Color Classic Upgrade Questions

[macosten]

Hello! Not sure if I should post this in the LC subforum, since the CC is kinda both and this concerns a 550 board, but I regardless figure that this sub gets slightly more traffic so it's more likely to be seen here.

This is more of a troubleshooting question than a "what should I do" thread (but it's too late to change the title now, oops!); here's my problem.

Anyway, I just got and recently recapped my LC 550 motherboard to upgrade my CC with; up the RAM limit and VRAM limit, etc.

The problem is (or so I've deduced) that, whenever I try powering on the CC with the 550 board while I have my Sonnet Presto card in the PDS slot, the video/CRT doesn't turn on, even though the computer chimes.

To be clear:

• The 550 board works with no PDS card installed, with and without an FPU (the FPU didn't affect the bootup)
• The 550 board works with my spare Ethernet PDS card installed.
• The CC board works with the Presto.

I tried several times with and without the PRAM battery, and I tried sliding the board in shortly after powering on the computer (with and without the PRAM battery), all to no avail.

Anyone know what the problem might be? Are the Presto (not Plus) and 550/CCII just incompatible? I wouldn't think they are, since they're evidently supposed to work, but...?

 

[omidimo]

You will have to remove the VRAM from the motherboard for the Presto to work. 

 

[macosten]

You will have to remove the VRAM from the motherboard for the Presto to work. 

Tried the LC 550 board with the Presto with and without the VRAM already.

Out of curiosity, I tested what would happen if I left the VRAM in the stock board with the Presto installed - it corrupts the video, but it doesn't stop it from booting.

Thus, I'm pretty sure that's not my problem.

 

[omidimo]

Very strange, I know the original Presto had problems with the VRAM board. They did fix it with the Plus. 

Do you have any other PDS based mac to test the presto in?

 

[macosten]

Very strange, I know the original Presto had problems with the VRAM board. They did fix it with the Plus. 

Do you have any other PDS based mac to test the presto in?

It's not that the picture is garbled or blank when using the LC 550 board, it's that the CRT just doesn't turn on.

It turns on if I use the Presto in the stock board, and it turns on if I use the LC 550 board without the Presto/with a network PDS card.

...I don't happen to have another machine with an LC PDS, sadly. Maybe soon?

 

[omidimo]

Did you Zap the PRAM? 

Always helpful to have an LC around, they are dirt cheap. 

 

[macosten]

Did you Zap the PRAM? 

Always helpful to have an LC around, they are dirt cheap. 

I don't think it boots far enough to let me zap the PRAM - invoking interrupt, for example, doesn't yield the Chimes of Death, even after I hear the startup sound.

...I have taken the PRAM battery out several times, but zapping still isn't a bad idea - perhaps booting it up, then zapping, then shutting it down, then installing, and finally trying to boot up?

...yeah, LCs are cute, too. I'm going to look for one at some point; I think a 475 would be preferable since I could upgrade that 68LC040 to a full 68040... and I still have an LC Ethernet Card that needs a home

 

[omidimo]

Do you have the original CC board to try? Hopefully someone who had the original Presto can chime in. 

Q605/LC475 are pretty good, especially when maxed out.

 

[macosten]

Do you have the original CC board to try? Hopefully someone who had the original Presto can chime in. 

Q605/LC475 are pretty good, especially when maxed out.

I've already said that it works with the stock (original) board. It's just not working with the LC 550 board.

...yeah, they seem pretty nice, as the strongest pizza boxes.  :lc:

 

[EvilCapitalist]

I used an original Presto with a Color Classic on a stock board but I've only ever used a Presto Plus with my Color Classic II.  I've still got an original Presto I can try with the CCII and see what it does.

 

[macosten]

I used an original Presto with a Color Classic on a stock board but I've only ever used a Presto Plus with my Color Classic II.  I've still got an original Presto I can try with the CCII and see what it does.

If you could do that, that would be amazing.

...report back with the results, if you can.

 

[macosten]

...tried zapping the PRAM with the battery in, then installing the card. Still having the same problem. :-/

...do I just have a bad board or something, even though it works perfectly fine in every other way...?

I was able to get it to respond to restart keycombos and interrupt keycombos with the thing installed, now, though; I guess that's progress? But does this mean my AB is bad/needs recapping?

 

[macosten]

Spoiler

...perhaps I shouldn't post things as they happen, but now the 550 board doesn't seem to recognize the Presto at all (having it in the slot just has no effect), while the stock board still does.

...do I just have a bad board, or...?

Edit: Reseating it made it "regress". I'm wondering: could it be an Analog problem? Then again, if it was, I'd think I'd eventually hear the system beep as it tells me that the date and time are wrong...

Maybe it doesn't provide enough power to power the Presto, 550 LB, and the CRT? I'm skeptical that it's the issue, but, I mean, it's possible...

Alright, now, whenever I have the Presto in and the 32 MB of RAM out, the machine boots but doesn't recognize the Presto. When I have the Presto and the 32 MB of RAM in, it chimes and responds to the special key commands, but doesn't seem to boot.

...what gives?

 

[Johnnya101]

Can you check the power outputs? That would give you your answer. If it's anything below the 5 and 12 then that's your issue.

 

[macosten]

Can you check the power outputs? That would give you your answer. If it's anything below the 5 and 12 then that's your issue.

I... can't? How would I? I could get a multimeter (and learn how to use it, 'cause I don't know, but I'm sure it's simple enough), but even then, how would I test the lines? I assume the machine would have to be on while I'm doing that (and I assume that would be dangerous?)...

 

[macosten]

In case anyone's interested, I can say that the computer feels faster in different ways when using the LC550 board vs the Presto. It's hard to describe, honestly.

 

[EvilCapitalist]

If you're using the Presto on a stock CC board you're dealing with a 16MHz bus versus the 33MHz bus on the LC550/Color Classic II motherboard so even with the Presto the CC board will feel slower because of the bus bottleneck.  Between my Color Classic and Color Classic II, the II feels noticeably faster and they both have a Presto Plus.

Just finished trying my standard Presto in my Color Classic II and it didn't work for me either, with the exact same symptoms as yours.  If I left the extra VRAM in I'd get a boot chime and it would respond to a reboot command from the keyboard but nothing came up on screen and I could hear the HD wasn't doing anything.  If I took the extra VRAM out I wouldn't even get a boot chime but I could hear the CRT refreshing when I rebooted with the keyboard.

Granted, it's a sample size of 2 but it doesn't seem like the CCII/LC550 board and a regular Presto 040 work together.  Personally I'd use the 550 motherboard in your CC and save the Presto for an LC/LCII.

 

[macosten]

Granted, it's a sample size of 2 but it doesn't seem like the CCII/LC550 board and a regular Presto 040 work together.  Personally I'd use the 550 motherboard in your CC and save the Presto for an LC/LCII.

Huh. Perhaps it's a problem with the bus, then.

So in that case, if you're getting the same results I'm getting, I guess I'm not going crazy. Off to get a Presto Plus and an LCI/II, then?

 

[EvilCapitalist]

I probably should have checked this first but according to Sonnet (thanks to the Internet Archive) the only models compatible with the original Presto are the Color Classic, LC, and LCII (and the LC/LCII-based Performas).  That's pretty definitive in my book.  Strange that it specifically excludes the LC520 and LC550/CCII.

https://web-beta.archive.org/web/19970112065347/http://www2.sonnettech.com:80/product/presto/lc_50.html

LC and LCIIs are cheap and plentiful, the Presto Plus, not so much.  I haven't seen one come up for sale in quite a while.