Mac LC and DB15 to VGA adapter problem...

[dragon_x]

Windows 7 should work fine. I write Mac disk images from a Win7 PC with a USB floppy all the time. Are you using winimage? Maybe try a different image file? If you haven't already, check out https://winworldpc.com. They have a lot of Mac software packaged in PC-friendly formats. For instance, after grabbing and unzipping copy of OS 7.5.3 (https://winworldpc.com/product/mac-os-7/75), or whatever version you plan on installing, try using winimage to write the "Disk Tools 1.img" file to a floppy. That's a bootable image and will allow you to partition the HD prior to install.

BTW, I have my LCIII connected to a multi-sync LCD via a dip switch configurable DB15 - HD15 adapter. If you don't make any headway on the adapter build, I can meter the pinout of the configuration I was able to get working with mine.

I would ask You for the pinout of your adapter configuration. I have no success with that

I have a question. is the VRAM in the slot additional VRAM or is it the entire video memory?

 

[bibilit]

There is no vram onboard, the stick is required for early LCs. 

Still thinking something is not right on your Logic board. 

Have you replaced capacitors ?

 

[dragon_x]

There is no vram onboard, the stick is required for early LCs. 

Still thinking something is not right on your Logic board. 

Have you replaced capacitors ?

Not all cause I have no possibilities for that now. 
i am looking for adapter or working pinout for checking. 
i would like to replace capacitors as fast as I will find domenie who can help me with that. 
Mac booting, etc. The only issue is uncorrect picture. 

 

[dragon_x]

Mac BD15 to VGA adapter has arrived. Unfortunately Mac is not working properly in any mode. I bought capacitors to repleace them. I hope It will work after recap. 
Do You think that recap will help or maybe i have to search also other solution ?

 

[MrFahrenheit]

Mac BD15 to VGA adapter has arrived. Unfortunately Mac is not working properly in any mode. I bought capacitors to repleace them. I hope It will work after recap. 
Do You think that recap will help or maybe i have to search also other solution ?

View attachment 37591

That is definitely something that can be caused by bad capacitors. I strongly suggest a recap.

 

[dragon_x]

That is definitely something that can be caused by bad capacitors. I strongly suggest a recap.

hello, i have replaced the capacitors.  the picture improved and the computer can be used but unfortunately it is not good.  I had to rebuild two paths at the C9 capacitor.  I made them from thin wires and a capacitor is soldered to them.  connections checked several times.  What else can I do?  

the computer cannot see the scsi disk.  in addition, I thought it has a 6MB of ram but It has 4 MB.

greetings

 

[bibilit]

Probably a broken trace somewhere around the old capacitors. 

Hard drives are notorious for falling with age. 

 

[dragon_x]

Probably a broken trace somewhere around the old capacitors. 

Hard drives are notorious for falling with age. 

I have checked all connections before and after recap betwen cap pin and next possible place. the only one problem was path near C9 capacitor that i had to rebuild from thin wires. I wonder what else I can do.

Next thing is where to find working compatible hdd.

 

[MrFahrenheit]

I have checked all connections before and after recap betwen cap pin and next possible place. the only one problem was path near C9 capacitor that i had to rebuild from thin wires. I wonder what else I can do.

Next thing is where to find working compatible hdd.

The motherboard has 2MB soldered onto it.  Your SIMMs need to be installed in pairs.  So one of two things has happened here:  You have 2x 1MB SIMMs and you have the 2MB onboard= 4MB.  Or, your onboard RAM is bad, and you are only using the 2x 2MB SIMMs if that's what you had.

As for the bad video, is it at all possible your traces to the VRAM are bad, or the VRAM SIMM is bad ?

 

[dragon_x]

The motherboard has 2MB soldered onto it.  Your SIMMs need to be installed in pairs.  So one of two things has happened here:  You have 2x 1MB SIMMs and you have the 2MB onboard= 4MB.  Or, your onboard RAM is bad, and you are only using the 2x 2MB SIMMs if that's what you had.

As for the bad video, is it at all possible your traces to the VRAM are bad, or the VRAM SIMM is bad ?

thats good idea! I will try to check connections with VRAM, but picture on the screen is much better after recap. I hope to find solution.

 

[Byrd]

Check, replace VRAM if it's booting and working well sans the video glitches.

 

[dragon_x]

Check, replace VRAM if it's booting and working well sans the video glitches.

I dont have a vram repleacement unfortunately

 

[bibilit]

Was the board cleaned properly after recap ?

a bad trace can be hard to spot and is very time consuming. 

 

[dragon_x]

Was the board cleaned properly after recap ?

a bad trace can be hard to spot and is very time consuming. 

Yes. The board was cleaned before and after recap. I used isopropyl alcohol to clean It.

 

[bibilit]

Keep in mind that goo can be found everywhere if not cleaned properly, and cleaning only locally is not enough. 

Goo is conductive, and can short legs/traces. 

 

[dragon_x]

Keep in mind that goo can be found everywhere if not cleaned properly, and cleaning only locally is not enough. 

Goo is conductive, and can short legs/traces. 

I will clean board again

 

[dragon_x]

The board is in isopropyl bath...

 

[dragon_x]

Hello It is a beautiful day

My LC is working properly

Bath in isopropyl and toothbrush cleaning helped

The last thing is hdd. System don't see it. 
 

Thank you guys for you help.

Greetings

 

[bibilit]

What brand is your hard drive ? if not working open the lid and try spinning it by hand 

 

[dragon_x]

What brand is your hard drive ? if not working open the lid and try spinning it by hand 

It works mechanically, spinning etc, but system does not see It. Hdd is quantum. It was working in yamaha a3000 sampler before. I get hdd with Macintosh. Maybe i have to change hdd configuration but I dont know how cause there os no table configuration on It.