellow and black wires going to 12V from fan terminals, and what value diode do I use? How do I tell which fan terminal on the analog board is for the yellow wire or the black one?

I would appreciate any help anyone can offer, and rest assured I won't be attempting this modification unless I know 100% what I'm doing. Everything works fine with a 5200 board also.

Edited October 12, 2019 by Jaek_3

[Jaek_3]

Actually thinking about it, is it possible that installing just the voltage regulator will stabilize the board’s performance? 

[Trash80toHP_Mini]

Dunno, but here's another diagram from the .jp CC hackers:

 

Maybe looking at it a different way might help?

[Jaek_3]

Well I soldered in the 3.3v voltage regulator and now the board is stable, but the visual noise remains. I don't think it's power related however as talking to this Takky CC owner with an even more powerful logic board than mine, it turns out his unit has neither a voltage regulator nor a new power supply... so is the problem a quirk of my particular logic board? Who knows.

 

Anyways I have a more serious issue now, 640x480 is too blurry. It's not bad, but it doesn't have nearly the sharpness the old 512x384 resolution had. Is there some way to make it so that I could switch between these resolutions? Setting the resolution down in Mac OS 9 makes the screen go crazy for a split second before shutting off.

Edited October 22, 2019 by Jaek_3

[Jaek_3]

YET another update to anyone who might benefit from this info in the future, replacing the caps on the logic board has almost entirely solved the visual noise I was complaining about earlier. It's still there but the screen doesn't look like an TV connected through RF anymore.

[Byrd]

Thanks for posting your progess - it appears all Takky upgrades are far from the same, with some quirks found along the way depending on varying approaches to the mod.  I've a G3 enabled Takky (not my modification) I'm pretty sure has no 3.3V regulator that surprisingly has never let me down.  I'm going to put a 2.5" MSATA IDE HD in there soon to reduce wattage draw.

[CC_333]

I believe the 3.3V line is used primarily for the 5500's PCI slots and not much else.

 

I could be mistaken, though, as I *really* don't know much of anything about Takky mods (I do have a Mystified CC (pun intended!), but that's pretty simple to do by comparison, involving only a logic board swap with a Performa 520 or 550, so not too relevant here).

 

c

Edited October 23, 2019 by CC_333

[Jaek_3]

Well in case anyone is interested, I guess I'll post some more updates on my Takky project

 

Currently, I'm trying to squeeze this Voodoo5 into the case and with some more snipping of the internal plastic it JUST barley fits. I haven't tested it out yet as the cheap little 3.3V regulator I installed had one of the leads just come clean off, so I've ordered a new one. Not that that'll probably matter much, as I highly doubt the power supply will be able to supply enough current for things to work.

 

Next order of business is to get an IDE2SD adapter to both lighten the load on the power supply and make room for the new power supply I'm sure I'm going to have to install.

 

I'd also like to design and 3D print a new replacement cover that also includes a slot for screwing down PCI cards!

 

Here's a picture of the size comparison between the Voodoo card and current logic board and the original 16mhz board of the original.

 

Edited October 25, 2019 by Jaek_3

[Byrd]

I like your style, Jaek_3; putting a Voodoo 5 in there is a great idea but I reckon you'd want to run that card off an external PSU just to be sure.  3DFX cards need to go in more vintage Macs

[mraroid]

Thank you for your posts.  I do enjoy them.  Please keep us updated.

 

I suspect you know about this already, but if not, here is the best on line source I know of for hacks of your CC.  Great detail

and a lot of good info:

 

https://powercc.org/

 

mraroid

[Jaek_3]

So after three days of internet scouring, I was finally able to locate the Mac Voodoo5 bios rom I needed to flash my Mac Voodoo5 from the PC firmware I installed on it a few years ago back to the original, and now it works just fine! Unfortunately I think the 225 mhz CPU bottlenecks the computer's performance but honestly I'm at the end of the rope as far as CC speed upgrades goes, that is, unless I want to sink $200 on an G3 L2 accelerator board.

I'll point out that this is running on the STOCK power supply and as of yet I've had no issues. I did order the parts to add a secondary power supply however, 

[Byrd]

Great work - keep an eye on heat output inside the casing for the V5.  I ended up shelving a Voodoo 1 in my TAM (which was magnificent BTW - so many good games for it which run smooth as silk); it simply got too hot in there.

[Jaek_3]

5 hours ago, Byrd said:

Great work - keep an eye on heat output inside the casing for the V5.  I ended up shelving a Voodoo 1 in my TAM (which was magnificent BTW - so many good games for it which run smooth as silk); it simply got too hot in there.

Yeah, I really just wanted to see it done haha. Currently I've got a kitchen fan parked right behind the CC blasting it at the max setting, that's worked out good so far.

 

What I've really been having trouble with is getting games to run, they really don't like the dual monitor setup but I can't seem to find a way to disable the internal CRT. 

[Byrd]

Hi Jaek,

 

With the Voodoo being a stand alone 2D and 3D card, the Mac OS/ATI drivers become confused as to which card is best to output video on when playing games, usually defaulting to internal video first.

 

I had the same issue here using a TAM (6500 innards essentially):

 

 

From what I've read elsewhere, disabling all the ATI extensions might help with 3D detection using another graphics card but it's not perfect.  As mentioned the small Voodoo 1 card I had worked great but hot, so I'm just using the stock video now and the external DB15 adapter.  I'd suggest trying a Voodoo 2 if you have and you won't have 3D detection issues.  I've read that Voodoo 3 PCI card doesn't like 5x00/6x00 machines especially those with G3 accelerators, so I'm, not going to bother with one of those (but I did learn the Voodoo 3 AGP can be flashed to Mac, that'd be great in a G4 tower!).

 

JB

Edited October 30, 2019 by Byrd